MOVING TOWARDS A MORE LIVEABLE AND SUSTAINABLE CITY

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1 THE SB13-14 SERIES Organised and hosted by GBCe, the World Sustainable Building 2014 Conference, which closes the SB13-14 series cycle, will take place in Barcelona, Spain, in October Previously in the SB13-14 series, the year 2013 is hosting the Regional SB Conferences, taking place in 16 countries worldwide: Munich, Germany; Oulu, Finland; Vancouver, Canada; Colombo, Sri Lanka; Pomona, USA; Prague, Czech Republic; Coventry, United Kingdom; Seoul, Korea; Singapore, Hong Kong; Graz, Austria; Cape Town, South Africa; Guimarães, Portugal; Cairo, Egypt; Manila, Philippines; and Dubai, U.A.E. Also, in order to achieve greater coverage and global participation, GBCe has created a new category: World SB14 Barcelona SEED, events related to sustainable building and that can make contributions to WSB14BCN. A SEED already took place in Colombia in May 2013, and further contributions are expected. Under the theme: Sustainable Building Results: Are we moving as quickly as we should? World SB14 Barcelona aims to kickstart an action plan within the building sector which gives an effective answer - before to the challenges, both social and environmental, faced in all areas of the world: providing affordable housing for all, reducing the ecological footprint and promoting a new model of sustainable economic activity, focusing on decent employment. In order to do so, the Conference proposes three central areas of work: a global vision, to reflect upon the main topics of the Conference; transforming reality, holding debate between the main agents of the building sector; and creating new resources, where investigators and academics provide the knowledge and instruments necessary to define, monitor and reach the targets. Complementing these three main areas, several others encourage agents to take part in the Conference: evaluation tools; cities and policies; innovation and industry; workshops; Mediterranean area; and other regional areas. Content from all SB13s will feed these areas, making the World event truly global.

2 MOVING TOWARDS A MORE LIVEABLE AND SUSTAINABLE CITY Daniel PC Chan School of Architecture, Chinese University of Hong Kong, HKSAR, China In 1950, Hong Kong population was 2.2 million with 85% living in urban area. By 2030, it is predicted that the population will grow to 8.16 million 1 and continue to have 100% of the population living in urban area. Comparatively speaking, the world had 30% living in the urban area in 1950 and it is expected to increase to 60% 2 by 2030 with a total population of around 8.5 billion. We are experiencing the final shift of human population from agricultural life to cities, the effects of which are being felt around the world. As the world s finite material resources are depleting, they cannot be replaced once consumed. Consequently, our naturally concentrated resource becomes a human concentrated resource. It is predicted that world oil production starts to drop with environmental pollution problems become worsened. Biodiversity loss also becomes evident as a result of urbanisation. Food miles are great concern as it is a long distance that food travels between the locations at which it is produced and consumed. Climate change continues to remind us of its powerful existence with more extreme weathers, rising sea level and unforgiving hurricanes. While we are facing these challenges and attempting to re-align our existing infrastructure of cities to produce a more: Sustainable Liveable and Economically viable future, we need to ask many questions. Some of the questions include Are our cities ready to cope with climate change? What mix of housing type do we need in our cities? What geographic size and shape do we want our city to be like? Does this imply a change in development density? Who should make these decisions? And how? A number of sustainable city case studies are discussed: o Masdar City, United Arab Emirates 1 Hong Kong Census and Statistics Department The Guardian, Urban development Forum November 2011

3 o Sydney - Green Square - Barangaroo - Glenfield o Melbourne - Coburg - Russell Place Unitised Building o Oslo, Stockholm, Helsinki, Amsterdam, Zegrab and Adelaide (Integrated Transport Planning) These studies are focused on Carbon Reduction programmes and Sustainable Transport plans. To spearhead the sustainable refurbishment and retrofitting of existing building in Australia, a mandatory National Australia Built Environment Rating System (NABERS) has been implemented from 1 July 2010 whereby the government will provide a rating in the form of building energy efficiency certificate (from zero to six stars) which is valid for 12 months. Greening the built environment offer government the lowest cost abatement opportunities available. By 2030, Sydney and Melbourne target to retrofit 1200 existing commercial buildings. It plans to cut energy consumption (in CO 2) by 70% from 2006 level. Other demand side management strategies and measures include energy efficient street lighting, changing the electricity production raw material from brown coal to natural gas with further improvement to renewable energy such as solar, wind and biomass, employing smaller scale co-generation or tri-generation plant using natural gas, converting food waste to biogas in anaerobic digestion plant, implementing building integrated photovoltaic panel and solar thermal system coupled with smart metering and smart grid. However, there are few barriers to the carbon reduction initiatives for sustainable urbanisation. Lacking of a price for Carbon may be an issue as a financial driver. Regulatory barriers relating to grid connection and restriction on generating and selling energy need to be further discussed and resolved. Who will invest, own and maintain these local energy plants? What is the capability of these plants to adapt to an increased demand? Financial issues must be resolved as one of the top priorities. It also examines a number of world cities to review their transport system with a view of meeting our own sustainable transport objectives. Many Australian and European cities such as Sydney, Melbourne, Adelaide, Oslo, Stockholm, Helsinki, Amsterdam, Copenhagen all have adopted an Integrated Transport Planning approach promoting walking, cycling, tram, bus, light rail, underground rail and ferry system. The use of low and no emission vehicles, intelligent transport solutions, electric and solar electric bus, solar electric vehicle charging station are some of the examples employed.

4 To further improve the carbon reduction programme in Hong Kong we need to explore and consider new driver and incentive. It is proposed that a local Carbon Trading scheme should be explored as a pilot scheme, which may be extended in other areas and mainland if successfully implemented. A pre-requisite condition is to mandate the energy efficient certificate for all commercial building, similar to NABERS in Australia. The HKSAR government or its entrusted body will rate the actual energy performance of commercial building by conducting energy assessment and certificate. Any surplus energy /carbon dioxide saved compared with benchmark could be traded in a similar manner as Green Power which has been adopted and commercialised for some years under LEED and NABERS. The current Mandatory Building Energy Ordinance and Energy Benchmarking Study currently undertaking by Hong Kong Green Building Council have provided the fundamental understanding and detailed information to move towards this direction. It is interesting to note that 65% 3 of total electricity produced are consumed by commercial buildings. To achieve a positive result, the Government must be committed to lead and adopt a holistic approach for energy efficient retrofit of existing buildings and help business to reduce carbon emission. Targets and roadmap should be set up with the active participation of all stakeholders to draw policy, enact legislation, provide funding and incentive, engage finance sector, involve senior Government official to better co-ordinate different Bureau and Government department and reduce bureaucratic red tapes to smoothen the whole process. Natural gas tri-generation and co-generation plant in a smaller district is an effective way to reduce our city Carbon footprint. However, we need to overcome two hurdles which relate to our energy policy. Firstly, natural gas is not yet available to our commercial and residential end users. The conversion of natural gas to town gas increases our Carbon footprint by more than 10% during the manufacturing process. Town gas also carries a much lower calorific value as compared to natural gas. Secondly, there are government regulations which restrict the generation, distribution and sales of electrical power in Hong Kong. Before we respond to the first question asked earlier concerning our readiness for Climate Change, we may also need to think of a Climate Change adaptation strategy: 1. Loss prevention - take action to reduce the impact and vulnerability of Climate Change 2. Loss sharing - spread the risk to wider population. (insurance?) 3. Behaviour modification eliminate the activity and behaviour that cause the hazard of Climate Change 4. Relocation Move affected population or systems away from hazard induced by Climate Change 3 HKSAR Government EMSD report for 2010

5 In a metropolis city like Hong Kong, a sustainable transport planning is as important as Carbon reduction. In 2010, 30 % of our total energy consumption is categorised under Transport. With an increasing number of registered vehicles and traffic congestion, air pollution problem also becomes a major concern. Despite that good news from Hong Kong Observatory report in early 2013 that the overall air quality is improving and on a downward trend, the Air Pollution Indices for Mongkok, Causesway Bay and Central continue to record much higher level than our new Air Quality Objectives. To combat our increasing transportation energy and worrying air quality, we require leadership, vision and courage to adopt and Integrated Transport Plan and Zero Carbon Transport Future in 2030 as follows: Reducing car use by 50 % Initial focus can be made on Central Business District (CBD) and severely affected districts. Employing more electrical/renewable transport means/modes Solar electric bus, upgrade/improve tram and add light Rail system, hydrogen fuel cell vehicles Promoting walking by increasing pedestrian only zones particularly in congested area, creating more cycling routes, eliminating duplicated transport route and transportation inefficiency and road preferential treatment for low/no emission vehicles including public and private vehicles. It is to be hoped that we resolve two problems of our transportation Carbon footprint and air quality to meet World Health Organisation standards by adopting an innovative and Integrated Transport plan. Two innovative ideas/ systems may help the acceleration and advancement of sustainable transport city to meet the objectives: Hydrogen offers great advantage as a fuel for transportation (fuel cell vehicles) and buildings and storage of solar energy. It is suggested 4 that the best prospect is storing hydrogen in metal hydride. It is expected that buildings will not only using sunlight to split water (to provide hydrogen fuel) and absorbing carbon dioxide, but also storing hydrogen in the building as solar fuels. New Scientist reported in 2012 that Cyanobacteria (blue-green algae) and photosynthetic plants have good potential of converting and storage of solar energy into chemical bonds/energy. Cyanobacteria exist more than 3.5 billion years ago, live in water and can manufacture their own food through photosynthesis. To embrace the scientific challenge and materialise the whole process would lead us towards a more liveable and sustainable future. 4 Engineers Australia Journal May 2013

6 ACHIEVING ZERO CARBON FOR BUILDINGS IN A DENSELY POPULATED CITY AND A SUBTROPICAL CLIMATE Guiyi Li 1 Director of Zero Carbon Building Construction Industry Council 1 Corresponding Author guiyili@hkcic.org, Tel: (852) , Fax: (852)

7 ACHIEVING ZERO CARBON FOR BUILDINGS IN A DENSELY POPULATED CITY AND A SUBTROPICAL CLIMATE Abstract In Hong Kong, the buildings consume most of the energy and are the major contributor to the Green House Gas (GHG) emissions. GHG emission reduction requires rethink of the planning and design processes as well as behavioral changes. Construction Industry Council (CIC), as the construction industry coordination body in Hong Kong, has developed the ZCB, the first zero carbon building in Hong Kong. The main objective of the ZCB is to showcase the state-of-the-art eco-building design and technologies to the construction industry locally and internationally as well as to raise the awareness of low carbon living in Hong Kong. The ZCB integrates the state-of-the-art design and technologies within the context of a high density city and the sub-tropical climate. This paper presents the technologies, the energy strategy and the carbon strategies of the ZCB and highlights the importance of the behavioural changes as well as technologies in achieving the zero carbon emissions. Keywords: zero carbon building; zero energy building; passive design; active systems; renewal energy generation. 1. INTRODUCTION Buildings in HK account for 90% of electricity consumption and 60% of Green House Gas (GHG) emissions. Therefore, buildings are both a challenge and an opportunity for reducing GHG emissions, and the construction industry has a significant role to play in GHG emission reduction. To this end, Construction Industry Council (CIC), as the construction industry coordination body, has undertaken a number of initiatives including the development of the ZCB (in collaboration with the Hong Kong Government), the first Zero Carbon Building in Hong Kong. The ZCB aspires to showcase the latest eco-building design and technologies applicable to Hong Kong which is of a high population density in the subtropical climate, 2

8 and to serve as an education centre to inspire positive behavioural changes towards low carbon living. Completed in June 2012, it covers a total land area of 14,700 square metres surrounded by high rise office buildings. It is a 3-storey building with the following facilities and components: An indoor exhibition and education area to show case the latest zero/low carbon design and technologies An eco-home to promote low carbon living An eco-office for staff An eco-café to promote low carbon living A multi-purpose hall for conferences, seminars, exhibitions and corporate functions in a zero carbon environment A public green leisure space, which can also be used for outdoor exhibitions and events Hong Kong s first urban native woodland to promote biodiversity A ring path to demonstrate the concept and principles of "One-planet Living" Figure 1 Perspective View of ZCB 2. KEY DESIGN PRINCIPLES The main consideration in planning for the above components was to create a real use building blended with the environmental design and latest technologies. Being in the subtropical area, Hong Kong s summer is long (May to October), hot and 3

9 often humid. Afternoon temperatures frequently exceed 31 Degree C. The remaining months of the year are generally considered pleasant. As such building energy consumption peaks in summer due to air-conditioning. Keeping the buildings cool whilst minimising energy consumption in summer is the focus of the design consideration. In responding to the aspirations set for this project, the following 4 E principles were adopted: Experimental The ZCB shall be an experimental ground for the latest eco-building design technologies. Over 80 different environmental features and technologies are showcased in the ZCB. Most of the technologies are new. Some of them are used for the first time in Hong Kong such as the combined cooling, heating and power generation system running on the biofuel reprocessed from waste cooking oil. Whilst not all are essential to achieve the zero carbon emission target of the ZCB, they all serve the purpose of showcasing how the technologies work in practice. Evolving Technologies evolve fast. The ZCB is designed to have as much flexibility as possible for upgrade with the future technologies. Examples include the easy installation of the photovoltaic panels, easily upgradable eco-home and interactive displays in the mezzanine floor, and the adoption of a plenum floor system which houses all utility conduits and cables. Evaluation As not all technologies adopted have been proven in Hong Kong, evaluation of those design and technologies in terms of capital costs, operation costs, energy saving and carbon reduction would provide valuable information for promoting their wider application to the construction industry in Hong Kong. Accordingly, over 2800 sensors are installed throughout the building to record and monitor the key environmental performance parameters, such as CO 2, temperature, humidity, renewable energy generation, energy consumption, energy import from the city grid, surplus energy export and light level. That information is constantly fed into a Building Management System for recording, analysis, reporting and optimisation of building system performance. Education Even with the best design and all the latest technologies, it is still the people who use the buildings matter most in terms of energy saving and reducing carbon emissions. Much of the emphasis of the ZCB during the operation stage is education, particularly for the younger generation. Three sessions of guided tours are 4

10 provided each day to the public with interactive displays to explain the design strategies, rationale and benefit of the key design features and technologies adopted. 3. CARBON STRATEGY The ZCB has its mission in carbon neutrality. That is, the building has net zero consumption of energy generated from fossil fuel. The energy needed for its operation is provided by renewable sources on site. The building is connected to the city grid for exporting surplus renewable energy and when needed, for importing electricity from the city grid. Production of on-site renewable energy offsets the power consumed from the grid on an annual basis. The ZCB also goes beyond the common definition of a Zero Carbon Building by exporting surplus renewable energy to the local grid to offset the embodied carbon of its construction process and major construction materials. Figure 2 illustrates the carbon strategy based on the life cycle analysis of the ZCB. Figure 2 Illustration of Carbon Strategy 5

11 In order to minimize the embodied carbon, much effort went to the selection of the low carbon construction material and the low carbon construction method. Examples include the opting out for the reinforced concrete structure rather than the steel structure for the building, use of the timber and bamboo for the floor, fair faced external concrete wall and balanced cut and fill in the site formation. Table 1 summarises the comparison of the embodied carbon of the ZCB as compared to the scenario of the current standard practice. Table 1 Reduction of the Embodied Carbon as Compared to the Current Standard Practice Benchmark Embodied Embodied CO 2 of CO 2 ZCB (tonnes) (tonnes) Construction 150 Process 2200 Material Use 1400 Reduction 30% 4. ENERGY STRATEGY The design process of the ZCB adhered to an energy hierarchy as illustrated in Figure 3. The corresponding key passive design features and active systems of the ZCB are illustrated in Figure 4. The current best practice - Code of Practice for Energy Efficiency of Building Services Installation, also referred to as Building Energy Codes, was used as a starting point. Passive design opportunities for reducing the reliance on mechanical systems were then explored. The most noticeable passive design features in the ZCB are the maximal use of the natural ventilation and natural lighting and the optimal use of thermal insulation. The maximal use of the passive design measures leads to a reduction in energy needs by about 20%, compared to the benchmark of the Building Energy Code. The electrical and mechanical systems of the highest efficiency (also referred to as active systems) were selected. Main examples are the floor cooling system combined with radiant cooling from the ceiling, high volume low speed ventilation fans, separate cooling and humidity removal systems, active skylights and light tubes. The adoption of those active systems lead to another 25% energy saving compared to the 6

12 benchmark of the Building Energy Code. Sustainable Building 2013 Hong Kong Regional Conference Finally, the essential energy need is met through the on-site generation of electricity from the renewable sources. At the ZCB, 60% of the energy need is met by the electricity generated from the solar panels. A tri-generation system provides another 110% of the energy needs, using waste cooking oil. As such, about 100 MWh/year surplus electricity is expected to be exported to the city grid, which is used to offset the embodied carbon over a period of 50 years. Figure 3 Illustration of Energy Strategy Strategy Figure 4 Key Passive Design Features and Active Systems of ZCB Strategy 7

13 5. KEY PASSIVE DESIGN FEATURES Passive design refers to a design approach that uses natural elements to heat, cool, or light a building. The key passive design features of the ZCB are illustrated through the optimal use of natural ventilation, natural lighting, solar shading and thermal insulation, which are further described in the following. Optimization of Building Orientation and Form The orientation and shape of the building represents an optimised shape according to the local microclimate. (i) Natural Ventilation: The main southeast facing facade presents ample opportunities for capturing wind flow, in particular for summer wind for natural ventilation. The built form of the ZCB also works with the prevailing wind, creating larger negative pressure on the leeward facade and helping draw natural ventilation air through the building. (ii) Chimney / Stack Effect: The exhibition spaces and multi-functional room feature high ceilings. By integrating the ceiling height with the overall shape of the building, these spaces can be largely ventilated through stack effect. (iii) Shading: Angling the building with a sloping sectional profile reduces the south façade and increases the north facade. This reduces solar heat gain to the south. The southeast facade has deep overhang (about 45 degree) to shade the summer sun. (iv) Daylighting: The sloping sectional profile encourages natural lighting by introducing diffuse daylight through the clerestorey of the north facing façade. (v) Capturing Solar Irradiance: The gradually sloping roof (17 to 20 degrees) maximizes solar capture for the PV panels. Building Permeability To enhance cross ventilation, a permeable built form with large void deck at the reception hallway is employed to effectively ventilate the space. This will also benefit the local urban climate in terms of air ventilation. The ZCB runs for 30% of the year in the natural ventilation mode, including solar assisted stack ventilation. Ceiling mounted fans are also provided to delay air conditioning usage by more than 2 0 C when mechanical cooling is needed in the summer season. Hybrid Ventilation Mode Hybrid ventilation system is adopted, making use of natural ventilation when the outdoor 8

14 climate is comfortable. Façade Thermal Performance Direct solar gain through windows is reduced by the use of external solar shading and high performance glass. Window to wall ratios (WWR) for respective facades are optimised for daylighting and view without excessive ingress of heat. Relatively higher glazing ratio for transparency is used for the north facing façade. Deep overhang of the southeast façade provides shading while allowing good views towards the landscape area. The high performance glazing with fritted pattern controls the opacity of the two facades to avoid heat gain. Envelope Air-Tightness This is particularly important for reducing energy demand in Hong Kong s climate because dehumidification of high humidity infiltration has a disproportionally large impact on the capacity of mechanical cooling plant and its energy use. Good air tightness also eliminates the risk of condensation. Thermal Storage / Inertia The operation of the exhibition and the multi-purpose hall means the building will experience fluctuating loads. Exposed concrete slabs and cladding act as thermal storage to regulate temperatures in these spaces, to absorb temporarily intensive loads (from tour groups) and purges the excess heat during the occupation time through natural ventilation. 6. KEY ACTIVE SYSTEMS Active systems refer to the electrical and mechanical systems of the building. The key active systems of the ZCB include cooling, dehumidification, ventilation, lighting, solar control and comprehensive monitoring systems. Cross-ventilation and High-Volume-Low-Speed Fans This building is designed to address specific environmental challenges in the climatic conditions of Hong Kong. It features an open-plan cross-ventilated layout and is equipped with High-Volume-Low-Speed (HVLS) ceiling mounted fans, which promotes a gentle and uniform air flow throughout the building that can effectively counter the effects of the often humid weather (effective for approximately 30 to 40% of the year). 9

15 Under Floor and Radiant Cooling Systems Sustainable Building 2013 Hong Kong Regional Conference Under the air-conditioning mode, the building uses an advanced concept: high temperature system consisting of under floor air-supply, radiant cooling system and desiccant dehumidification. To achieve the desired room conditions of 26 C, 55% relative humidity, conventional system tends to overcool the supply air (10 to 14 C) to achieve dehumidification. In the ZCB, the humid fresh-air is pre-treated through a desiccant dehumidification process; hence the air and coil temperature can be significantly higher, thus reducing the cooling load on the chillers. Energy Cascade The design also addresses the shortcoming of the conventional electricity supply which is inherently inefficient due to the high-rate of waste heat rejection: normally only 40% of the source energy is captured. In the ZCB, the thermal energy from the combustion of biofuel is captured in an energy cascade that first utilises the highest grade heat for electricity generation, then adsorption cooling, and then desiccant dehumidification. As a result, 70% of the fuel energy can be captured. Comprehensive Monitoring There are over 2,800 sensors throughout the building to monitor and report on every aspect of the building performance. The results are displayed interactively in real-time and are used to optimise the building performance. Microclimate Monitoring Four microclimate monitoring stations are placed on and around the building to enhance the understanding of how the building performs and interacts with its surroundings. This is particularly important in the high-density context of Hong Kong. Automatic Windows and User Control A number of high-level windows are centrally controlled by coordinating their operation with the air conditioning strategy. At the same time, there are a number of low-level windows that can be controlled by the user to tailor the amount of ventilation and wind speeds at the occupied level. Task-Lighting Rather than uniformly lighting the building to a high-level of brightness, most of the building is illuminated to approximately 200 lux (appropriate for people circulation), while task-lighting is provided in areas where fine work occurs (office desk, display etc). Active Skylights 10

16 The skylights are used to optimise the daylighting and solar control. The shading fins are controlled by a computer and sunlight sensors and their shading angles are constantly adjusted to cut out direct sunlight as the sun passes over the sky. 7. RENEWABLE ENERGY GENERATION Renewable energy is generated on-site from 1,015m 2 photovoltaic panels and a 100kWe tri-generation system using biofuel reprocessed from the waste cooking oil. The renewable energy generation at the ZCB is more than its operation needs. The tri-generation (Combined Cooling, Heating and Power) system and the PV system generate approximately 230MWh/year. The ZCB itself is designed to consume less than 130 MWh/year of electricity. Surplus energy is exported to the city grid to offset embodied energy of its construction process and major structural materials. Tri-Generation System The tri-generation system is a combined cooling, heating and power generation system using biofuel. The waste heat from the power generation is harvested for cooling and dehumidification. The large-scale use of biofuel extracted from waste cooking oil is for the first time in Hong Kong. In a conventional power generation system, the combustion of fossil fuel releases carbon dioxide into the atmosphere that will otherwise have remained in the ground undisturbed. Biofuel is a form of renewable energy. Typically, waste cooking oil in Hong Kong is sent to landfill where further decomposition will lead to the generation of methane gas. Hence the emission factor for the use of biofuel from waste cooking oil is very low since it not only displaces the combustion of fossil fuel, but also avoids the generation of methane gas at landfills. PV Panels Over 80% of the roof is covered with crystalline PV panels. BIPV (building integrated PV) panels and thin film PV panels of new ultra-light-weight cylindrical CIGS (copper indium gallium diselenide) technology are also showcased. The PV panels produce 87 MWh of electricity per year, providing about 70% of the energy needs of the ZCB 8. LANDSCAPE AREA The greenery area covers over 50% of the total ZCB site and is planted with a total of 280 trees. The greening ratio is over 33%, equivalent to 215 trees per hectare. Each mature tree is estimated to be able to absorb around 23kg of carbon dioxide a year. The 11

17 greenery serves as carbon sink (although not counted in the ZCB carbon budget) and a heat sink to cool the local air. The landscape design improves the cooling effect and is estimated to be able to lower the air temperature by up to 1 C, leading to a positive impact on the local microclimate. A key feature of the landscape area is the planted urban native woodland, which contains some 220 trees of over 40 different native species. The variety of native trees and native shrubs provide food and shelter to attract native wildlife into the city, creating a high quality ecosystem embedded in a built-up area of the city. The planting pattern is random to emulate the natural woodland, with small trees interspersed amongst the medium and large trees aiming at the formation of a dense tree canopy in due course. Some trees with ornamental traits have been selected to improve visual amenity. It offers pleasant natural aroma and fresh oxygen and helps remove gaseous and particulate air pollutants to improve air quality. 9. CHALLENGES AND LESSONS With many new technologies adopted and that some are adopted for the first time in Hong Kong, ensuring all technologies perform collectively has taken an extensive testing and commissioning process. The ZCB is designed to operate on the natural cooling mode for about one third of a year. In its first year operation from June 2012 to June 2013, the ZCB was actually operated on the natural cooling mode for 40% of the time. Under the natural cooling mode however, the indoor air quality (IAQ) can only be as good as the ambient air quality. The cost of electricity generation from biofuel is about HK$3.5/KWh as compared to the current electricity cost of about HK$1/KWh from the city grid. To promote the wider use of the renewable energy, the environmental cost of the electricity generated from fossil fuel should be taken into account and perhaps reflected in the electricity tariff; or the renewable energy generation should be supported through public finance. The ZCB attracted a total of 22,000 visitors in its first year operation. They were made of 50% school students, 25% professional institutions and 25% general public. Those figures are encouraging and show that the public is interested in new ideas to reduce 12

18 carbon emissions. Sustainable Building 2013 Hong Kong Regional Conference The most interest showed to the Eco-home within the ZCB indicates that the environmental education tends be most effective when it is close to one s daily life. Achieving the zero carbon emission objectives means that the building performs to the design standards and that the occupier exercises strict discipline in energy use whilst without comprising the comfort level. The latter will have to be matched by behavioural changes and even mindset adaptation, which, based on the first year operation, can be more challenging than getting all the hardware installed and performing. 10. SUMMARY A variety of green design features and technologies are featured in the ZCB although not all are essential to achieving the zero carbon emission objectives. The purpose is to showcase how those green design features and technologies work in practice and how they can contribute to energy saving and therefore carbon emission reduction. To achieve the zero carbon emission over the whole life cycle of the building, the key considerations were: selection of the low carbon construction material and lean or low carbon; construction method to minimise the embodied carbon; optimal use of the passive design measures; selection of the most energy efficient electrical and mechanical systems; and selection of the most appropriate renewable energy sources. Whilst it is not expected to have many zero carbon buildings in Hong Kong in the foreseeable future due to the technology and land constraints, most of the technologies showcased in the ZCB are applicable to the high density cities in the subtropical climate such as Hong Kong, for energy saving and carbon reductions. The importance of behavioural changes, culture shift and education towards low carbon living cannot be emphasised more. 13

19 BUILDING PERFORMANCE: FABRIC, IMPACT AND IMPLICATIONS Christopher A Gorse, David, Glew, Dominic Miles-Shenton, Dave Farmer and Martin Fletcher Centre for the Built Environment, Leeds Sustainability Institute, Building Physics and Performance, Leeds Metropolitan University, Leeds LS18AJ 1

20 BUILDING PERFORMANCE: FABRIC, IMPACT AND IMPLICATIONS ABSTRACT While some buildings and retrofit projects are achieving significant steps forward, demonstrating their ability to provide thermally resistant and resilient structures, others fail to achieve their target allowing the unwanted flow of heat energy into and out of the building. Maintaining a comfortable internal environment within buildings of poor thermal performance creates an unnecessary impact on the natural environment, adds unwanted emissions and exacerbates the problem of fuel poverty. Whole building heat loss tests were used to measure the thermal performance of buildings under heated conditions, during the tests the movement of energy around and through the building elements was observed. The 39 tests reveal significant differences in expected performance compared with that actually tested in the field. Heat flowing though some buildings exceeded that designed by over 50%. An overview of the test methods and elements that contribute to this deviation in whole building performance is presented and the impact that this is having on the UK energy demand is calculated. The potential consequences in carbon and energy required as a result of the difference have also been calculated. The results suggest that with respect to new builds the deviation between fabric expected and actual performance could emit an additional 0.06 mtco 2eq per annum, based on the conservative estimate of 120,000 dwellings produced equivalent to approximately 14 million in energy bills. Unless addressed this could will affect every new year s worth of additional stock thus after 25 years the cumulative wasted emissions resulting from the building fabric performance gap could be around 30mtCO 2eq. Keywords: Building Forensics; Thermal Performance; Zero Carbon Buildings. 1. INTRODUCTION: THEORETICAL ENERGY EFFICIENCY The value of energy, whether supplied by fossil fuel or through renewable sources increases as the demand per person and the population grows. Intrinsically linked to the value of energy is its cost, not only in terms of finance but resources consumed and emissions generated. Unfortunately, underperforming buildings not only impact on the demand of the energy commodities, increasing their value and supply cost, but carry a direct financial consequence to the building operator and add an unwanted carbon 2

21 emissions burden. Buildings should perform as expected and not require additional energy to achieve normal operation (Stafford et al. 2012a; 2012b). Currently, so few of the existing 22 million homes (CLG, 2011a) in the UK operate close to the standards expected and legislated for that the whole building stock is in need of an upgrade. Meeting the nearly zero standard is a challenge. The retrofit market for domestic buildings is estimated at 200 billion over the next 20 years (King, McCombie & Arnold 2012). With an average 10,000 for each building upgrade a spend rate of 7 billion per year is required up to 2019 and 15 billion from 2020 to 2030 (King, et al. 2012). If this money is not to be wasted, the industry must build reliably and with confidence. Unfortunately, the industry has been woefully weak on building quality, especially achieving thermal performance standards. 1.1 REGULATORY REQUIREMENTS IN CONSTRUCTION: ENERGY EFFICIENCY NOT TESTED Due to the lack of reliable processes for rolling out buildings that operate within tolerance, the consistency and reliability of energy efficient buildings and thermal upgrades is proving problematic. The industry produces 120,000 new properties a year (CLG, 2011b; UK Statistics Authority, 2011), not knowing if the standards claimed are being achieved. Currently the mechanisms used to test actual energy consumption do not adequately address thermal performance. UK Regulations, and much of that across the world, do not require tests of actual building thermal performance. The Standard Assessment Procedure (SAP) that is used in the UK checks the design for compliance with the Building Regulations, specifically addressing the legislative requirement for conservation of fuel and power. However, neither the Regulation nor SAP requires that the whole building actually performs as expected. The Reduced Data SAP (RdSAP) assessments, used for thermal upgrades, also contribute to the machinery that helps determine a building s environmental impact, although it is based on a scoring and rating systems working from design and basic inspection data. The information from SAP or RdSAP is used, as part of the data, to rate the building s performance from A G, within an Energy Performance Certificate (EPC). At the moment EPC s are comparative tools, offering a simple expected energy performance; they offer a mechanism to compare one building s expected energy efficiency to another, but do not show the buildings actual efficiency. Although, not applicable to domestic buildings, the Display Energy Certificates (required for public buildings greater than 1000m 2 ) do show actual energy usage, and while this improves the transparency, it does not provide information on the building fabric or services performance. DECs provide space heating energy demand as a result of the combined impact of the building fabric, services and occupants. The effectiveness of the fabric and efficiency of the services are fundamental. If building fabrics and services underperform, additional energy will be consumed to achieve the relative comfort of a functioning building. Where there are significant defects in the building and service operation it may not be possible to achieve reasonable comfort conditions. 3

22 While it may not be appropriate to test the building performance of all buildings, it is essential that further information is gathered through sampling the buildings, prototypes and retrofit innovations. Feedback on improvements and interventions is essential. Understanding characteristic behaviour under different conditions is fundamental to improving building performance. 1.2 COMPARISONS WITH OTHER INDUSTRIES: TESTING OF ENERGY EFFICIENCY Regulated home appliances such as refrigerators are thoroughly tested, only having their relative energy rating awarded once the kwh/year efficiency is known. The European Commission Directive (EUE-lEX 2012) and resulting UK Energy Conservation regulation (HMSO 2004) dictates that: 6 (1) No supplier shall place on the community market a regulated appliance unless he has established technical documentation sufficient to enable the accuracy of the information contained in a label or information sheet The technical documents referred to shall include, amongst other criteria, relevant measurement tests performed, under harmonised standards, calculations and details of mathematical models for calculating performance. In time, the construction industry may not be able to avoid adopting similar standards. The Kyoto Protocol is influencing all European Directives. Even where the current EPDB is not quite so prescriptive, regulation will eventually evolve and the legislation of each country will ensure that all products, including buildings, perform to that specified, contracted or to the performance criteria which has been insured under warrantee. With few exceptions, the construction industry does not know how buildings really measure up to the standards and what needs to be done to ensure that buildings are not substandard. While the industry does not routinely measure the thermal performance of buildings, as the cost of energy rises users increasingly demand information on energy efficiency. The introduction of smart meters brings the possibility to explore energy use during occupied and unoccupied periods. Through further work to disaggregate the energy signatures of the fabric, services and occupants eventually performance information can be fed back to the user without the need for scientific testing. The disaggregation of in-use data to explore building fabric performance has been undertaken with limited degrees of success (Sutton et al 2011), further exploration of the methods below and their relationship with energy signatures uncovered will, in time, provide detailed information on performance. Currently, few research projects are collecting the breadth of data that has the potential to provide the insight required. The methods described below provide an insight to the data that can be collected and over time it is expected that the knowledge gained will help to inform construction professional and, via smart metering and other intelligent systems, the information will be fed in an understandable format directly to the user or facility manager. 4

23 There is much to learn with regard to the effective and efficient performance of buildings. The collection and disaggregation of data based on building, services and occupant behaviour should eventually enable feedback allowing occupants the ability to see if they are using the building efficiently and if the building and services are operating as required. 2.1 MEASUREMENT METHOD: MEASURING ACTUAL BUILDING PERFORMANCE The actual performance of a building can be assessed through scientific field tests such as those used in Technology Strategy Board Building Performance Evaluation Programmes (TSB 2013) and those conducted by the CeBE group at Leeds Sustainability Institute (LSi, 2013; Gorse et al. 2012). Discussion surrounding building forensics and whole building testing can be found through Annex 58 of the International Energy Institute and on the Leeds Sustainability Institute web pages (Fletcher et al 2012; Lsi 2013; Sutton et al. 2012). Measurements of the overall building performance are useful to determine the amount of actual energy required to heat and cool a building. Also forensic investigations are important to determine reasons for underperformance if a deviation is found. To understand why a building underperforms information is required on each element, component and junctions that form the whole building. The forensic investigation methods can also provide significant information and identify the actual cause of the discrepancy. The coheating test determines the actual heat loss through the building envelope. This is achieved by heating the internal environment to an elevated temperature and maintaining the temperature. As the external temperature changes, the power input into the dwelling responds to maintain a stable temperature. As the outside temperature drops more energy is required to heat the dwelling and as the outside temperature rises less energy is required. By monitoring the power input against temperature differential between internal and external environments, the heat transfer through the building can be calculated. Losses due to ventilation, heat gains from solar and variations due to the wind are also considered within the calculations (Johnston et al. 2013). Thirty nine coheating tests were used to measure the thermal performance of new buildings and existing buildings, before and after interventions were made. A summary of the heat loss coefficient is presented in Figure 1. The graph shows that the buildings predicted heat loss is lower than that achieved. There are a few exceptions to this, occurring where the initial understanding of the fabric construction was inaccurate. Due to an underestimate of the fabrics thermal performance, the predicted heat loss in this case exceeded that measured. It is important that the design information fed into assessments is correct, where design information is missing full building surveys and forensic investigations are important to determine the construction of the building s. 5

24 Figure 1 Whole Building Heat Loss, 39 coheating tests (forensic investigation undertaken on all buildings) 2.1 FORENSIC INVESTIGATION Forensic investigations were used as a diagnostic tool to identify the cause and effects of building failures or underperformance. The investigation of buildings is critical when trying to understand why certain results have been obtained. Whereas other tests provide context and identify anomalous results, it is the forensic investigation that identifies the actual defects that are responsible for any deviations found. A range of different forensic investigative techniques have been undertaken in these studies. 2.2 CONSTRUCTION ANALYSIS When testing new build properties regular visits are made during the construction process to make observations as the building is being built, renovated or retrofitted. The timeline images of the construction process can be particularly revealing when attempting to determine causes of poor performance. Still photographic and video images are recorded at key stages. By regularly visiting properties to be tested during the construction phase, factors such as design change, material modification and poor workmanship can be identified, and help with determining any later performance problems. If unexpected heat flow is recorded or found through thermocouple, heat flux readings or observed using thermography, a review of drawings and photographic material may expose the reason for the heat flow or air movement. 2.3 HEAT FLOW THROUGH BUILDING ELEMENTS Interpreting the energy performance of a building element based on the stated U- values of building elements is often unreliable because the stated U-values come from measurements made under standard laboratory conditions. In reality, the U-value within an element may vary considerably. In situ measurement can be made using heat flux sensors in combination with temperature sensors. Heat flux sensors were used to 6

25 measure the rate at which heat passes through a material or building element. This data, together with data for the difference between internal and external temperature, can then be used to calculate an apparent In Situ U-value. By calculating in situ U- values it is possible to not only ascertain the actual performance of building elements, but to identify areas which are performing particularly poorly. Figure 1: Equipment for wall forensics: Differential pressure sensors, heat flux plates, surface and internal thermocouples, air flow transducer 2.4 AIRTIGHTNESS TESTING As air leakage or infiltration is a major factor in building heat loss, air tightness is an important consideration. Unlike ventilation, which is the intentional and controlled flow of air through a property to maintain the safety and comfort of the occupants, air leakage is uncontrolled air flow through gaps/cracks, leading to draughts, heat loss and heat gain. Leaks are often obscured from vision by internal finishes or external cladding, and so correct methods must be used for adequate assessment. The leakage may be observed using handheld smoke puffers or filling the building with smoke and pressurising, or through thermography under dwelling depressurisation, and may be quantified using anemometers and differential manometers. 2.5 THERMAL IMAGING Thermal imaging is useful for assessing the In Situ thermal performance of buildings, and provides an effective visual representation of heat losses. Thermal imaging identifies the warmer and cooler regions of a surface, and so assists in the understanding of thermal losses from a building. For example, thermal imaging may highlight colder areas of an external wall when viewing from the inside, which would suggest the presence of a thermal bypass, missing insulation or perhaps variations in moisture content. From this indication, further tests such as applying heat flux sensors, air flow sensors or hygrometers to the region can then further investigate possible regions for a cooler area. It is in this sense, therefore, that thermal imaging operates with the same scope as that of standard photographic data, as a tool to aid decisions about subsequent tests. 7

26 Figure 2: Thermography showing cold air movement and cold spots under depressurized conditions. 2.6 BUILDING PERFORMANCE MODELLING In the context of full building testing, modelling offers potential to inform and optimise physical test procedures. By understanding the interactions on a theoretical scale, features of testing such as sensor location and equipment positioning can be optimised to ensure the highest level of accuracy. In the evaluation of the building and elements, computer modelling software is used to determine projected performance of construction details and whole buildings, with calculations based on the performance of individual materials, usage and exposure. This is particularly useful when assessing the thermal performance of a property and individual elements in different locations, under different conditions and different climates or to model the impact of defects, alterations and improvements. 2.7 IN-USE MONITORING AND BUILDING USER SURVEYS In-use monitoring is a final stage of full scale testing, obtaining data on completed buildings under realistic occupation. Such testing can be particularly revealing with regards to occupant behaviour, and also gives information on the energy use of internal appliances. Furthermore, in-use testing allows the performance of technologies such as mechanical ventilation heat recovery (MVHR) devices and photovoltaic panels to be assessed. A wide range of data can be obtained from occupied buildings, based on the needs of the research. This can be as broad as looking at total energy use, or as specific as isolating particular appliances within the home to assess their individual contribution. In-use data can then be used to inform interested parties on building performance and the effect of occupants on this. In-use monitoring studies have also been combined with building fabric performance assessing the ability to separate the effects of building fabric under occupied conditions (Sutton et al. 2011). 2.8 SAMPLE OF RESULTS FROM THE BUILDING FORENSICS All reports that have been made public and fully describe the observations made during the building forensics process can be found in the documents on the LSi (2013) web page, a further summary and discussion can be found in Gorse et al. (2012) 8

27 The problems identified in Table 1 are a result or combination of poor coordination, management, sequencing, workmanship, design and buildability. Product substitutions, poor information management and inadequate attention to the detailing of component interfaces also contributed to some of the problems. The following list represents an insight into some of the problems found that led to significant thermal bridging, bypass and airtightness problems as well as component failure. The list is not exhaustive. Table 1: Thermal Performance: Management, Inspection and Supervision Issues Some common problems observed Displaced or incorrectly fitted insulation allows thermal bypass. Where rigid partial fill insulation was used it was pushed off the surface of the wall creating voids around the insulation, allowing free flowing air. With changes in weather and other phenomena that affect air pressure, the movement of air and heat energy bypasses and circumvents the insulation. Discontinuity of insulation. Obstructions meant that there were gaps in the insulation. The irregularity of surface to which the insulations was placed prevented a close fit. Construction interfaces, that required cuts to the insulation to ensure a complete covering were overlooked or poorly fitted. Gaps found in cavity socks thus failing to provide an effective continuous seal. Insulation not placed properly, not butted up together and not built up to the correct thickness. Air, moisture and vapour barriers installed and then punctured to provide service entries, preventing the barrier to function properly. Uncontrolled air movement leads to thermal transfer, bypass and moisture movement within the fabric. Insulation was sometimes removed to fit services and not properly reinstated. Complicated and difficult to build designs created difficulties and poor quality product. Modifications made to the design can result in changes to the size of components. Fitting components with different sizes to that specified meant they were either too small, resulting in gaps, or too large, needing to be cut. Air barriers and vapour control layers were sometimes fixed in the wrong positions making them ineffective. The correct interface between the air and thermal barrier is important. In some cases instructions were not provided on how to seal barriers around fittings, penetrations and junctions. Folding and layering of building fabrics, such as vapour barriers, is problematic. Multiple layering to make up joints around corners and junctions needs some thought to make an effective seal without excessive build up. Incorrect use of tapes and sealants was common, specialist tapes are needed for different surfaces. Prefabricated components, such as windows and loft hatches sometimes did not effectively seal. Services were positioned too close to the wall making it difficult to seal behind them. 9

28 Hidden services were rarely air-sealed. Mortar beds were not filled and the gaps in the fabric were sometimes not sealed. Sealing coats only applied to open easy to access faces. Gap sealants were applied at surface level rather than properly fed into the gap. Incorrect lifting and moving of prefabricated structurally insulated panels caused damage. Incorrect expansion strips were sometimes used, making an ineffective seal. Junctions were not sealed. Points of air-leakage and infiltration were found around thresholds, windows and doors, between frame and breather membranes, around and through roof lights, roof panels, at the ridge, eaves and between roof panels. Air leakage was found around light roses, electrical sockets and other service fittings. Air leakage occurred through flooring panels that were damaged and poorly sealed. 2.8 INTERVENTIONS AND EFFECTS Throughout all of the studies there have been efforts to feedback knowledge to designers, contractors and manufacturers. Improvements have been made and new interventions tested. The Temple Avenue project (CeBE 2010) is a typical example of staged intervention demonstrating the improvements that can be made. A 1930 s property improved to the same standard as two energy efficient prototypes. Another example from the study is the party wall intervention shown below. Prior to the insertion of full cavity insulation, the partially filled cavity was allowing free flow of air and considerable thermal bypass, following the intervention the fabric exhibits control over the thermal movement and significantly reduces the effective heat flow. The results show significant improvements to the thermal performance of the wall. Prior to the intervention of full fill insulation the wall failed to provide an effective barrier to the outside elements. The variability of the heat flow before the insulation fill was introduced suggests that the wall is not effectively sealed, is experiences problems due to air infiltration, possible bypasses and general breaches of the building fabric. Building envelopes that do not offer constant thermal resistance will experience uncontrollable heat transfer through the fabric during cold and hot days. Variable wind pressure and direction also have a dynamic and adverse effect on such fabrics. The graph (figure 3) shows how insulation added to existing walls can create a consistent and performing fabric offering the desired resistance and creating a separation between internal and external environment condition. 10

29 Figure 3: A partially filled cavity exhibiting characteristic signs of thermal bypass and air movement, the full fill intervention creates a fabric that controls movement and significantly reduces heat flow. (Courtesy Leeds Metropolitan University and Knauf Insulation Building Physics Research) The building forensic and heat loss studies have been met with questions regarding the relative cost of the performance gaps and the benefits in financial terms if interventions are made. Equally, the question has been raised as to the likelihood of financial incentive schemes introduced by the UK government and the potential of them being effective if gaps in performance are common. The remainder of the paper attempts to address some of the related issues associated with the UK government s Green Deal (DECC 2012a; 2012b). 3.0 FINANCIAL AND POLICY INCENTIVES FOR CHANGE AND IMPLICATIONS Historic energy bills and data derived from their National Energy Efficiency Dataframework (NEED) has been used by the Department for Energy and Climate Change (DECC) to assess the amount of carbon actually saved by eco-renovation schemes compared to emissions that were predicted by the calculation engine SAP. They concluded the measures underperformed in reducing domestic space heating by around 50% of their technical potential (DECC 2012b) referred to as a performance gap. This analysis informed predictions for new policy launched in 2012, the Green Deal. 11

30 The performance gap therefore manifests as underachievement of policy. The Green Deal implemented in 2012 is intended to provide a large scale upgrade of the existing inefficient housing stock and assumes this default performance gap of around 50% for each retrofit. Reducing this would have great implications in terms of carbon and cost. In the UK the Green Deal was implemented to provide loans to householders so that they can install at no or low upfront cost eco-improvement measures like insulation and condensing boilers which may be repaid heating bill reductions. The performance gap jeopardises this policy mechanism. Aligning actual energy reductions with predicted savings therefore is paramount to the Green Deal s perceived success and the ability of householders to payback loans without incurring excessing interest repayments. 3.1 FINANCIAL AND POLICY RESEARCH METHOD Using a scaled down or corrected energy saving estimates in policy to mimic the performance gap is achieved using an in-use factor. This phenomenon was first observed by the Homes Energy Efficiency Database (HEED) which showed previous similar schemes such as the Energy Efficiency Commitment (EEC) and Carbon Emissions Reduction Target (CERT), both designed to encouraging greater uptake of home insulation and more efficient boilers were not as effective as initially predicted. A performance gap of around 50% on average was observed using energy bills before and after measures were observed the impact of this on the Green Deal is shown in Table 1. Table 1: Green Deal GHG savings in 2022 (Derived from DECC 2012b) Insulation type Savings / household SAP (kwh) Corrected savings (kwh) Performance Gap % Number of households National GHG saving (mtco 2eq) Solid Wall1 7,945 4,373 55% 955, Cavity Wall 4,569 2,272 50% 2,517, Loft % 1,640, The reasons for this performance gap are not explored in detail in their report but are supposed to be due to insulation s underperformance (perhaps due to improper installation or fabric failure), SAP s assumptions being unrealistic compared to actual buildings, and some walls being inaccessible for installation to be fitted. The concept of comfort taking is also mentioned as a cause whereby householders will enjoy warmer homes (as a result of insulation) rather than make reductions to their energy use. The rank importance of these factors contributing to the performance gap remains unknown. Acknowledgement of the performance gap in the Green Deal predictions raises the question why a similar in use factor approach is not applied when using SAP for other energy prediction purposes such as in Building Regulations compliance. This research attempts to identify how much of the gap is attributed to building fabric. It draws on the 39 coheating tests shown in Section 2.1 of this paper and these heat loss data form the basis of annual energy consumption estimates calculated using 1 Average of three SWI types 12

31 degree days data for York 2 (assuming a base temperature of 15.5 o C) according to the CIBSE TM41 (2006) guide where:. (Eq: 01) Heat Demand (kwh) = Degree days x Heat loss (W/K) x 1000(W) x 24(h) The 2013 Carbon Trust default conversion value of kgco 2eq / kwh of gas is used to derive the resulting carbon emissions assuming a system efficiency of 80% and ignoring other incidental gains and losses. Then benefits of using these data are that the assessments were undertaken on unoccupied properties that were intensively studied and whose thermal properties were being deliberately upgrade, thus the influence form occupants enjoying comfort taking and any errors due to inaccessibility can be disregarded when interpreting the results. Similarly ventilation assumptions in SAP used to predict heat loss have been replaced by actual measurements in this data thus further reducing errors via model assumption accuracy. Thus this assessment is an accurate reflection of the influence on the performance gap caused by the quality of building fabrics and their installation. This form of micro research supports the macro approach taken by DECC, which can only identifying the scale of the gap not its cause. 3.1 FINANCIAL AND POLICY RESEARCH RESULTS AND DISCUSSION Table 2 shows a relationship for heat loss data if considered in carbon, dwellings are anonymous for purposes of data protection. It is notable that the predicted emissions were almost always lower than the measured. The range of the fabric-only derived heat loss performance gap identified was between -9% and 58% across the sample. This implies that insulation material and installation quality can have a significant but variable impact on the performance gap. Where the measured performance was in fact greater than the predicted a negative value is recorded. 2 Gillygate, York, ENGLAND, UNITED KINGDOM (1.08W,53.97N) based on 15.5oC and 22months (August 2011 to May 2013) 13

32 Table 2: Performance gap of eco-refurbishments and eco-new builds (taken from CeBE) Household Heat loss measured and predicted (W/K) Predicted space heating demand (kwh/annum) Measured 3 heat demand (kwh/annum) Additional Emissions/m 2 (kgco2eq) 4 Performance gap ,421 6, % ,398 9, % ,889 11, % ,889 10, % ,512 11, % ,512 10, % ,333 6, % ,333 5, % ,410 6, % ,410 6, % ,018 12, % ,272 15, % ,680 13, % ,396 14, % ,656 12, % ,051 9, % ,217 8, % ,100 10, % ,370 10, % ,167 9, % ,533 8, % ,383 22, % ,143 15, % ,595 9, % ,590 10, % ,177 12, % ,210 11, % ,404 18, % ,849 12, % ,849 9, % ,672 7, % ,872 13, % ,878 7, % ,944 6, % ,449 13, % ,090 10, % ,090 9, % ,395 2, % ,019 2, % Average 26% 3 based upon a calculation involving measured data and assumptions regarding heating patterns 4 Assumes system efficiency of 80% and excludes incidental gains or losses 14

33 The average performance gap is 26% which validates to an extent the scale of DECC s assumption that around 50% of the predicted emissions will not be achieved, though additional research into the remaining 24% is needed and further studies may inform how useful an average gap is considering variations in housing stock, age, type and condition are great. The performance gap shown here may be lower than DECC s estimate for two reasons; 1) Firstly it excludes the other factors influencing the performance gap an 2) the properties presented here are all aspirational low-carbon homes and were aware the study was taking place. This means their eco-measures may have been more carefully installed than normal and it may be argued the performance gap would have been higher if these properties were randomly selected. The fact that the performance gap was still sizable despite giving advanced notice to installers shows that the fabric-only performance gap may not be due simply to complacency or use of lower specification materials but that there may be fundamental structural or technical impediments to the accurate installation of insulation and that current best practice may not be fit for purpose. Assuming the consumption figures in Table 1 are accurate the gap caused directly by insulation quality and installation may therefore be equivalent to savings of 1 mtco 2eq / annum in 2022, for the 5 million homes estimated to take part in the Green Deal by its final, around 222 million (assuming on 0.04/kWh in 2013). In addition if roughly 120,000 new homes are built annually in the UK with an estimated annual gas use according to Ofgem (2011) of 16,500kWh (of which space heating makes up only two thirds) then extrapolating the observed performance gap of 26% discovered here due specifically to insulation materials and their installation means that perhaps an additional 0.06mtCO 2eq ( 14 million or 115 per house) is unnecessarily being emitted (spent) by new houses every year. Unchecked this will occur for every new year s worth of additional stock thus after 25 years the cumulative wasted emissions could be around 19.5mtCO 2eq. This data set is small, the extrapolations are large and do not pay heed to difference in building construction types or changes in climate among many other factors. The results are not normally distributed and there is a high degree of sample variation since the other influences mentioned and building specific characteristics can vary enormously. It is recommended more data be collected on the performance of insulation materials and their installation before these numbers can be considered authoritative but the highlight the issues well. Accurate building simulation assumption, understanding occupant behaviour including comfort taking as well as on surmounting the physical obstacles that can limit the installation of eco-measures in homes also need further investigation before the performance gap can be fully tackled. 4.0 CONCLUSION The paper has provided a brief introduction into the UK Building Regulations relating to energy and conservation. To meet the zero carbon standards it is clear that considerable change to the thermal performance is required and that the current method of validation which considers only the designed building performance is ineffective because of the performance gap. The case is made that post construction 15

34 building forensics could placate this. It is anticipated that the regulatory framework will change to require improved performance. The testing methods show that it is possible to achieve low carbon buildings. Where deviation in thermal performance occurs it is possible, through forensic measures, to identify the contributing factors, undertake remedial measures and feedback information to improve the design and building performance. Currently fiscal measures are being used to promote change (the Green Deal), the question is raised whether the measures adequately account for the performance gap. The research has shown that the application of an in-use factor by DECC of around 50% to revise down the Green Deal s carbon emissions savings predictions is a valid approach. Such an acknowledgement is not made in other regulatory spheres such as building regulations for retrofits and new builds, undermining policy goals for carbon reductions. This research highlights that the major factor in the performance gap is likely to be due specifically to the quality of insulation materials and their installation, causing a gap on average of 26%. However it also highlights the heterogeneous nature of buildings and the fabric performance gap may be as high as 58% or as low as -9%. Greater acceptance and appreciation of the performance gap in the wider built environment could improve aspects of policy, Building Regulations and research and wider benefits surrounding reducing fuel poverty. The variability within the sample and sparseness of data presented here highlights the need for more research in this area to further refine the definition of the factors that contribute to the performance gap and identify their rank importance so that work can begin on minimising the performance gap and reducing carbon emission from buildings. A significant concern is that if the sizeable nature of the performance gap continues, the cumulative impact in emissions is considerable. 6.0 REFERENCES CeBE (2010) Report to Joseph Rowntree Housing Trust, Temple Avenue Project Reports; Leeds Metropolitan University, < 2013] CIBSE (2006) TM41 Degree Days: Theory and Application < ion&revision_id=76> [accessed 2013] CLG (2011a) Housing: Live tables on dwelling stock (including vacants), Table 100: 2011, Communities and Local Government. < tisticsby/stockincludingvacants/livetables/> [accessed 2012] CLG (2011b) Net Supply of Housing < [accessed 2012] DECC( 2012a), National Energy Efficiency Data-Framework, Summary of analysis using the National Energy Efficiency Data-Framework 16

35 < [accessed 2012] DECC (2012b) Final Stage Impact Assessment for the Green Deal and Energy Company Obligation, < [accessed 2013] Eur-Lex (2012) Access to European Law. Commission Directive 94/2/EC of 21 January 1994 Implementing Council Directive 92/75/EEC with regard to energy labelling of household electric refrigerators, freezers and their combinations. < ] Fletcher, M, Gorse, C, Stafford, A and Sutton, R (2012) Full Scale Dynamic Building Testing: Roadmap Document 1:1 Outline of Test Methods and Equipment. International Energy Agency, Annex 58, Reliable Building Energy Performance Characterisation Based on Full Scale Dynamic Measurements. Bilbao, Spain, April 2-4th Gorse, C, Stafford, A, Shenton, D M, Johnston, D, Sutton, R and Farmer, D (2012) Thermal performance of buildings and the management process. In: Smith, S.D (Ed.), Proceedings 28th Annual ARCOM Conference, 3-5 September 2012, Edinburgh, UK. Association of Researchers in Construction Management, HMSO (2004) Energy Conservation: The Energy Information (Household Refrigerators and Freezers) Regulations Her Majesty s Stationary Office <held in> Legislation.gov.uk: The National Archives < [accessed 2012] Johnston, D. Miles-Shenton, D, Farmer, D and Wingfield, J. (2013) Whole House Heat Loss Test Method (Coheating) Leeds Metropolitan University, < ccessed 2013] King, D, McCombie and Arnold S (2012) The case for centres of excellence in sustainable building design. London,The Royal Academy of Engineering LSi (2013) Leeds Sustainability Institute, CeBE Resources, < [accessed 2013] OFGEM (2011) Typical domestic energy consumption figures, Factsheet 96 < %20fig%20FS.pdf> [accessed 2013] Utley and Shorrock (2006) Domestic Energy Factfile, DECC < [accessed 2013] UK Statistics Authority (2011) Assessment of compliance with the Code of Practice for Official Statistics: Statistics on Housing in England (Department for Communities and Local Government, Report 117, 30th June 2011, < 2012] Stafford, A, Gorse, C. and Shao, L (2012a) The Retrofit Challenge: Delivering Low Carbon Buildings, Report no. 4. Energy Saving Trust & Low Carbon Futures,<[ March

36 Stafford, A, Bell, M. and Gorse, C.(2012b) Building Confidence: A Working Paper, Report no. 8. Energy Saving Trust & Low Carbon Futures, < March 2012 Sutton, R. Gorse, C. Miles Shenton, D, Bradley, J.Bell, M. Wingfield, J, Thomas, F. (2011)Energy Performance Feedback: An Exporation of data needs explanatory power, Report to Technology Strategy Board, Leeds Metropolitan University, < >[accessed 2013] Sutton, R, Stafford, A. Gorse, C. (2012) The Coheating Test: The value of a number. International Energy Agency, Annex 58, Reliable Building Energy Performance Characterisation Based on Full Scale Dynamic Measurements. Bilbao, Spain, April 2-4th TSB (2013) Building Performance Evaluation, Outputs < [accessed 2012] 18

37 High-density Sustainability and Liveability The Case of Hong Kong Prof. John NG 1 Director, Hong Kong Green Building Council 1 Corresponding Author john.ng@hkgbc.org.hk. 1

38 High-density Sustainability and Liveability The Case of Hong Kong Prof. John NG Director, Hong Kong Green Building Council ABSTRACT Hong Kong is renowned for its compact urban typology comprised of vibrant highdensity development connected by an efficient public transport system. For years, the model serves Hong Kong well, giving rise to a thriving economy with a relatively low energy use per household. Like many other cities, it faces the immense risks of climate change and the universal quest for sustainable development. Hong Kong must strive for a transition to low-carbon living. Meanwhile the urban living environment of Hong Kong is facing multiple challenges: worsening air quality due to cross-boundary air pollution, marine and road-side air pollution, municipal solid waste, energy wastage, nature conservation and yet a shortage of housing supply, offices and quality public spaces. The multiplicity of these issues demonstrated that the sustainability of development is intricately connected with high-density liveability. Examining reports on comparing sustainability and liveability across the world s major cities suggested that, while Hong Kong s strengths lie in its compactness, the low car ownership and bountiful natural environment, much remains to be done towards the other goals of social and environmental sustainability. In this regard, the building sector is of paramount importance for two major reasons: firstly, with the building sector consuming around 91% of the electricity of Hong Kong, the city simply cannot achieve low-carbon living without transforming this sector. Secondly, the built environment serves as topsoil for nurturing the much-needed liveable environment for the wellbeing of its people. A study of some of the highest-rating projects of BEAM Plus, the local green building labelling system, indicated that, while green building assessment encourages energy reduction and water saving practices, promotes excellent indoor environmental quality, as well as increases greenery coverage, there are a number of less explored areas. The roles and boundaries of green buildings must be readdressed to improve both sustainability and liveability in a high-density urban context. Keywords: BEAM Plus; Hong Kong; Liveability; Sustainability. Biography Prof. John NG is a professional Architect, Town Planner and Urban Designer. He has more than 30 years experience in the planning, design, construction and project management of highdensity housing and redevelopment projects. Awards of excellence were won by a number of these projects covering Architecture, Planning, Urban Design, Research and Green Building Design. John has presented extensively in international and local conferences on sustainable communities, microclimate, high-density housing and community development. He is a Director of the Hong Kong Green Building Council, the Chairman of its Green Labelling Committee, Chairperson of the BEAM Society Limited, Honorary Secretary and Director of the Professional Green Building Council, and a Council Member of the Hong Kong Institute of Urban Design. He is Honorary Professor of the Department of Urban Planning and Design, University of Hong Kong, and Adjunct Professor of the School of Architecture, the Chinese University of Hong Kong. He is advisor and member of a number of government committees and NGOs, and an active volunteer in environmental protection, community development, green building and post-quake reconstruction. 2

39 High-density Sustainability and Liveability The Case of Hong Kong Prof. John NG Director, Hong Kong Green Building Council Introduction Located at the south-eastern tip of the mainland of China, at the mouth of the Pearl River Delta, Hong Kong is a small city with a total land area of 1,104 square kilometres. For years, Hong Kong develops itself into a thriving international financial centre with impressive economic development, while the city s stunning skyline continues to woo visitors around the world. With seven million inhabitants dwelling in this small city, Hong Kong is also one of the most densely developed cities with an average population density of 6,540 persons per square kilometre (HKSARG a, 2013). Mong Kok, one of the busiest districts in Hong Kong, hits the Guinness Book of Records as the most densely populated place on the planet, with over 130,000 people per square kilometre 2. Adding to this immensity is the surging number of visitors to Hong Kong, which was almost 42 million in 2011 (Hong Kong Trade Development Council, 2012), and it is still on an increasing trend. How does Hong Kong attain sustainability and liveability commensurable to be Asia s world city in such high-density and compact urban environment? This paper will focus mainly on the built environment and new buildings in particular. Firstly there will be a review in various international surveys on sustainability and liveability fronts, followed by an outline on the strengths and challenges faced by Hong Kong in its high-density development. In the second part, there will be an analysis of 57 building projects assessed by BEAM Plus, the local green building assessment tool between mid-2010 and mid The discussion will try to shed light on the role of buildings in driving high-density sustainability and improving liveability in Hong Kong. Finally, it will identify the less explored areas and indeed the roles and boundaries of green buildings which must be re-addressed to achieve both sustainability and liveability. Positioning Hong Kong Comparing to other international cities, Hong Kong is considered economically vibrant and it continues to excel with its efficiency, vibrancy and diversity. On the sustainability front, the high energy consumption and higher levels of carbon emissions that come with it are the main concerns. Given the vast concentration of population and resources, the high energy consumption seems inevitable. Effective use of resources and energy is therefore particularly vital. Studies showed that high density development seemed to be a positive factor in reducing energy consumption (Norman et al, 2006). Earlier study by Newman and Kenworthy (1989) indicated that, population density had a negative relationship with fuel consumption per capita. As Figure 1 shows, comparing 2 Source as adopted from blog post on 3

40 to other major cities in the world, Hong Kong had extremely high population density with low average fuel consumption. Fig 1. The relationship between energy consumption per capita and population density among major international cities 3 While energy consumption and sustainability tops the urban agenda, the liveability of a city is getting increasing attention. The Centre of Liveable Cities and Urban Land Institute (2013) in Singapore examined the principles of achieving high liveability, particularly in high density setting. Figure 2 showed the distribution of world cities in terms of density and liveability, of which the latter is measured by Mercer s Quality of Living Survey (Centre for Liveable Cities and Urban Land Institute, 2013). Both Singapore and London achieved high liveability in a high density setting, while Hong Kong was falling behind in liveability. Likewise, in the world liveability survey conducted by the Economist Intelligence Unit (EIU) on international major cities in 2012, it measured parameters covering five categories, namely stability, healthcare, culture and environment, education and infrastructure. Hong Kong did not perform outstandingly in the survey (Economist Intelligence Unit a, 2012). In a subsequent survey by EIU in 2012, Hong Kong was ranked the first as the Best Cities, based upon a new index, the spatially adjusted liveability index (Economist Intelligence Unit b, 2012). The new index is formed with an added category of spatial characteristics to the existing liveability index of EIU. As Hong Kong scored particularly well in spatial characteristics, which concern sprawl and natural assets, it got a substantial jump in the ranking to top the list, despite scoring in pollution and cultural assets were relatively low. The adjusted index sheds light on two important components of liveability - the provision of effective public transport and the access to the natural environment. According to the latest population statistics, the birth rate of Hong Kong remains low, with the total fertility rate of 1,253 per 1,000 women, which is among one of the lowest of the world (HKSARG a, 2013). At the same time, with the longevity of the local 3 Figure adopted from the original graph is from Newman & Kenworthy, 1989). 4

41 population, of which male and female life expectancy is 80 and 87 respectively (HKSARG a, 2013), the population of Hong Kong is rapidly aging. The proportion of elderly people aged 65 comprised around 13% of the population in 2012, and it is expected to comprise 30% of population in Hong Kong by 2041 (HKSARG b, 2013). Considering liveability for elderly citizens furthers the meaning of liveability. The report by Stanford Center on Longevity (2013) states that the concept of liveable communities calls attention to the ways the physical, social, and economic infrastructure of cities and towns can promote or hinder older residents ability to age in place. While liveability in general applies to the quality of living of overall population, in practice, the population policy has to be taken into account including the steady growth of 150 daily individuals from the Mainland 4. This is particularly relevant in view of tight housing supply and limited land resources, other services, amenities, etc. The liveability of Hong Kong has to take into account the changing demographic change and trend. This will not be discussed in this paper. Fig. 2: The Liveability Matrix Diagram (Centre of Liveable Cities and Urban Land Institute, 2013) Wonders never cease Almost twenty years ago, when visitors came to Hong Kong by plane, they would end up in one of the most amazing airport in the world, which was located exactly in the heart of a dense urban population. This explained why many visitors had an impression that Hong Kong was a dense concrete jungle. The high-rise compact urban development has an efficiently-run public transport system. The metro system in Hong Kong carries over 4 million passengers a day (MTRC, 2012), and the three major bus operators carry over 3 million passengers a day (HKSARG c, 2012). The extensive network of public transport ensures smooth flow of people from different locations with little reliance on private cars. According to the data of World Bank (2013), the number of passenger cars per population of 1,000 is 59 in Hong Kong, which is substantially lower than the world average of From a sustainability point of view, the collective transport system reduces significantly the carbon footprint at an individual 4 For additional information, please refer to 5

42 level due to the low reliance on private mobility solutions. The well-developed transport system and infrastructure position the city favourably in a world calling for more collective mobility solutions. With the operation of the new international airport at Chek Lap Kok, visitors now can have a peek of the beautiful countryside of Hong Kong upon their landing. Despite the dense urban inner city, about 75% of the territory is not developed and 40% of the land mass in Hong Kong is designated as country parks. Attributed to the enactment of Country Parks Ordinance in 1976, 24 country parks and 22 special areas, including marine reserves and the wetland park, were established for natural preservation, covering a wide land area of 44,239 hectares (HKSARG d,, 2013). Above all, most of these country parks and natural reserves are easily accessible by public transport. They make the perfect hideaway for the city dwellers, and form a solid basis for longterm sustainability on ecology and biodiversity. Pressing challenges Although Hong Kong has achieved remarkably in the areas of public transport and natural preservation, the city is also facing pressing environmental and social challenges. Firstly, on the issue of air pollution, the health of the local population is put on a heavy toll with the deteriorating air quality in Hong Kong, most of which has to do with roadside pollution from outdated models of work vehicles as well as the often overlooked marine pollution. According to Clean Air Network (Hong Kong), a local NGO on fighting for clean air in Hong Kong, the mid-year Air Quality review on air quality showed that the local air pollution levels during the period of January to June 2012 exceeded the WHO s annual air quality guidelines, with only two exceptions (CAN, 2012). Great improvement has been found in 2013, with sulphur dioxide concentrations reduced by 25% on average comparing to 2011 levels, while roadside air pollution remains poor (SCMP a, 2013). Swift action is much needed. The Environment Bureau along with Transport and Housing Bureau, Food and Health Bureau, and Development Bureau issued in early 2013 a Clean Air Plan for Hong Kong. It is intended to develop a comprehensive plan entailing solutions on roadside air quality, marine emissions, power generation and non-road mobile machinery. Diesel commercial vehicles (DCV) are the main sources of roadside pollution. A new DCV replacement programme aims at replacing the pre-euro 4 DCV to Euro 5 model, along with other initiatives like urban greening, pilot green transport fund and regional fuel switch at berth for tackling marine emissions (HKSARG e, 2013). Secondly, another inconvenient truth is waste management. At present, there are 13,458 tonnes of wastes disposed to landfills every day, of which majority is municipal solid waste (Environmental Protection Department, 2012). With limited land resources and the associated negative environmental impacts, landfilling is not an effective longterm solution for waste management. Subsequently, Hong Kong Blueprint for Sustainable Use of Resources was produced by Environment Bureau in May 2013 (Environment Bureau, 2013). It gives an overview on key actions the government would spearhead, including driving behavioural change through policies and legislative measures, mobilizing communities for waste recycling and reduction, as well as investing in needed infrastructures like organic waste treatment facilities. Specific targets include setting the target of reducing 40% of municipal solid waste (MSW) on a per capita basis by 2022, to transform the waste management structure by 2022 through recycling, incineration and landfilling; and to invest in organic waste 6

43 treatment facilities, waste-to-energy MSW treatment and landfill extensions. These proposals had been criticized heavily by some green groups and local citizens (SCMP b, 2013). Tackling the waste problem needs concerted efforts from the government, business community and the public, in particular, soliciting support from the public remains critical. The issue of the Blueprint report is a decisive first step in addressing the issue. Thirdly, the building sector accounts for about 90% of the electricity consumption and more than 60% of GHG emissions (HKGBC, 2012). The city simply cannot achieve low-carbon living without transforming this sector. The built environment also serves as topsoil for nurturing the much-needed liveable environment for the wellbeing of its people. Therefore green building remains on the top of the agenda and takes a pivotal role to reduce energy consumption and respond to climate change. Apart from developing Kowloon East into a low-carbon community, an inter-departmental steering committee, under the lead of the Secretary for the Environment, was formed to promote green building. The committee will strengthen the co-ordination among government departments to formulate implementation strategies and action plans, while maintaining close dialogue and co-operation with relevant sectors and stakeholders (HKSARG f, 2013). This paper will focus on green building and its immediate built environment. Fourthly, the preservation and conservation of nature, and the related ecological issues stay high in the public agenda and attract significant debates in most Environmental Impact Assessments relating to major developments, such as North East New Territories New Development Areas 5, Lok Ma Chau Loop 6, etc. With the extensive land mass dedicated as natural reserves, Hong Kong is blessed with rich biodiversity of flora and fauna, and all kinds of animals. Almost 3,000 kinds of flowering plants, more than 2,000 moths, 110 dragonflies and 230 butterfly species turn Hong Kong to their home (HKSARG g, 2013). More than one third of total bird species in China can be found in Hong Kong. The Mai Po Marshes was established as a restricted area for it is a major stopover point of Asia s migration routes for birds (HKSARG h, 2013). The wide range of species finding Hong Kong as their homes indicates that, the city is striking a delicate balance between its urban and economic development and that of natural preservation. Hong Kong, in response to China as one of the 193 contracting parties of the UN Convention on Biological Diversity since 2011, is now in the course of developing its Biodiversity Strategy and Action Plan before 2015 (AFCD, 2013). Another critical challenge facing Hong Kong is the under-supply of housing, in particular affordable housing. With the limited land supply in Hong Kong, for years, the Hong Kong housing market has been criticised for its speculative activities. In recent years, the housing issue is again under the spotlight as there is a rising number of people living in substandard homes, including those notorious caged homes and subdivided flats, which often lack basic amenities and are in poor hygiene and safety conditions. The Hong Kong Long Term Housing Strategy Steering Committee was formed in September 2012 to review and devise long-term housing strategy in Hong Kong (HKSARG i, 2012). The Consultation Document was released in early September It will be a supply-led approach with government taking a proactive role in the provision of public and subsidised housing. The overall housing supply target proposed is 470,000 in the next 10 years (HKSARG j, 2013), while the figure will be examined annually; priorities for housing would be given to elderly and people living in inadequate housing, including sub-divided units (HKSARG k, 2013). The issue of housing is particularly pertinent to the liveability of Hong Kong, if well planned and 5 For information, please refer to 6 For information, please refer to 7

44 designed, the challenge may be a great opportunity to uplift overall liveability, attractiveness and sustainability of the built environment. Adding to the under-supply of housing is the demand for office spaces. As the traditional central business district areas are approaching their full capacity, the shortage of office space is increasingly prominent. This can potentially hamper the vibrant business activities. The Financial Secretary announced a steady and adequate supply of Grade A Office in early 2011 (HKSARG l, 2013). Government is consolidating the existing CBD in Central and developing new office nodes outside the CBD, such as Kowloon East, Quarry Bay, Wong Chuk Hang, etc. The revitalization plan for the Kowloon East district posed a rare opportunity to address the issue. With the old industrial buildings no longer in use, many buildings are turned into commercial or hotel use through wholesale conversion and major retrofitting. The Government established a specialised office, Energizing Kowloon East Office, to oversee various visionary initiatives in the district to turn it into a second CBD as well as a low carbon and sustainable community. The estimated total supply of 5.4 million square metres of office space alone will double the existing stock in Central. It is expected that with the revitalization of the district, not only there will be an increase in the much needed office space, but also a vibrant and sustainable community with high quality public spaces (Development Bureau, 2013). The massive building supply and the transformation of the public realm pose challenges to our wisdom in urban development as well as some rare opportunities in creating low carbon urban living and making Hong Kong s second CBD more sustainable and liveable. How do we address these multiple challenges? It is instrumental to adopt a holistic and integrated approach. The high density of population and buildings, intensity of activities, shortage of land supply, public objections will add on the complexity of the challenges. These challenges are all impacting on the liveability and sustainability of Hong Kong to varying degrees. A closer look into these issues indicated that many of these issues interact with one another. For instance seeking new land may be in contrast to the goals of nature preservation; building more homes and offices may shoot up electricity use; supporting local recycling often requires large plots of land, etc. A holistic approach in examining the liveability and sustainability is needed to embrace the complexity of the issues. Liveability and sustainability Liveability attains to the Quality of life is often tied to the opportunities available to people to the meaning and purposes they attached to their lives and to the extent to which they enjoy the possibilities available to them. (UN-Habitat, 2013). While Nobel Lauareate Amartya Sen attributed Quality of life is essential for any city to prosper (UN-Habitat, 2013). According to the Hague Centre for Strategic Studies, urban liveability consists in the development of attributes and resources that help make the city pleasant to live in, and attractive for people, visitors and business (Chivot, 2011). The Hague Centre also raised that sustainability for the overloaded urban ecosystem is often the focal point of many environmental problems that influence global sustainability. The sustainability agendas and liveability initiatives often meet the same environmental, equity and economic goals; as a result, their definitions overlap substantially. It is considered that one of the conditions for improved urban liveability is actually sustainability (Chivot, 2011). 8

45 While achieving liveability in cities is desirable and perhaps necessary, the goal is sometimes in conflict with the burning issues facing sustainability. Peter Newton (2012) explored the liveability and sustainability of Australian cities, while many achieved a high standard in liveability, most of them also fell short to a high level of resource consumption through both the inputs into the built environments and households. The Global Footprint Network (2012) states, the global effort for sustainability will be won, or lost, in the world cities, where urban design may influence over 70% of people s ecological footprint. With the concentration of population, economic activities and buildings, it is of no surprise that cities and buildings are at the forefront to achieve sustainability. The prominent role of cities in achieving sustainability can be demonstrated in a number of ways. As the report of WWF (2013) points out, 80% cities are responsible for as much as 80% of global greenhouse gas emissions. Taking the case of Hong Kong, according to the latest report by WWF (2013), it has an average per person Ecological Footprint of a 4.7 gha, which is much more than double of the 1.8 gha of the average global bio-capacity. In terms of categories of consumption, food and goods are major drivers for ecological footprint of Hong Kong, as it is substantially dependent on imports for all kinds of goods and food. In addition, a major portion of ecological footprint is carbon footprint. Being a city without major manufacturing industries, buildings account for about 90% of total electricity consumption in Hong Kong (HKGBC, 2012). The building sector is critically vital in steering Hong Kong towards a city of greater sustainability. Before delving deep into sustainability issues on buildings, it is crucial to realize the intricate relationship between buildings and its surroundings. This is particularly valid for Hong Kong, the development of compact high-rise built environment coupled with narrow street structures largely upsets the air circulation in the city and creates an unpleasant walking environment in the city. A study by Planning Department points out large built-up areas divorce themselves in a climatic sense from their surrounding landscape contributing to the production of a separate urban climate lie in the farreaching alteration of the heat budget and the local wind field 7. The study by the Planning Department in 2011 showed that the urban heat island effect in Hong Kong was intensifying, indicating that the temperature in urban areas was substantially higher than that in rural areas, as a result of the compact built environment and urban activities including vehicular emissions (Planning Department, 2011). Such urban heat island effect reduces thermal comfort and increase energy consumption in the urban areas. This will also discourage social activities at street level and the choice of natural ventilation of nearby buildings. More importantly, as activities take place and humans interacts in buildings and in the areas between, the social impact of the built environment must be factored into the equation of urban liveability. As Jan Gehl s famous work Life Between Buildings (Jan Gehl, 2011) pointed out, Life between buildings offers an opportunity to be with others in a relaxed and undemanding way..., in public spaces the individual himself is present, participating in a modest way, but most definitely participating. Research worldwide indicates the importance of streets for the community and also public health. The report by Civic Exchange titled Walkable City, Living Streets (Ng and Lau, et al, 2012) pointed out that Hong Kong streetscape is often characterised as a layered city where pedestrians travel along the elevated, street and underground level, such development is in opposition to good walkability and sense of community. The report also emphasised that improved walkability is crucial for richer social life and social justice. 7 Climatic booklet for urban development, as cited from Planning Department: Urban Climatic Map and Standards for Wind environment feasibility Study 9

46 Green building as a solution Buildings, as an infill to the urban fabric, affect not only the behaviour of their occupants, but also the physical attributes of the urban landscape and the sense of community. Of the 91% of the total electricity consumption, commercial buildings take the lead (65 %), followed by residential buildings (26%) (EMSD, 2012). Buildings and their users are therefore the source of the high levels of carbon emission, and yet a solution to reduce carbon emission also lies within them. If well thought out and designed, buildings can offer its residents a very high quality of life, use high density to their advantage, and reduce energy consumption effectively. Items A. Liveability Related 1. Meeting at least 50% of Hong Kong s Urban Design Guidelines, e.g. massing and intensity, height profile, view corridor, air circulation, streetscape character, circulation route, parking facilities, etc.* 1 2. Good security provisions that engender a feeling of wellbeing amongst building users % of projects achieved full scores 100% 100% 3. Achieving good interior lighting quality 100% 4. Assurance of Indoor Air Quality (IAQ), e.g. meeting Good Class of 94% to 100% IAQ Certification Scheme, reduction of odour from refuse collection chambers, providing adequate ventilation in car parks 5. Enhancing the provision of facilities for persons with a disability 94% 6. Providing amenity features that enhance the quality of life and 81% improve operation and maintenance B. High Density Related 1. Good control of noise from building equipment such as fans and 100% cooling towers 2. Healthy drainage and air-conditioning system design to prevent transmission of diseases within high-rise buildings 3. Good pollution management during construction including establishment of management plan and proper control of noise, dust and waste water 100% 94% to 100% 4. Maintain neighbourhood daylight access 88% 5. Mitigation of vibration from building services and external sources 88% C. Resource/ Environment Related 1. Use of water-efficient appliances to reduce effluent discharge 100% 2. Provision of adequate metering, adoption of proper commissioning procedures and provision of adequate manuals and training to facilitate energy use reduction 88% to 100% 3. At least 20% of materials are manufactured within 800km 94% 4. Reducing the use of ozone depleting substances 88% 5. At least 50% of timer used is from sustainable source 81% Table 1 High Score Areas of the Platinum Projects Hong Kong Green Building Council was established in 2009 to promote green building practices in Hong Kong. The Hong-Kong-based green building assessment system, BEAM Plus, offers a comprehensive assessment for buildings and embraces a wide 10

47 range of sustainability standards. Since its major overhaul in 2010, from mid-2010 to mid-2013, about 400 buildings have been registered for assessments. An analysis of the scoring patterns of the first 57 assessed projects including 16 highest-score Platinum projects was conducted. The scoring patterns of these 16 Platinum projects are also analysed separately to review the performance of the best performers. These 57 projects came from a fair spectrum consisting of commercial, residential, government, institution and community projects. For the ease of understanding, their different credit scores are divided into three categories: liveability related, high density related, and resource/environment related. Table 1 shows the common high-score areas of the 16 Platinum green buildings under these three categories. On issues related to liveability, it can be seen that BEAM Plus has led to the creation of more liveable buildings with good amenities, environmental quality, good interior lighting and sense of security. The buildings are also socially more responsible as reflected by the enhancement of universal access. In relation to the high-density urban context, the designers and builders of green buildings are particularly conscious in minimising adverse environmental impacts including daylight blockage, equipment noise and vibration, and good pollution management during construction. Healthy design of drainage and air-conditioning systems in high-rise buildings are also emphasized, possibly due to lessons learnt from SARS and earlier incidents of Legionnaires disease 8. In terms of resource and environmental impact reduction, the Platinum buildings commonly performed well in the reduction of peak electricity demand and energy management through metering, commissioning and training. They are also good at reducing effluent discharge, utilisation of locally manufactured materials, sustainable timber sources and reduced use of ozone depleting substances. Rating achieved % of projects Average % of got the rating annual energy reduction Platinum Gold Silver Bronze Unclassified 18 N/A Table 2 Energy Use Reduction among Different Classes of BEAM Plus Buildings When the analysis is extended to all the 57 BEAM Plus assessed projects, it is found that the common high score areas are similar to the Platinum projects except that high scores are not commonly achieved in the top 2 to 3 items: amenity features, facilities for the disabled, interior lighting quality, neighbourhood daylight access, vibration mitigation, reduction of peak electricity demand, local manufacturing and sustainable timber source. These represent potential areas for enhancement. In terms of annual energy use reduction, less than 25% of these 57 projects scored full marks. On average, the annual energy consumption of projects was lower than the baseline (i.e. building energy code) by 30%, 23%. 17% and 15% respectively for the Platinum, gold, silver and bronze projects (refer to Table 2). Substantial use of renewable energy is not yet common for buildings in Hong Kong, though currently there are some initiatives on using PV panels and bio-ethanol from waste cooking oil 9. It may take some time before a wider adoption could take place. 8 Further information can be obtained 9 For initiatives on renewable energy in Hong Kong, an example can be referred from Zero Carbon Building, 11

48 A report by Greenpeace on the role of BEAM Plus in reducing the average peak demand for electricity found that BEAM Plus would be a feasible solution for reducing electricity consumption (Chung, 2012). The study echoes the policy paper prepared by Hong Kong Green Building Council in 2012, HK3030 A vision for a low-carbon sustainable built environment in Hong Kong by 2030, which proposes an absolute reduction of 30% electricity use in buildings by 2030 as compared to 2005 levels. Items % of projects achieved full scores A. Liveability Related 1. Enhancing microclimate around buildings, including air 2% ventilation study, vegetation roof and light-coloured nonroof surfaces 2. Adequate (40%) greenery on site and use of pervious 7% materials for half of the hard landscaped areas 3. Conserve and protect cultural heritage 9% 4. Achieving comfort through natural lighting and natural ventilation 7% to 16% B. High Density Related 1. Impact noise isolation between floors meets IIC52 for 0% residential buildings 2. Energy efficient building form, layout and orientation 9% C. Resource/ Environment Related 1. Adopting both rainwater harvesting and grey water recycling, 0% each leading to at least 5% of fresh water saving 2. Adequate use of rapidly renewable materials (2.5% minimum) 0% 3. Adequate use of renewable energy (2.5% of energy use or 4% 100% of building footprint) 4. Adequate use of recycled content (10% minimum) in exterior 5% works, structures and interior components 5. Adequate use of prefabrication (40% minimum) 5% 6. Reuse existing buildings 8% 7. Minimising embodied energy in structural materials 11% 8. Local transport, i.e. discourage the use of private vehicles 16% Table 3 Credits Less Commonly Achieved in the 57 Projects Opportunities for enhancement Despite the encouraging results of high scoring areas of the Platinum projects, the analysis of the 57 projects also identified some areas in need of improvements i.e. full credits were less commonly achieved. From Table 3, for liveability related issues, there is room for improvement in enhancing microclimate around buildings and provision of adequate greenery on site, preserving cultural heritage, reusing existing buildings and achieving comfort through natural lighting and natural ventilation. Issues related to high density includes noise isolation between floors, passive design, energy efficient building form, layout and orientation. For credits related to resource and environment, there is room for improvement in the use of renewable energy, grey water recycling and low-energy structural materials. The high-rise nature and small footprint of Hong Kong s buildings could be one important barrier to the latter three aspects. Other pinch points of the projects include inadequate discouragement to private vehicles, recycled content in building materials, use of prefabrication and rapidly renewable materials. 12

49 Although these can be viewed as challenges to the building professionals, they also represent good opportunities for achieving greener buildings and enhancing the built environment. When the analysis is restricted to the 16 Platinum projects, it is found that their pinch points are similar to the whole population of 57 projects, except that the percentages of projects achieving the credits are a bit higher. For example, in terms of greenery on site, the percentage of projects achieving the scores is 25% for Platinum, compared to 7% in the 57 projects. Green community and neighbourhood development The analysis of the assessed projects suggested that, the performance of some aspects, like microclimate, greenery, cultural heritage, energy efficient layout and orientation, natural lighting, natural ventilation and local transport, depend not only on the design of buildings, but also the neighbourhood within which they are located. For instance, to improve the microclimate conditions and to ease the urban heat island effect, Air Ventilation Assessment (AVA) may be carried out to address the potential impact of buildings on air ventilation in the macro wind environment 10. The low scoring in microclimate suggested that the issue deserves more attention. More importantly, as microclimate around buildings is impacted by more than one single building, the urban typology needs to be considered for a genuine improvement in the surrounding area. The crux of issues lies beyond a single building, thus the area around a particular building project has to be factored in. Other issues may be the amenity provisions, urban design and quality of the public realm, and the wider social-economic factors of the whole community. As such, a stand-alone green building may not be necessarily green for the environment as a whole; a mere collection of green buildings may not result in a truly sustainable community either. HKGBC is now in the process of developing a new rating tool which embraces the high-density urban community and neighbourhood elements. One of the possible enhancements includes extending the assessment boundary beyond that of buildings to the surrounding area, so as to incorporate holistic thinking in the public realm and to place more emphasis on the open/public spaces in multi-block developments. The new tool will place emphasis on sense of place and community attributes and elements that bring building developments together into a community and relate it to the larger regional landscape. It will create a label, as well as a tool to quantify the quality of open space and urban design in a number of tangible criteria. It will serve and incentivize the creation of low-carbon sustainable communities environmentally and socially. It will encompass thoughtful neighbourhood planning which will limit the need for cars, improve connectivity and walkability, improve land use patterns, revitalise existing districts and improve neighbourhood quality, thereby creating more liveable and sustainable communities for the people of Hong Kong. The existing building stock So far much of the focus of the discussion in this paper has been on driving sustainability in new building developments. However, the majority of building stocks in 10 The Technical Circular is available at 13

50 Hong Kong are existing buildings. Improving energy efficiency and environmental performance of existing buildings will be a crucial step in making significant changes to address issues on energy reduction. From December 2012 to May 2013, the HKGBC conducted a preliminary study on the major issues of its green assessment tool BEAM Plus EB (existing buildings). Based on 14 case studies of existing buildings, the study identified those credit items that might require modification as well as a number of opinions that stakeholders expressed concerning the scheme. These issues include: an overwhelming emphasis on buildings inherent characteristics, occupants areas outside applicant s control, too much reliance on scientific analysis, disturbance to building operation during re-commissioning, inadequate scope of coverage, and the required standards not achievable for aged buildings. In response to the study, HKGBC builds on the results of this study and would commission a further consultancy to revamp the BEAM Plus EB. It is expected that the new tool may embrace an alternative path through which stepwise improvement efforts of aged buildings could be recognised. This would help the gradual transformation of Hong Kong to a greener and liveable city. There are also benefits from retrofitting existing buildings as opposed to pulling them down. Retrofitting older buildings can avoid the tremendous demolition waste and conserves the embodied energy within them. This can be viewed as a great improvement over the current weaker performance as shown in Items C6 and C7 of Table 3, i.e. building reuse and embodied energy in materials. Conclusion Like many other world cities, high-density development and living are inevitable for Hong Kong. High density has its downsides for urban liveability; it also offers opportunities for sustainability. The case of Hong Kong shows how it strikes a balance between goals of sustainability and goals of liveability in urban development. If well thought out, planned and designed, the city can use its high density to its advantage and provides its residents with high sustainability as well as liveability. The high-density compact development model of Hong Kong provides a vital learning lesson for rapidly developing Asian cities, which are facing similar challenges in economic and social development. While Hong Kong has derived high liveability from an efficient public transport system and bountiful natural assets, the city needs to strengthen its efforts in tackling air pollution, waste management, energy consumption in buildings, nature preservation, and provision of affordable housing and a steady supply of office space. While these issues are not wholly under the ambit of buildings, many issues are interconnected with them. Green building is a solution. Indeed, as indicated in the analysis of BEAM Plus assessed projects, green building assessment is useful in promoting energy efficiency. The results showed that, on average, the platinum buildings achieved an annual energy reduction of 30% as compared to code requirement. Enhancing energy efficiency and passive design in buildings can contribute to lower carbon emissions and steer Hong Kong towards sustainability. However, the substantial use of renewable energy has yet to be popularized for buildings in Hong Kong. The BEAM Plus assessment scheme has led to the creation of greener, healthier and more liveable buildings. The impact is particularly strong in regard to pollution management and indoor environmental quality. The management of pollution is of particular relevance to a high-density urban environment where construction works are often carried out in close proximity to existing buildings. Regarding indoor environmental quality, good performance is common in IAQ and security provisions, 14

51 both of which enhance the liveability of the city. In particular, for Platinum projects, indoor environmental quality is also good in terms of interior lighting, provision of amenity facilities and special facilities for persons with disability. Another aspect that Hong Kong buildings commonly perform well is the control of noise from building equipment and the healthy design of drainage and air-conditioning systems. The analysis also identified less explored areas and potentials for improvements, including the use of grey water recycling, improvement of microclimate around buildings, increased greenery on site, preserving cultural heritage, discouraging the use of private cars, use of rapidly renewable materials, energy efficient building form, recycling building materials, use of prefabrication, low-energy structural materials, reusing existing buildings, impact noise isolation between floors and achieving comfort through natural lighting and natural ventilation. All these improvements can be achieved through effective promulgation of green building assessment schemes and provision of sufficient market incentives for the key players to adopt the new building practices. BEAM Plus has its own limitations because of its parametric constraints. There is a calling to go beyond itself to embrace the public realm, the wider community and neighbourhood development. Indeed the roles and boundaries of green building must be readdressed to facilitate a more holistic and integrated approach towards both sustainability and liveability in a high-density urban context. At the same time, reducing energy consumption and raising the liveability of the large stock of existing buildings remain an onerous task. HKGBC has now embarked on these two fronts with research and development works. Together with its ambitious HK3030 Campaign and many other community programmes, HKGBC will work together with all its stakeholders - the government, both private and public sectors towards the creation of a greener, more sustainable and liveable Hong Kong. Acknowledgements The author would like to thank the Secretariats of the HKGBC for providing data. Particular thanks are extended to Ms Flora Lim and Ir Eddy Lau of HKGBC for their assistance in compiling the paper and presentation. The author would also like to thank the efforts of members of the task force on BEAM Plus Community/Neighbourhood Feasibility Study led by Mr. Larry Poon, members of the task force on Existing Building led by Mr. K M So, Prof Joseph M Chan for his valuable advice and the project owners for the use of their project information in the study and analysis. 15

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53 Environmental Protection Department Monitoring of solid waste in Hong Kong Waste statistics for 2011 [Online], available from [Accessed 8 July 2013] Gehl, J., 2011, Life between buildings: Using public space. Washington DC: Island Press. Global Footprint Network, 2012, Footprint for cities [Online]. Available from [Accessed on 10 July 2013]. Hong Kong Green Building Council (2012). HK3030 A vision for a low-carbon sustainable built environment in Hong Kong by 2030 [Online], available at [Accessed 1 July 2013]. Hong Kong Special Administrative Region Government (HKSARG) a, 2013, Factsheet Population [online]. Available from [Accessed 15 July 2013]. Hong Kong Special Administrative Region Government (HKSARG) b, 2013, Budget Speech Embracing the challenges ahead [online]. Available from: [Accessed 20 July 2013] Hong Kong Special Administrative Region Government (HKSARG) c, 2012, Factsheet Transport [Online]. Available from Accessed 15 August 2013] Hong Kong Special Administrative Region Government (HKSARG) d, 2013, Fact Sheet Country Parks and Conservation [Online] [Accessed 18 July 2013] Hong Kong Special Administrative Region Government (HKSARG) e, 2013, A clean air plan for Hong Kong [Online]. Available from [Accessed 21 July 2013]. Hong Kong Special Administrative Region Government (HKSARG) f, 2013, Policy Address Green Building [Online], Available from [Accessed 8 July 2013]. Hong Kong Special Administrative Region Government (HKSARG) g, The natural environment, plants & animals in Hong Kong [Online]. Available from [Accessed 12 July 2013]. 17

54 Hong Kong Special Administrative Region Government (HKSARG) h, Factsheet Country parks and conservation [Online]. Available from [Accessed 20 July 2013] Hong Kong Special Administrative Region Government (HKSARG) i, Composition of Long Term Housing Strategy Steering Committee Announced [Online]. Available from [Accessed 21 July 2013] Hong Kong Special Administrative Region Government (HKSARG) j, Supply-led approach long term housing strategy [Online]. Available from html [Accessed 1 August 2013] Hong Kong Special Administrative Region Government (HKSARG) k, Higher housing target tabled [Online]. Available from html [Accessed 15 August 2013] Hong Kong Special Administrative Region Government (HKSARG) l, Speech by FS at seminar on office development [Online]. Available from [Accessed 16 August 2013]. Hong Kong Trade Development Council, Economic and Trade Information on Hong Kong [online]. Available from [Accessed 19 July 2013] MTRC, Annual Report 2012 Key Figures [Online]. Available from [Accessed 15 July 2013] Newman, P., & Kenworthy, J., Cities and Automobile Dependence: An International Sourcebook. Gower, Aldershot. Newton, P. 2012, Liveable and Sustainable? Socio-technical challenges for twentyfirst-century cities, Journal of Urban Technology, 39(1), Ng, S., Lau,W., Brown, F., Tam, E., Lao, M. and Booth, V., 2012, Walkable city, living streets [Online]. Available from [Accessed on 12 July 2013]. Norman, J., MacLean, H., and Kennedy, C.,2006. Comparing high and low residential density: life-cycle analysis of energy use and greenhouse gas emissions. Journal of Urban Planning Development, 132(1), South China Morning Post a (SCMP), Delta air quality improves, but roadside pollution worse in Hong Kong [Online], available from [Accessed 12 July 2013] 18

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56 LCA MODELLING FOR BUILDING CONSTRUCTION PROCESSES Ya Hong Dong and S. Thomas Ng 1 Department of Civil Engineering, The University of Hong Kong, HKSAR 1 Corresponding Author tstng@hku.hk, Tel: (852) , Fax: (852)

57 LCA MODELLING FOR BUILDING CONSTRUCTION PROCESSES ABSTRACT On-site construction processes are complicated as they include the delivery, assembling and installation of components. Meanwhile, energy is consumed and pollutants are emitted. Although the environmental impact of construction is not as much as that of the operation and maintenance stages, it has been agreed that the emissions during the construction phase is very intensive since a large amount of work is complemented within a limited time frame. Life cycle assessment (LCA) is an effective tool that evaluates the entire life cycle of a product. Most studies attempted to investigate the upstream (i.e. the manufacturing of materials) and downstream (i.e. the operation) processes within a building s life cycle, while few models are capable of calculating the environmental impact of construction. This problem can also be found in local academy, as previous work mainly focused on building materials rather than the construction phase. Construction activities are intensively carried out in Hong Kong and China to comply with big demands for accommodation and the development of the local society. A LCA model is, therefore, desired for assessing the pollutant emissions in construction. This study develops a cradle-to-site LCA model, namely Environmental Modelling of Construction (EMoC), which accounts the environmental impact before or during construction. Localized data of concrete products, transportation, electricity, and emission factors are adopted in addition to the overseas database. A case study on a residential building project is further provided to test the model performance. While EMoC is a holistic and up-to-date model, it is likely that it can assist construction industry with decision making in the design stage. Keywords: building; construction management; environment; LCA. 1. INTRODUCTION Sustainable development was proposed by the World Commission on Environment and Development (currently Brundtland Commission) in 1987 as the development that meets the need of present without compromising the ability of future generations to meet their own needs (Brundtland, 1987). Three baseline areas are usually considered in sustainable development, i.e. environment, society and economy. Environmental problems such as climate change, ozone depletion, acidification, eutrophication, resource depletion, etc. have tremendous influence on the social and economic development. Globally, the carbon dioxide concentration exhibited an increase from the pre-industrial level of 280 ppm to 379 ppm in 2005, mainly attributed to the combustion of fossil fuel (IPCC, 2007). The rise in carbon dioxide concentration is corresponding to temperature increase, sea level rise, and snow cover decrease (IPCC, 2007). Ozone depletion caused by abundant use of halocarbon in refrigerants leads to high frequency of skin cancer apart from damaging the ecosystems. Regionally, algal blooms occur frequently in coastal waters of China, Gulf of Mexico, and fresh water systems of lakes and reservoirs. The accumulation of algae in aquatic system may destroy the ecosystem and kill the fishes and other ocean lives. Hong Kong being a coastal city was suffering from an algal bloom in 1998 leading to economic loss of HK$312 million (Dong, 2011). Other environmental issues such as a lack of landfill space and a decrease of agriculture farm are confronted by Hong Kong as well. To protect the environment, 190 countries agreed to reduce carbon emission under the Kyoto 2

58 Protocol. Local environmental protection acts also take place. For example, the China s 12 th Five Year Plan aims at a percent reduction in carbon intensity from 2005 to Hong Kong should, therefore, take opportunity to control carbon emissions, waste disposal, water quality, etc. Building and construction industry consumes a large amount of materials in the construction stage. The manufacturing of construction materials contributes significantly to environmental pollution. For instance, cement industry accounts for 5% of greenhouse gas emissions (Huntzinger and Eatmon, 2009). Other environmental impacts during construction include greenhouse gas emissions due to fuel combustion, water consumption, dust emission, resource depletion, solid waste, etc. Previous studies reveal that the environmental impact during construction is not as significant as in the operation and maintenance stage (Bilec, 2007), while the intensity of emissions due to construction is quite large since considerable work should be completed within the limited time. Rating systems such as the Leadership in Energy and Environment Design (LEED) by the U.S. Green Building Council (USGBC) and the Building Environment Assessment Method (BEAM) by Hong Kong Green Building Council (HKGBC) play a critical role in controlling the on-site environmental performance. Life cycle assessment (LCA) software programs, e.g. Athena and Eco-Quantum involve on-site processes in the assessment. Specific LCA models are developed in U.S. for on-site construction (Bilec, 2007, Guggemos, 2003). In Hong Kong, a LCA model to assess the energy consumption of commercial buildings is established (EMSD, 2006). Another study for Hong Kong context is on the LCA and life cycle cost (LCC) of building materials (HKHA, 2005). Recent construction projects have adopted precast elements more frequently. In the public rental housing projects, precast concrete accounts for 17% of the total concrete volume on average, while the adoption of precast concrete can be extended to 65% (Jaillon and Poon, 2009). Previous studies, however, have excluded the environmental performance of precast concrete elements in their LCA models. The ignorance of the use of precast concrete components may lead to inaccurate results. Furthermore, the LCA studies in Hong Kong are mostly focusing on the stages of material and operation, while the construction processes are simply included with few details or breakdowns. A holistic and up-to-date LCA model which can help evaluate environmental performance of construction is hence in lack. To bridge the knowledge gap and assist the industry to better interpret their construction projects performance, a cradle-to-site LCA model, namely Environmental Modelling of Construction (EMoC) has been developed. EMoC covers the processes occurred before or during construction from raw material extraction, through material manufacturing to on-site construction. Life cycle impact assessment (LCIA) is conducted in EMoC and a method which as received an increasing attention called ReCiPe is selected to conduct the LCIA calculation. The model provides analysis at both the midpoint and endpoint levels under the 18 impact categories. The rest of the article is structured as follows. The basic concept and recent development of LCA are introduced in the next section. Then, the model structure of EMoC is described, which is followed by a case study of a public housing project in Hong Kong. 2. LIFE CYCLE ASSESSMENT Life cycle analysis or life cycle assessment (LCA) was first implemented by Coca-Cola in 1960s to seek for alternative containers besides glass bottles. LCA differentiates 3

59 from other methods in its ability to cover a product s partial or entire life cycle. The outcomes of a LCA study may be distinct from the results of traditional analysis which focuses on certain stages, as LCA can provide a more comprehensive overview of the whole system. A LCA study is composed of four stages: (i) goal and scope definition, (ii) life cycle inventory, (iii) life cycle impact assessment, and (iv) interpretation (ISO, 2006). The first phase defines essential information for a LCA study, such as objectives, audience, study system, etc. In the second phase of life cycle inventory (LCI), model structure is established and a functional unit is defined. In terms of LCI, there are two types of LCA models: the process LCA and input-output LCA. The process LCA tracks emissions of processes within the studied system and collect data of each process. On the other hand, the input-output LCA relies on the economic input-output table in which the environmental impact is given in a sector-to-sector basis. A hybrid LCA is evolved from the process and input-output LCA as it integrates the characteristics of the two types (Bilec, 2007). The LCI result is a list of substance emissions and fuel consumption that can be used in the next phase, i.e. the life cycle impact assessment (LCIA). LCA studies can terminates at LCI without further analysis on LCIA (e.g. Guggemos, 2003). LCIA converts LCI results to various levels of results through certain calculation methods. Several LCIA methods are available, including the midpoint methods (e.g. CML, TRACI, EPD, etc), endpoint methods (e.g. Eco-indicator, EDIP, etc) and combined methods that can provide analysis in both the midpoint and endpoint levels (e.g. ReCiPe ). The midpoint methods result in values of indicators of impact categories. The endpoint methods further evaluate the damage impact caused by emissions. The calculation in LCIA is complicated with several steps to select the impact categories, as well as to derive results of characterization, normlization, and weighting. The details of the LCIA procedures are given in ISO 14040s. ReCiPe is adopted following the conclusion from a previous study (Dong et al., 2013a). ReCiPe is able to calculate results in both the midpoint and endpoint levels. Eighteen impact categories are provided in the midpoint version of ReCiPe. Characterization and normalization are available in the midpoint version. In the endpoint version, damage assessment is given at characterization, normalization and weighting. In addition, a single score is calculated to represent the total environmental performance. 3. MODEL DEVELOPMENT Environmental modelling of construction (EMoC) is designed to cover the cradle-tosite processes related to construction. The operation, maintenance and demolition stages are excluded. The model studies four groups of on-site activities, including ground work, concrete work, masonry work, and other work. The following items related to the construction activities are estimated in EMoC: material, transportation, energy, labor, equipment, and waste. Precast and cast-in-situ concrete methods are separately evaluated so that users can understand which concrete construction method is more environmental friendly. The activities and elements within EMoC are illustrated in Figure 1. The model established in Microsoft Excel composes of eleven worksheets as given in Figure 2. Users can enter data in the Input worksheet and obtain the results in the Result worksheet. Calculation is conducted in two worksheets: Concrete and Other Work. The construction activities of ground work, masonry work and other work are incorporated in the worksheet of Other Work. Background data is obtained from published research, LCI database, government report, manufacturer website, as well as field surveys. 4

60 Figure 1: Schematic illustration of the processes and elements considered in EMoC model Figure 2: Model structure of EMoC. Arrows represent data flow The LCIA results of individual products are generated from Ecoinvent database in SimaPro (a LCA software program) and utilized as background data. Materials evaluated in EMoC account for over 80% of the materials used in a general building project according to EMSD (2006). The LCI of precast concrete elements in the Hong Kong context is obtained from a previous research (Dong et al., 2013b). The emission standard can be chosen for trucks with three tiers of emissions, Euro III, Euro IV and 5

61 Euro V for various types of trucks as well as passenger cars being included in the model. Three energy types are evaluated in EMoC: electricity, gasoline and diesel. The fuel mix of electricity generation in Hong Kong is also provided in the model. For gasoline and diesel, the environmental impacts due to manufacture and combustion of fuels are separately calculated so that users can estimate the on-site emissions due to fuel combustion. The energy consumed by equipments is calculated by referring to a list of plants obtained from website of manufacturers. Three waste treatment methods of construction waste: recycle / reuse, landfill for noninert waste and public fill for inert waste have been considered in the model. Users can select if a material is recycled or not in the Input worksheet. The recycled or reused wastes are not responsible for any environmental impact as it is assumed that the impact is allocated to the next usage stage outside the system boundary. On-site dust emission is further studied in addition to the particulate emission as calculated in LCIA results in the Background Data worksheets. Users can choose from the drop-down list among the options of No control, Partially controlled and Highly controlled. The corresponding total suspended solid (TSP) value will then be provided in the Result worksheet and users can understand the dust control level of the studied project based on the results. 4. CASE STUDY The studied construction project is a public rental housing (PRH) project developed by the Hong Kong Housing Authority (HKHA). The project is to provide about 13,300 flats for 34,000 residents. The PRH project implements several green techniques, such as the reuse of marine mud, light emitting diode (LED), rainwater recycling system, precast components, etc. Precast components in this project accounts for about 35% of the concrete volume. The precast components include façade, bathroom, refuse chute, slab, etc. The environmental impact of the PRH project is evaluated in EMoC. The input data is collected through a questionnaire survey and entered into EMoC by the authors. The results are then generated in the Result worksheet of EMoC. The midpoint results are summarized in Table 1. Ng and Kwok (2013) studied the carbon emission at Kai Tak Site 1A and the value is 544 kg CO 2 eq per GFA (m 2 ). The larger value of 631 kg CO 2 eq per GFA (m 2 ) in Table 1 is due to the extra processes and materials being considered in EMoC. As the characterization value is hard to interpret, the normalization results are further provided. The normalization results are calculated as a ratio of the characterization result to intervention caused by one person in reference year. For example, a person generates about 6,891 kg CO 2 eq in 2000, thus the carbon emission of 1 m 2 GFA of the studied PRH project is equivalent to about one month emissions due to one person 1. By using the endpoint method, the single score of the project is 74 per GFA (m 2 ), mainly contributed from damage to human health (46) and resource depletion (24). 1 The value of 6,891 kg CO 2 eq per capita includes emissions due to manufacturing, construction, and other human activities that can generate greenhouse gases. Physiologically, a person generates about 1 kg CO 2 per day. 6

62 Table 1: Midpoint results of the PRH project Impact category Unit per GFA (m 2 ) Characterization Normalization Climate change kg CO 2 eq Ozone depletion kg CFC-11 eq 4.15E Human toxicity kg 1,4-DB eq Photochemical oxidant formation kg NMVOC Particulate matter formation kg PM10 eq Ionizing radiation kg U235 eq Terrestrial acidification kg SO 2 eq Freshwater eutrophication kg P eq Marine eutrophication kg N eq Terrestrial ecotoxicity kg 1,4-DB eq Freshwater ecotoxicity kg 1,4-DB eq Marine ecotoxicity kg 1,4-DB eq Agricultural land occupation m 2 a Urban land occupation m 2 a Natural land transformation m Water depletion m Metal depletion kg Fe eq Fossil depletion kg oil eq CONCLUDING REMARK A novel assessment tool namely the Environmental Modelling of Construction (EMoC) is developed to cover the cradle-to-site processes and estimates material consumption, energy usage, transportation, and waste treatment. The model is mainly based on the context of Hong Kong and China, while the coverage of regions can be potentially expanded by considering the fuel mix of electricity generation in other areas. A test case is provided in this study and the results are consistent with previous research. The advantages of EMoC include: its ability to estimate the environmental impact of the precast and cast-in-situ concrete methods; the possibility to consider several waste treatment approaches; a separate estimation on manufacturing and combustion of fuels; an utilization of local concrete inventory; a comprehensive coverage on construction materials; an analysis on eighteen impact categories; the implementation of both midpoint and endpoint methods; the implementation of newly developed LCIA method ReCiPe ; and a detailed breakdown of results. 7

63 While EMoC is an up-to-date model that provides holistic evaluation on the environmental performance of construction projects, it can be implemented in the early stage of a construction project for selecting a more environmental friendly design option. ACKNOWLEDGEMENT The authors would like to thank the Hong Kong Housing Authority for their support on this research. The financial support of The University of Hong Kong through the CRCG Seed Funding for Basic Research (Grant Nos.: and ) should be gratefully acknowledged. REFERENCES Bilec, M. M., A Hybrid Life Cycle Assessment Model for Construction Processes. Thesis (PhD), University of Pittsburgh. Brundtland, G. H., World commission on environment and development. Our common future. Oxford University Press, Oxford. Dong, Y., Analysis of stratification and algal bloom risk in Mirs Bay. Thesis (M.Phil), The University of Hong Kong. Dong, Y. H., Ng, S. T. and Kumaraswamy, M. M., 2013a. Critical analysis of the life cycle impact assessment methods. Environmental Engineering and Management Journal. (In press) Dong, Y. H., Wong, C. T. C., Ng, S. T. and Wong, J. M. W., 2013b. Life Cycle Assessment of precast concrete Units. International Conference on Civil, Environmental and Architectural Engineering, Madrid, Spain, March. EMSD, Consultancy Study on Life Cycle Energy Analysis of Building Construction. Guggemos, A. A., Environmental Impacts of On-site Construction Processes: Focus on Structural Frames. Thesis (PhD), University of California, Berkeley. HKHA, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) Study of Building Materials and Components. Huntzinger, D. N. and Eatmon, T. D., A life-cycle assessment of Portland cement manufacturing: comparing the traditional process with alternative technologies. Journal of Cleaner Production, 17, IPCC, The Physical Science Basis. Cambridge University Press, Cambridge. ISO, International Standard. In: Environmental Management - Life Cycle Assessment - Requirements and Guidelines. Geneva, Switzerland: International Organisation for Standardisation. Jaillon, L. and Poon, C. S., The evolution of prefabricated residential building systems in Hong Kong: A review of the public and the private sector. Automation in Construction, 18, Ng, T. K. and Kwok, S. M., Carbon emission estimation - a design verification tool for new public housing developments in Hong Kong. HKU-HKHA International Conference 2013, Hong Kong, 2-3 May. 8

64 PERFORMANCE BASED DESIGN: THE DESIGN ANALYSIS PROCESS Sean Quinn 1 Sustainable Design, 10 Design, Hong Kong 1 Corresponding Author squinn@10design.co, Tel: (852) , Fax: (852)

65 PERFORMANCE BASED DESIGN: THE DESIGN ANALYSIS PROCESS ABSTRACT This paper discusses a process of design guided by energy, and environmental analysis and integrated through every stage of a project s development. The goal is to create a synergy between architectural spaces and features with passive strategies and active systems through an informed loop of design, analysis, and integration of results. By quantifying energy reductions through early architectural and engineering interventions, design teams can reduce the size and operational cost of mechanical, electrical, and plumbing systems. The responsive design of architecture may enhance a project s long term performance and reduce impact on the environment. Keywords: Design Analysis, Energy Efficiency, Integrated Design, Performance Based Design. 1. INTRODUCTION Performance based design focuses design decisions on building processes and the needs of building occupants. Traditional design processes incorporate energy modeling and whole building analysis towards the completion of construction documents. The results serve primarily as a validation or invalidation of the completed design, allowing little opportunity for improvement. To enhance the performance of results, the establishment of goals, process, and decision parameters must occur early in the development of a project. Integrated design helps engage all consultants and stakeholders at early stages of a project. Whether contracts allow for this dynamic interface at early stages or not, architects have increasing responsibility to address energy and environmental factors in the conceptual stages of design projects, when the deepest impact can be achieved. From large scale master planning projects to individual buildings, these early decisions and goals can establish framework for the long term development and execution that ensures sustainability as an integral part of the project s completion. The objective of architects needs to be the maximum pursuit of passive advantages from each project s local climate and context with deep interaction with engineers, consultants, and contractors to interface their expertise and responsibilities. 2. ANALYSIS PROCESS The selection of tools, simulations, and analysis of results require a streamlined workflow to reduce repetition of modeling that can stifle forward progress. Climatic analysis, massing and orientation, energy benchmarking, façade optimization, and daylight design can be initiated from the outset of any project, enhancing the design of a building and creating early targets that can be tracked throughout the design process with whole building energy modeling (Figure. 1). These analyses are executed best with the close collaboration of engineers, allowing architects to narrow down their schemes through high-level study, providing engineers more focused deep-level 2

66 analysis on the most appropriate strategy(s). Analysis should be predominantly executed during the conceptual and schematic design phase, when there is the greatest ability to impact cost and determine functional parameters (Macleamy 2004). Figure 1. Analysis Process 3. ANALYSIS TOOLS The development of Computer Aided Design (CAD) over the past thirty years has introduced a variety of tools to design and analyze buildings. Building Information Modeling (BIM) has evolved as an attempt to increase data connection between designers, consultants, and contractors, enabling Integrated Project Delivery (IPD). There are a variety of energy and environmental analysis tools provided within the marketplace now that complement this process, though limitations are common, and the interoperability of the original model and analysis model is often complicated (Bazjanac 2011). The selection of analysis tools should be based in part on the efficiency of workflow: the ability to export from one modeling tool to an analysis tool with minimal need to refine, and minimize complete rebuilds. It is best when interoperability allows backflow such that the results of analysis can be easily integrated into the original model. While the following study describes the use of Climate Consultant, Ecotect, Vasari, Radiance, and COMFEN to assess design models created in Rhino and Sketch- Up, there are a vast array of analysis tools that may accomplish similar results (An Architect 2012). 4. METHODOLOGY 4.1 CLIMATE ANALYSIS regards the understanding of environmental factors that benefit or disadvantage a project. Figure 2 illustrates the minimum factors included in climate analysis: temperature, humidity, solar path and radiation, cloud cover, annual wind speeds/direction, precipitation, psychrometics, heating and cooling degree days. Researching the historical climatic conditions of a region provide opportunity to design in a responsive way, where environment drives form. Sustainable strategies may be identified: passive solar heat gain, natural ventilation, stormwater management, renewable energy viability, etc. Establishment of climate zone and understanding of cultural conditions will identify strategies or provide parallel references from similar international locations. A strategy applied in Hong Kong may well serve Miami, Florida, or vice versa. A historic weather file serves as the best basis for data interpretation, and the tools to be used include Climate Consultant, Ecotect, RETScreen, amongst others. 3

67 (a) Annual Conditions (b) Psychrometrics Figure 2. Climate Analysis 4.2 ENERGY BENCHMARKING & TARGETS aims to identify the average loads for existing building types in the region of a proposed project, in order to develop realistic energy reduction and efficiency goals. The Commercial Buildings Energy Consumption Survey (CBECS) provides a broad dataset of existing buildings in climate regions of the US (and through comparative climates, the world) (2003 CBECS). Analysis of major loads in each climate region will identify the principal areas for reduction across the typical dominant loads: lighting, heating, cooling, and equipment. A realistic reduction target may be formulated through goal setting with a client and brief conceptual energy modelling. Energy generation can be identified in climate analysis, so a Net-Zero gap analysis may be completed. The initial benchmark becomes a roadmap throughout the course of the project, as every energy model is compared against the initial survey data and original goal (Figure 7). 4

68 4.3 MASSING & ORIENTATION is based on a parametric approach to design, exploring different arrangements of program for functionality with response to environmental influences and constructive massings. These analyses serve to identify environmental factors and loads on site during early design schemes, including access to natural daylight per seasonal conditions (Figure 3a & b.) through shadow and insolation analysis, and cross ventilation (Figure 3c) through CFD analysis. Comparative analyses allow for the development of urban schemes or individual buildings through multiple iterations of analysis and determination of the delta between schemes. Conceptual energy analysis tools, like Vasari, IES-VE, and Sefaira allow for early understanding of building heating and cooling loads. To determine the appropriate direction of design, each model should contain only one variable, be it orientation, window wall ratio, building construction, or energy system to understand the impact (Figure 4). (a) Shadow Analysis (b) Insolation Analysis (c) Ventilation Analysis Figure 3. Massing & Orientation 5

69 Figure 4. Conceptual Energy Modeling 4.4 ENVELOPE OPTIMIZATION explores the parametric analysis of glazing areas, types, shading, natural ventilation, and daylight harvesting. Solar radiation analysis across each façade and season allows for the identification of loads (both external and internal) and areas for treatment or exposure (Figure 5a). Other analyses to consider include heat transfer, wind pressure zones, and views. The design should evolve in response to such loads, and energy performance and daylight response may be tested. An initial study should follow a local energy code as Baseline (ASHRAE or similar), with additional design schemes measured against it. Each iteration should consider façade assembly as well as window wall ratio, light trespass, and shading. Results indicate improvement or divergence across heating, cooling, ventilation, and lighting (Figure 5b)(Selkowitz 2008). Each scheme s assembly may be continuously refined until the targeted reduction is met or reason for the shortfall can be addressed. COMFEN allows multiple iterations to be processed at the same time and simple comparison of results. (a) Solar Radiation (b) Energy Optimization Figure 5. Envelope Analysis 6

70 4.5 DAYLIGHT ANALYSIS is perhaps the most common and critical study, considering how to allow broad access of natural daylight into interior spaces. Proper daylight design can limit electric light use, heat gain from both the exterior and artificial lights, and improve occupant comfort through impact on circadian rhythm. A high performance, cost-effective, comfortably daylit building requires the design team to practice integrated design (O Connor 1997). Goals for daylight can have tremendous impact on program layouts. The further into a design before considering daylight, the more challenging it will be to implement. Designing for daylight can inform plan, building massing, and other integral factors to the design of the building. Analysis allows objective measuring of the impact of daylight, including internal luminance values throughout the year, daylight factor, and daylight autonomy. Proper interpretation of such measures will help refine window wall ratio areas, glazing types, shading, and most importantly: use of space. Similar to envelope optimization, daylight design takes into consideration the massing of the building, envelope assemblies, and glazing factors. The iterative process here should illustrate which areas of a building obtain sufficient daylight to minimize electric light use without adding intense glare (Figure 6). Integration of tools like Ecotect, Radiance, and DaySim help to enable such analysis. Figure 6. Daylight Optimization 5. CONCLUSION Results of each of the aforementioned analyses allow for the continual improvement of design, but only when interpreted appropriately. After all, analysis tools function simply as calculators. The responsibility of the designers is first to formulate a proper hypothesis of the potential impacts of design measures, examine the results, and develop proper conclusions before reforming the design. Executed through a dynamic process between architects, engineers, clients, and contractors, these studies can enhance the design of projects, address performance issues early on, and be used to determine operational and economic efficiencies. When architecture incorporates the additional metric of performance, mechanical, electrical and plumbing loads may be reduced, allowing the distribution of construction costs towards the architectural features of the project. 7

71 Figure 7. Energy Benchmarking & Targets 6. REFERENCES 2003 CBECS (Commercial Buildings Energy Consumption Survey): RSEs for Building Characteristics Tables. Energy Information Administration. October, An Architect s Guide to Integrating Energy Modeling in the Design Process. The American Institute of Architects Bazjanac, V, Maile, T, Rose, C, O Donnell, J, Mrazovic, N, Morrissey, E, Well, B, As Assesment of the Use of Building Energy Performance Simulation in Early Design. IBPSA Building Simulation, Macleamy, Patrick, Collaboration, Integrated Information, and the Proejct Lifecycle in Building Design and Construction and Operation. Presented at the Construction Users Roundtable, WP-1202, August, O Connor, J, Lee, E, Rubinstein, F, Selkowitz, S, Tips for Dayilghting: The Integrated Approach. Lawrence Berkeley National Laboratory, Selkowitz, S, Hitchhock, R, Mitchell, R, Yazdanian, M, Huizenga, C, COMFEN: A Commercial Fenestration / Façade Design Tool. Simbuild

72 CASE STUDY OF DESIGN FOR NOISE MITIGATION MEASURES FOR PUBLIC HOUSING DEVELOPMENTS IN HONG KONG Rosa S.F. Lok 1 and Kenneth H.K. Wong 2 Hong Kong Housing Authority 1 rosa.lok@housingauthority.gov.hk, Tel: (852) , Fax: (852) hungkeung.wong@housingauthority.gov.hk, Tel: (852) , Fax: (852)

73 CASE STUDY OF DESIGN FOR NOISE MITIGATION MEASURES FOR PUBLIC HOUSING DEVELOPMENTS IN HONG KONG ABSTRACT Hong Kong is renowned for its high density living where we commonly find residential developments, including public housing developments, located close to roads with heavy traffic. To protect the residents in these public housing estates from noise nuisance so that they can enjoy quality living environment, the Hong Kong Housing Authority (HKHA) has applied a series of noise mitigation measures to reduce the noise impact. In general, noise mitigation measures could be applied at source, at propagation path and/or at receiver end. At-source mitigation measures include application of low noise road surfacing and construction of noise enclosures. Mitigation measures at the path of propagation including building setback, orientation and erection of noise barrier, non-noise sensitive building and vertical fin are commonly adopted. Despite these measures, where the noise impact is too severe for these mitigation measures to be adequate, we need to develop more innovative building design particularly for difficult public housing sites in order to achieve flat production target. Such innovations will bring improvements to the building efficiency and enhance the built environment. In this paper, we share our experience in research and development of innovative building design for the public housing developments to mitigate noise problem. We also give an account on how the noise challenges are tackled by making use of recent projects, including site layout, building disposition, special flat configurations, plus innovative design such as acoustic balcony and acoustic window. Full collaboration amongst stakeholders is essential to develop and formulate the best noise mitigation solution. This paper also illustrates how effective collaboration enabling innovative designs can help improve the quality of the urban living environment. Keywords: Acoustic Balcony; Acoustic Design; Acoustic Window; Innovation; Noise Mitigation. 1. INTRODUCTION Under the land use planning mechanism, HKHA as the developer needs to conduct noise assessments to ensure its public housing developments comply with the requirements of the Hong Kong Planning Standards and Guidelines (HKPSG) and the Noise Control Ordinance Cap. 400 (NCO). During the preparation of planning brief, HA needs to demonstrate effective noise mitigation measures in the design of new public housing developments to the satisfaction of Environmental Protection Department (EPD). Many public housing sites are subject to severe noise impact from various sources including heavily trafficked roads, railways, public transport interchanges, depots and mechanical plant at industrial/commercial buildings. In particular, some of these sites require rezoning and we need to prove the environmental acceptability of the sites from the perspective of noise compliance. To mitigate noise impact and meet the requirements of relevant ordinances and guidelines, we apply a number of passive design measures ranging from the use of single aspect design, optimized block disposition, non-noise sensitive buildings such as multi-storey carpark or commercial building acting as noise barrier, podium, architectural fin and noise barrier in our developments. While each measure has its own merits and demerits, site constraints often restrict their full application, and more innovative measures are required at particularly difficult sites. In recent years, we have carried out research and 2

74 development on innovative mitigation measures and explored practicable approaches with our stakeholders in resolving the noise issues for our developments. 2. ASSESSMENT CRITERIA AND NOISE CONTROL STANDARD HKPSG sets out the road traffic noise standards whereas the railway noise and industrial/commercial noise are controlled under the NCO. The noise standards are summarized as follows (a) (b) (c) For road traffic noise, the assessment criteria are stipulated in the HKPSG which provides a set of standards applicable to different land uses, ranging from 55dB(A) to 70dB(A) with the noise standards for (i) domestic premises, hotels and offices at 70 db(a), (ii) educational institutions at 65 db(a) and (iii) hospitals and clinics at 55 db(a); For railway noise and fixed noise source from industrial/commercial premises, statutory standards under the NCO range from 50 db(a) to 70dB(A), depending on the background noise of the area, the nature of land use in the vicinity and the time period (day, evening or night) under consideration; and For other specific noise source including bus depots/termini, wholesale markets and container terminals, it is required under HKPSG to consider during planning stage the location of these facilities so that there is no line-of-sight of the noise sources from the noise sensitive receivers or provide screening to the noise sources. 3. NOISE MITIGATION MEASURES There are three generic types of noise mitigation measures to protect the noise sensitive receivers from the noise impacts, namely (a) mitigation measures at source, (b) mitigation measures at path of propagation, and (c) mitigation measures at receivers. 3.1 MITIGATION MEASURES AT SOURCE AND AT PATH OF PROPAGATION In general, mitigation at source and at path of propagation is the most effective way for easing the noise problem. The choice of suitable mitigation measure at source depends on site constraints and the required acoustic performance for individual housing project. These include the following: OFF-SITE NOISE BARRIERS FOR ROAD/RAILWAY NOISE Off-site noise barrier to mitigate the noise impact have been used for many public housing projects. Such barrier takes up ground space especially for heavy structure which may pose great constraint in tight site. A noise barrier reduces noise by interrupting the propagation of sound waves towards the sensitive receivers. For effective functioning, the barrier should be able to prevent the line of sight between the receiver and the noise source such that the receiver falls behind the acoustic shadow zone of the noise source. Examples of noise barrier used in recent public housing projects include construction of off-site noise barriers at public road at Tuen Mun Area 54 Site 2, and construction of a track side noise barrier to abate the railway noise at Tung Chung Area 56 which abuts directly the Tung Chung railway line (Figure 1). 3

75 Figure 1: Trackside Noise Barrier for Tung Chung Area 56 Public Housing Site MITIGATION MEASURE AT FIXED NOISE SOURCE Upon rezoning of the potential public housing site for residential use, any fixed noise such as the noise generated from mechanical plant in its proximity cannot be tolerated. The resolution of the noise problem is required for the successful rezoning of a site for residential use. Acoustic mitigation measures at source are most effective to mitigate the fixed plant noise. In such circumstances, acoustic enclosure and louvers were installed to shelter the existing chiller plant and cooling towers at the roof of a commercial building which is located close to the public housing development and we need to engage the owners of these fixed plant for the installation of the at-source mitigation measures NOISE COVER FOR PUBLIC TRANSPORT INTERCHANGE (PTI) A number of our public housing sites are located very close to PTIs. Noise barriers are sometimes not effective to block the line-of-sight to meet EPD s requirement for avoiding line-of-sight of the noise source at the PTI. Noise cover has to be used instead to abate the noise. To avoid the use of mechanical ventilation and fire services installations which will increase the future maintenance costs, we especially design the deck cover punctuated with openings at suitable spacing and orientation. These PTI with special noise cover could be constructed together with the public housing project, and handed over to the Government for management and maintenance upon completion. Examples of these are the construction of the PTIs at Hung Shui Kiu Area 13 and Shui Chuen O public housing developments (Figure 2). Figure 2: Noise Cover for PTI at Hung Shui Kiu Area MITIGATION MEASURES AT RECEIVER While noise impact is more effectively mitigated at locations of noise sources, there are circumstances where at-source mitigation measures could not be practicably implemented for reasons such as lack of space for noise barrier erection. Hence, mitigation measures at receiver end need to be considered to overcome the noise 4

76 impact. These measures are based on three types of acoustic principles screening, setback and reducing view angle. Taking into account the site conditions and configuration, the building blocks may be designed to set back away from the noisy roads and at a screwed angle to the noise source as far as possible to reduce the noise impact on the building façade. Sometimes, vertical fins walls may also be added adjacent to windows to reduce the view angle towards the noisy roads, thus lower the noise levels at the flats. Single aspect building design with non-sensitive receivers, such as kitchen and bathroom, facing against noise sources could be a very effective measure to solve severe noise issues. However, single aspect is not an efficient building design and it is not suitable for use at sites having a pleasant view toward the direction of noise source. After all, indirect mitigation measure in the form of window insulation and air conditioning could be considered as the last resort, despite it would deprive the enjoyment of natural ventilation for achieving a quiet environment. Apart from the above traditional noise mitigation measures, we have recently developed more innovative measures at receiver end for mitigating road traffic noise in order to fully utilize the site development potential and to improve the living environment. These are described in details as follows. 4. INNOVATIVE MITIGATION MEASURES 4.1 ADOPTION OF SITE SPECIFIC MODULAR FLAT To suit site constraints, public housing projects sometimes have to use site specific modular flat design to achieve self-screening effect for traffic noise. Subject to the compliance of the Building Regulations, the environmental performance can be enhanced by repositioning the windows in tailor-made flat layout. The site-specific modular flat design was first adopted in the Ex-Cheung Sha Wan Police Quarters public housing site. This design has further been used in the Tuen Mun Area 54 Site 2 public housing site, in which fixed windows are positioned at protruded rooms facing major traffic noise source and openable side windows are provided with lower noise impact to meet the noise standards. These protruded rooms could also reduce the view angle of the adjacent recessed rooms for noise protection. A comparison of a typical layout of this site specific modular flat with standard modular flat is shown at Figure 3. Such specific design can ameliorate noise impact by 2 to 3 db(a). In the use of this design, various operational factors including field of vision, ventilation, natural lighting, and window cleansing requirements have to be carefully considered. 4.2 ARC-SCREEN BALCONY Figure 3: Site Specific Modular Flat against Standard Modular Flat The proposed Sai Chuen Road public housing development in Sham Shui Po is exposed to severe road traffic noise impact due to the heavy traffic at the West 5

77 Kowloon Corridor at some 35m away from the site. Although Y-shaped block design was adopted to reduce the view angle to the West Kowloon Corridor and provide some self screening effect, initial road traffic noise assessment indicated that the unmitigated case would achieve a noise compliance of only 46% and a maximum noise level of 78dB(A). Due to the site and road configuration, other conventional noise mitigations such as building setback, fins and barriers etc., are not practicable. In order to alleviate the noise problem, the project team came up with an innovative arc-screen design for shielding noise impact in front of the windows. Desktop numerical analysis was then conducted to investigate its noise mitigating effect. After reviewing the findings with EPD, it was considered necessary to verify the effectiveness of the measure and evaluate its in-situ noise reduction effect by on site measurement using prototype installation. In mid 2008, a 3-storey full scale model prototype installation was constructed at Dongguan in Mainland China, simulating the development s configuration for the in-situ noise measurements. In collaboration with EPD, various arc screen options using different materials and testing scenarios have been worked out for testing. A total of about ten thousand acoustic measurements have been taken in the Dongguan model (Figure 4). Testing results indicated the effectiveness of noise attenuation by the arc screen for use in the project. Figure 4: Mock-up Model at Dongguan and Measurement Scenarios Upon further consultation with various stakeholders, this arc screen design concept finally evolved in the form of an acoustic balcony. The original arc-screen design concept and the final balcony design are shown in Figure 5. Figure 5: Arc Screen Design Concept and Final Acoustic Balcony Design 6

78 Together with the application of noise absorption linings at the balcony, the balcony could achieve noise reduction up to 6.4 db(a) for the proposed development at Sai Chuen Road. With the provision of the balcony structure together and other mitigation measures, the noise compliance rate was significantly improved to 90% and the maximum noise level was reduced to 75 db(a). Upon completion of this development, in-situ noise measurements would be conducted at the completed housing blocks to ascertain the noise attenuation effectiveness at as-built floors. 4.3 ACOUSTIC WINDOW For sites close to very noisy roads such as San Po Kong public housing development which abuts Prince Edward Road East, even balcony structures would not be sufficient to abate the noise impact. To support the rezoning, EPD requested for 100% noise compliance with the HKPSG s requirement of 70 db(a) for traffic noise impact. Due to the heavy traffic flow at Prince Edward Road East, the unmitigated noise level at the site boundary was anticipated at 85 db(a). Practicable traditional measures could provide a noise reduction of 7 db(a) and the project team needed to work out some innovative measures to further attenuate 8 db(a) in order to enable the project viable. In collaboration with EPD and the Hong Kong Polytechnic University (HKPolyU), the project team looked into the design of acoustic window, which function as a modified double-glazed window with offset openings to allow natural ventilation (Figure 6). In mid 2009, we commenced our exploration by conducting laboratory test on this window design concept in the laboratory of HKPolyU. The purpose of this laboratory exploration was to verify the sound attenuation performance of the window system and how the performance would be affected by other parameters including configuration of the window pane and opening, separation of the panes, angle of sound incidence and use of sound absorption material in the window system. Figure 6: Configuration of Acoustic Window System A total of 20 nos. window casement design and over 200 testing scenarios with noise source variations of line sources and point sources have been carried out in the laboratory testing. Test findings indicated that the acoustic window system should be capable of mitigating noise with attenuation up to 8 db(a). Further to the laboratory exploration, detailed assessment had to be undertaken to evaluate the sound attenuation which could be applied to the proposed acoustic window sets to be installed in the housing project. After much deliberation among HKHA s project team, EPD and HKPolyU s experts, it was considered that the effective sound attenuation of the acoustic window should be established by direct comparison of its performance against that of conventional window under in-situ noise environment. Full scale mock-up flats installed with prototype acoustic window was subsequently set up at San Po Kong site to facilitate in-situ acoustic measurements (Figure 7). 7

79 Figure 7: Photos and Layout of Mock-up Flats A total of 34 nos. of microphones were employed to measure simultaneously the exterior and interior noise levels of the mock-up flats under 20 flat/window scenarios during peak hours of traffic. Upon testing for different scenarios, it was established that the acoustic window with noise absorption materials at the window frame could achieve noise attenuation up to about 8 db(a). With the use of acoustic window and other noise mitigation measures, 100% noise compliance with HKPSG requirement can be achieved for the housing project to proceed. Besides meeting the noise requirement, compliance of the window design under the Buildings Ordinance is equally necessary, either in terms of openable window parts in the glazing area or achieving minimum ventilation rate of 1.5 air change per hour, when the inner sliding window is at closed position behind the opened window in front. On top of all these criteria, other operational factors in the use of this window system like window cleansing, clothes drying requirements and long term maintenance have to be carefully considered. 5. COLLABORATION WITH EPD AND OTHER STAKEHOLDERS Over the years, HKHA have been working in close collaboration with EPD and other stakeholders of expertise such as environmental consultants and tertiary educational institutes in the exploration of various innovative measures to mitigate noise impact to our public housing developments. During the research and development of acoustic balcony and acoustic window, EPD gave valuable advice on the knowledge and experience in similar research projects together with the regulatory requirements of noise control whereas the environmental consultants and tertiary educational institutes were capable of providing acoustic expertise in the investigation and testing. HKHA being the project proponent are better familiarised with the design, construction and operation aspects and have undertaken the project manager and designer roles of these innovation projects. Experience demonstrated that such collaboration approach with other government departments is essential and practicable to develop innovative measures for the benefit of the community. HKHA welcome collaboration with other stakeholders of construction industry to explore innovations and to share and exchange the experience gained during the research and development processes. 6. CONCLUSION Given the high density urban setting in Hong Kong, it has been a great challenge in striving for a healthy and sustainable living environment against various pollution sources, with noise being one of the major pollution impact. Over the years, through close collaborations among stakeholders in the academic institutes, regulatory authority and construction industry, HKHA have successfully developed various innovative noise mitigation designs and measures for optimizing the development potential of the public housing site and for improving the built quality of the housing development, with the results that more restricted sites can be productively used for the benefit of Hong Kong as a whole. 8

80 A Holistic Strategy to Extend Service Life of Aged Buildings Ir S.T. Chan 1 Ir Danny K.C. Chung 2 Ir Bosco L.K. Au 3 Ms Winnie W.Y. Lo 4 Ir Stanley T.K. Ng 5 The Hong Kong Housing Authority, Hong Kong st.chan@housingauthority.gov.hk, Tel: (852) , Fax: (852) kc.chung@housingauthority.gov.hk, Tel: (852) , Fax: (852) lk.au@housingauthority.gov.hk, Tel: (852) , Fax: (852) wy.lo@housingauthority.gov.hk, Tel: (852) , Fax: (852) stanley.ng@housingauthority.gov.hk, Tel: (852) , Fax: (852)

81 A Holistic Strategy to Extend Service Life of Aged Buildings ABSTRACT Hong Kong is a crowded city with over seven million people living in an area of 1100km 2. The Hong Kong Housing Authority (HKHA) is the major government institution responsible for constructing public housing as well as maintaining its housing stock of 730,000 units. The public housing is now home for over 2 million people since its first development 60 years ago. With an increasing number of public rental housing buildings approaching 40 years old, the HKHA is facing a major challenge in sustaining its aged housing stock to meet the needs of tenants with heightened expectations. In 2005/06, the HKHA launched a holistic strategy, embracing the Total Maintenance Scheme (TMS), the Comprehensive Structural Investigation Programme (CSIP), and the Estate Improvement Programme (EIP) with the purpose of enhancing sustainability of its buildings using pro-active, systematic and customer-oriented approaches. The TMS features proactive in-flat inspection in five-year cycles, prompt repair and education for tenants to prevent minor repair issues from blowing up into major problems. The CSIP aims to identify the root causes of structural defects, examines the vulnerability of structural elements, and forecasts the long-term structural health of aged buildings. Based on the investigation results, tailor-designed repair solutions are established to extend the service life of aged buildings for at least 15 years. Following the CSIP for an estate, an EIP is implemented to execute the proposed structural repairs together with facility improvements to address demographic changes and growing demands of the estate community. Indeed, the holistic strategy since its inception has been proven to be a success in extending the service life of aged buildings while meeting the sustainability challenges on environmental, economical, and social fronts. Keywords: Building Service Life; Building Sustainability; Total Maintenance Scheme (TMS); Comprehensive Structural Investigation (CSIP); Estate Improvement Programme (EIP). 1. BUILDING SUSTAINABILITY Sustainability is the ability to meet today s needs without compromising those of subsequent generations. For the past decade, a high level of research interest in green buildings has spawned notable environmental advances on all fronts including design philosophy, construction methodology, and energy efficiency. Many of the advances have been put into practice today by the building industry resulting in innovative buildings with lower carbon footprints and enhanced sustainability. While the industry is heading in the right direction, building sustainability cannot be truly achieved without a holistic strategy in extending the service life of existing buildings. In fact, in a highly developed city like Hong Kong, the number of newly completed residential flats in 2012 was only 19,900 units, which represents less than 1% of the 2.6 million residential flats of all types in Hong Kong (Census and Statistics Department, 2013). Even under an aggressive public rental housing (PRH) production plan, the target production of the Hong Kong Housing Authority (HKHA) is about 79,000 flats from 2012/13 to 2016/17, which corresponds to only about one-tenth of the existing 2

82 PRH flats. With 30% of the PRH buildings approaching or already over 30 years old, the HKHA is facing a major challenge in upholding the quality of its existing housing stock to meet tenants needs. Considering the heavy drain of manpower and financial resources resulting from mass redevelopment of aged buildings, the HKHA is now focusing on a strategy of extending the service life of aged buildings in a sustainable manner under three key initiatives: the Total Maintenance Scheme (TMS), the Comprehensive Structural Investigation Programme (CSIP) and the Estate Improvement Programme (EIP). 2. SERVICE LIFE OF PRH BUILDINGS The overall service life of a building is characterized by the time limit at which the required operating qualities can be adequately served by the building. The time limit is governed by the lesser of the physical or obsolescent service life. For a PRH building, physical service life ends when the building degrades to a point when its structural integrity is no longer economically viable to maintain. On the other hand, obsolescent service life for a PRH building is defined by the time when the building ceases to meet the living needs of tenants. 2.1 CHALLENGES IN PHYSICAL SERVICE LIFE Public housing in Hong Kong has a long history tracing back to the early 1950s. Today, the HKHA is managing 1,170 buildings in which 18% were constructed in or before the 1970s and 44% were constructed in or before the 1980s. Notwithstanding a series of comprehensive maintenance programmes, aging is still the single most important factor in the structural deterioration of PRH buildings. Besides the normal aging process, other macro and micro environmental factors play a significant role in the physical service life of PRH buildings. In terms of macro environmental factors, Hong Kong is a hot and humid coastal city. Effects of the coastal environment, high temperature, high humidity, and acid rain all increase the risk and rate of steel corrosion. In terms of local factors, problems in early design result in low maintainability and high susceptibility to environmental attacks. As the maintenance needs for many of these early PRH buildings became unsustainable, a massive redevelopment programme was initiated in the 1970s in order to completely redevelop these buildings. Considering the significant environmental impacts of complete redevelopment, the HKHA is now proactively addressing the root problems of structural deterioration in prolonging the physical service life of its aging housing stock with new techniques and solutions. 2.2 CHALLENGES AGAINST OBSOLESCENCE As important as the physical condition of PRH buildings, their built environment and facilities must be well kept to meet the rising expectations and changing needs of tenants. Certainly, the tenants expectations in the 1950s for the early seven storey walk-up blocks in Shek Kip Mei Estate were very different from the tenants expectations in a PRH estate today. Long gone was the time when tenants shared communal toilets and cooked in public corridors. With improved social and economical conditions in the 1970s, these early design soon became obsolete and undesirable in Hong Kong. The massive redevelopment programme undertaken since the 1970s replaced these older blocks with self-contained units each equipped with an in-flat kitchen, a bathroom and a balcony. Space allocation, ventilation design and daylight penetration have all been enhanced to meet the demand for a better quality of life. However, with a low birth rate and longer life expectancy in Hong Kong, the tenant age profile is changing gradually. With an elderly population of 23% in the PRH community 3

83 today, the HKHA once again is required to reinvent its PRH estates so that the built environment and facilities would address the tenants needs at every stage of their lives. 3. THE HOLISTIC STRATEGY FOR BUILDING SERVICE LIFE EXTENSION A holistic strategy for building service life extension is a comprehensive strategy that addresses the physical and obsolescent challenges in building service life. To extend the service life of aged PRH buildings, the HKHA adopts a holistic strategy that includes three key initiatives: TMS, CSIP and EIP, which together satisfy the three broad principles (Figure 1) of sustainability as follows: Social TMS - Improving tenants satisfaction through customer-oriented repair service CSIP - Minimizing nuisance to tenants through innovative repairs EIP - Enhancing living environment for all ages through improved facilities HKHA s Holistic Strategy Bearable Equitable Sustain able Environmental Economical TMS - Preventing the need of extensive repairs through timely maintenance CSIP - Delaying redevelopment through service life extension EIP - Saving energy through energyefficient designs and facilities TMS - Stopping further deterioration through proactive action CSIP - Lowering life cycle cost through effective & durable maintenance EIP - Allocating funds effectively through addressing key concerns of tenants Viable Figure 1: HAHK s Holistic Strategy in Building Sustainability: TMS, CSIP, EIP 3.1 TOTAL MAINTENANCE SCHEME (TMS) The HKHA adopts a cyclic maintenance strategy in taking care of its housing stock. With the heart of providing quality housing to low-income families in a sustainable manner, planning of maintenance commences at the design stage of a new building. Selection of materials and installation methods are carried out with due consideration of future maintenance needs. Implementation of planned and routine maintenance of PRH blocks is initiated once a new building is completed. In taking a bold step forward, the HKHA launched the TMS in 2006, which is a comprehensive, proactive and customer-oriented programme for tenants in a bid to prevent minor repair issues from blowing up into major problems. The TMS adopts a three-pronged approach in the delivery of maintenance services in five-year cycles, namely, (i) proactive identification of maintenance problems, (ii) prompt response to tenants requests for repairs and (iii) enhanced publicity and education to tenants. Rather than reacting to complaints or requests for repairs, in-flat inspection ambassadors trained under the TMS visit individual households and carry out in-flat condition surveys. With a computerized system developed to support the TMS, inspection findings are recorded on personal digital assistants (PDAs). On-the-spot repairs are carried out for minor defects while 4

84 works orders are issued with PDAs for prompt rectification of more complex problems. To strengthen communication with tenants, a maintenance hotline supported by a call centre has been set up to handle calls concerning inspection appointments, complaints and enquiries. Regular reports are generated by the computerized system to facilitate monitoring of appointments and repair services. With the computerized system storing inspection survey results and repair records, a comprehensive database has been developed facilitating traceability and in-depth analysis for review of future maintenance strategy. Making good use of in-flat inspection opportunity, TMS ambassadors also educate tenants on the proper use and maintenance of the fittings and facilities provided in their flats. To cultivate a customer-oriented service culture, seminars and workshops for experience sharing to maintenance contractors are arranged. Regular meetings are also held with the Estate Management Advisory Committees, District Council members and tenants to report work progress and collect feedback. To promote awareness and values of the TMS, a Maintenance Education Centre and various Mobile Maintenance Education Booths are set up for tenants with display boards, videos corners and mockup demonstrations of building components. Promotional videos of proper home maintenance featuring celebrity icons are also broadcast at prominent estate areas. The TMS is a successful maintenance strategy that addresses environmental, economical, and social aspects of sustainability. Environmentally, there are benefits in terms of enhanced physical service life while minimizing major repairs. Economically, the life-cycle repair cost can be reduced by proactively identifying and eliminating minor problems from blowing into major issues. Furthermore, the real on-going TMS cost is anticipated to be lower in the next 5-year cycle as most of the problems would have been addressed in the first time. Socially, with timely rectification of defects, tenants can enjoy a better living environment, which has been proven by a tenant satisfaction rate of over 80% since the launch of the TMS. 3.2 COMPREHENSIVE STRUCTURAL INVESTIGATION PROGRAMME (CSIP) Launched in 2005, the CSIP is implemented for estates approaching 40 years of age and at a 15-year interval afterwards. The CSIP systematically and thoroughly probes into structural conditions of aged PRH buildings and determines whether they are structurally safe and economically viable to maintain. Based on the Comprehensive Structural Investigation (CSI) results, tailor-designed repair solutions are established to extend the service life of aged buildings for at least 15 years. Previous findings revealed that deterioration to buildings in these estates varies significantly in both extent and severity. While visible defects of older buildings usually draw the most attention, there were cases of visually sound members in younger buildings concealing an advanced level of rebar corrosion. As a result, a timely CSI coupled with a tailordesigned repair strategy are crucial for the physical service life extension of PRH buildings. The six major steps for a typical CSI are described below: i) Desktop Study A desktop study for a new CSI involves the study of records including repair history, record drawings, design calculations, past structural appraisals, and previous improvement/strengthening records. Elements that previously required substantial or repeated repairs are one of the main focus areas in the new investigation. ii) Visual Survey 5

85 A visual survey is conducted to cover all common and external areas. However, visual inspections to occupied flats could be considered as nuisance by some tenants. As a result, a representative sampling approach (e.g. a 5% inspection rate for occupied flats) is necessary to balance accuracy with the level of disturbance. Where the level of deterioration varies significantly due to differences in workmanship, usage and performance, a higher inspection rate is used to gain a deeper insight into the deterioration extent and severity. Repair records are retrieved and tenants are also interviewed in order to obtain a better picture on the history of defects and repairs. Besides documenting all visible defects on structural elements, the aim of a visual survey is also to identify symptoms and clues which would characterize underlying structural degradation processes. iii) Testing Based on the information gathered from the desktop study and visual survey, a test programme is devised in order to diagnose the in-depth conditions of structural elements and confirm the root causes of defects. Destructive tests include rebar corrosion measurements, concrete core compression tests, carbonation depth measurements, and chloride content analysis. To minimize disturbance to tenants, destructive tests are mainly conducted in common areas and vacant flats only. On the other hand, non-destructive tests are carried out at common areas, vacant flats, as well as in occupied flats. These tests include concrete moisture content measurements to locate the source of water seepage; concrete void detections to examine delamination and spalling; half cell potential tests to assess corrosion risks; and corrosion current surveys to quantify reinforcement corrosion rates. iv) Physical Service Life Assessment Adopting the concept of a reversible limit state as defined in EN 1990:2002 (BSI 2002), a structural defect is considered to be an acceptable defect when it can be repaired economically and reversed if appropriate action is taken. On the other hand, a building with structural defects that cannot be economically restored or repaired is considered to be beyond the reversible limit state and would represent the end of its physical service life. As a result, the aim of a CSIP physical service life assessment is to facilitate the development of a repair scheme that is effective in extending the service life of an aged building in a sustainable manner as illustrated in Figure 2. Figure 2: Physical Service Life Extension of PRH Buildings 6

86 Cumulative Frequency of Samples (%) _ Sustainable Building 2013 Hong Kong Regional Conference With sufficient data collected from a well devised testing programme, a physical service life assessment could be carried out as follows: - Appraise the residual capacity of various structural elements and assess structural stability based on current structural conditions; - Evaluate the severity, extent and nature of deteriorations. Establish the causes and mechanisms of deteriorations and assess factors which could have significant effects on the degradation process such as concrete cover depths, screeding thicknesses and material strengths; - Estimate future deterioration rates for various groups of structural elements based on condition survey data, existing chloride contents, carbonation depths, and current corrosion rates. Particular attention should be given to the effects of various repair schemes on future deterioration rates. - Assess structural stability and appraise the residual capacity of structural elements with proper maintenance. Based on the CSIP experience, vertical structural elements typically govern the building residual service life as the restoration cost on walls and columns extensively deteriorated is prohibitively high. As a result, using the predicted corrosion rates for vertical elements, the likely residual period of time before steel corrosion reaching the minimum acceptable level can then be predicted at 90% probability. An example of the residual physical service life modeling result for a building maintained under the holistic strategy of the HKHA is illustrated in Figure % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% At present, 90% of vertical element samples have less than 18% of SAL. at present (CSIP) after 10 years after 20 years after 30 years after 40 years after 50 years after 60 years Steel Area Loss (SAL) % Building Estate E, E, with with steel a calculated SAL reserve of reserve 30%, can of 30%, has enjoy a residual a period physical of 59 years service life before of 59 steel years if properly corrosion will maintained. affect the global safety. Figure 3: An Illustrative Example of Physical Service Life Modeling for Building E v) Preventive and Repair Schemes for Physical Service life Extension According to a survey done by the CONREPNET team (Matthews et al., 2007), only 50% of the structural repairs can be regarded as successful because of incorrect repair design, wrong diagnosis of root causes, underperformed repair materials, and poor workmanship. In fact, the remaining 50% were considered as successful in terms of works quality only. When the repair time and cost are considered, an even lower success rate is anticipated. As the holistic maintenance strategy of the HKHA is placing more and more emphasis on human and sustainability aspects, another key factor, which is as important as the cost, time and quality, in determining the final 7

87 success of a repair work is tenants perception. Tenants, as the receivers of service, may not understand the long term quality or cost of a repair. Rather, they care more about how a repair is handled, how disturbing (e.g. dust, noise, duration, frequency) is the repair, and whether workers are punctual and polite. Understanding the challenges of implementing a successful repair scheme, various sustainable and customeroriented repair techniques have been adopted and developed under the CSIP as illustrated in Table 1: Repair Principles Protection against water ingress Structural restoration / strengthening Improving microenvironment Table 1: Repair Techniques Developed and Adopted under the CSIP vi) Performance Monitoring Techniques Developed and Adopted under the CSIP - Anti-carbonation paint coating to delay carbonation and prevent corrosion - Waterproofing with polyurea to stop water seepage without substrate demolition - Multi-pulse sequencing system for stopping basement leakage - Concrete restoration with high performance concrete (properties: low permeability, high workability, early strength gain, good compatibility with existing concrete) - Stitching of movement joints to improve load carrying capacity - Use of hydro-scarification for concrete/screeding demolition with minimal disturbance to tenants - Use of galvanic sacrificial anodes to extend service life of repair - Converting façade grill-block walls into solid walls to eliminate water ponding problems - Providing eaves as rain-shelter to reduce rain penetration - Installing pipe plinths to stop water leakage at pipe piercing locations - Removing non-structural elements prone to deterioration to reduce frequency of repairs The CSIP is always about getting better by accumulating experience. In achieving this objective, long-term performance monitoring has been implemented to improve the future maintenance strategy. The monitoring includes visual surveys, moisture surveys, non-destructive tests, tenant interviews, and statistical analysis of maintenance requirements before and after repairs. Based on the monitoring results, adjustments and enhancements can be made to the formulated strategy with due considerations given to the environment, life-cycle cost, and disturbance to tenants. 3.3 ESTATE IMPROVEMENT PROGRAMME (EIP) With the physical service life being addressed by the CSIP, the obsolescent service life of an aged PRH estate is extended through the implementation of an estate-specific improvement programme, i.e. EIP. The aim of an EIP is to upgrade the provisions and facilities of an aged PRH estate so that it can continue to provide tenants with a decent living environment while meeting their up-to-date needs. Rather than taking a facilitybased approach, a people-first and activity-based approach is adopted in the EIP design for better community bonding. During the conceptual stage, key concerns of a particular estate are identified through tenant surveys and EMAC consultation. Demography and unique estate features are studied and analyzed for a sustainable improvement scheme focusing on people. In particular, common areas and nondomestic premises are redesigned to suit tenants changing needs stemmed from the aging tenant profile. Recreational facilities (e.g. fitness equipment for the elderly) are enhanced to cater for different age groups and public space is reshaped to promote 8

88 social interaction. Weather-protected passage and barrier-free access such as new lifts and ramps are integrated into a master pedestrian network to improve pedestrian circulation with the needs of the elderly and disabled tenants in mind. External façades and public areas are face-lifted to provide a pleasant living environment while in-flat facilities such as grab rails are fixed inside bathrooms for elderly tenants. Environmental concepts are incorporated for greener and more energy-efficient designs. For instance, provision of green roofs on top of low-rise plant houses and non-domestic buildings can reduce indoor heat gain and at the same time improve the environment of a neighbourhood. Energy saving initiatives, such as energy-efficient corridor lighting are put in place. Aging building service installations are also gradually replaced and modernized with a comprehensive programme to lower the total life-cycle cost. Energy-efficient lifts are installed under the Lift Modernization Programme, which enable a reduction of energy cost by over 30% when compared to the existing ones. Indeed, by adopting a people-first and activity-based approach, the EIP is able to rejuvenate the community, forge stronger ties in the neighbourhood, and extend the obsolescent service life of PRH estates. 4. CONCLUSIONS The HKHA is committed to provide affordable quality housing and maintenance to meet the needs and expectations of its tenants. With the aging of its tenants along with its housing stock, the HKHA is reinventing its aged estates through the three key initiatives: TMS, CSIP, and EIP. While the aim is to extend the physical and obsolescent service life of aging PRH buildings in a sustainable manner, HKHA s holistic maintenance strategy is always centered on people. With the tenants at heart, all repairs and upgrades are customer-focused, addressing key concerns and needs of tenants while keeping disturbance and nuisance to a minimum. Indeed, the HKHA is proud to say that the holistic strategy is a success in extending the service life of aged buildings while meeting the sustainability challenges on environmental, economical, and social fronts. 5. REFERENCES BSI, BS EN 1990:2002 Eurocode Basis of structural design. British Standards Institute. Census and Statistics Department, Hong Kong Statistics [online]. Available from: [Accessed 12 June 2013]. Matthews, S.L., Sarkkinen, M. and Morlidge, J.R., Achieving Durable Repaired Concrete Structures: Adopting a Performance-based Intervention Strategy. CONREPNET Project Report. IHS BRE Press. Watford, UK. 9

89 REQUISITE HOLISM OF THE FEASIBILITY OF DELIVERING ZERO CARBON BUILDINGS Wei Pan 1 and Yan Ning Department of Civil Engineering, The University of Hong Kong, Hong Kong 1 Corresponding Author wpan@hku.hk, Tel: (852)

90 REQUISITE HOLISM OF THE FEASIBILITY OF DELIVERING ZERO CARBON BUILDINGS ABSTRACT Zero Carbon Building (ZCB) has been regarded as an innovative model of sustainable development in the built environment, being adopted by many governments as an important climate change strategy. However, there exist perceptions that a ZCB may not be achievable and may prove to be economically or socially unsustainable. The aim of this paper is to examine the feasibility of delivering ZCBs in the urban environment in a systems manner. The examination is carried out in a framework of five aspects, namely, technical feasibility, commercial viability, supply chain competency, market preference, and statutory and regulatory acceptance. The examination draws on previous research on ZCB as well as case study with a number of pioneering ZCB projects worldwide. The results suggest that ZCB designs can be technically feasible with the rational design strategy embracing passive design and energy efficiency coupled with the use of on- and off-site renewable technologies. The commercial viability of ZCB was traded off with achievable non-cost values, e.g. raised reputation. A requisite holism is proposed to examining the feasibility of ZCB, which explicitly identifies the relevant essential elements and parameters of ZCB and sets the boundaries including building lifecycle, stakeholder, geography, density, climate, sector and institution. This requisite holistic approach should help to achieve ZCBs in the urban environment in an integrative and effective manner. Keywords: Zero carbon building; Systems approach; Urban sustainability; Requisite holism. 1. INTRODUCTION Zero Carbon Building (ZCB) has been regarded as an innovative model of sustainable development in the built environment. The Construction Industry Council (CIC 2012) has constructed the first ZCB in HK in 2012, as a signature project to showcase stateof-the-art green design and technologies to the construction industry and raise community awareness of sustainable living. These contextual factors together suggest an unprecedented opportunity for ZCB, as a cutting-edge model of green building, to help drive the transition of the built environment towards low carbon and sustainable development. The aim of this paper is to examine the feasibility of delivering ZCBs in the urban environment in a systems manner. The examination is carried out through the lens of five aspects, namely, technical feasibility, commercial viability, supply chain competency, market preference, and statutory and regulatory acceptance. 2. PARADIGMS OF FEASIBILITY STUDIES: SINGLE ASPECT TOWARDS REQUISITE HOLISM A feasibility study is an analytical tool used during a business development process to show how a business would operate under a set of assumptions (Brockhouse and Wadsworth, 2010). It is found that the aspects examined in feasibility studies are specifically customized to their subjects examined. For example, the examination of the feasibility of inter-organizational systems by Gogan et al. (2011) requires an additional examination of the relational aspect, besides the technical, economic and operational aspects. In the feasibility study of construction projects, environmental, economic and technical aspects are commonly examined (e.g., Shen et al., 2010, Ng et al., 2010). Shen et al. 2

91 (2010) identified eighteen economical, nine social and eight environmental performance criteria from 87 feasibility study reports carried out in China. They found that that economic performance is still the biggest concern in the current practice of project feasibility study, compared to the social and environmental performance. Therefore, Shen et al. (2010) suggested the need for shifting the traditional approach of project feasibility study to a new approach that embraces the principles of sustainable development. Shen et al. s (2010) study, like many others, considered the empirical evidences as their grounds on which the aspects of feasibility studies are examined. However, such method often makes theoretical grounds of the aspects examined in feasibility study implicit, which may render some critical aspects being overlooked. It is also found that the feasibility in a single aspect, e.g. the technical, political, environmental and profitability aspect, cannot guarantee the feasibility of the whole business (see Zoulias and Lymberopoulos, 2007). Zoulias and Lymberopoulos (2007), for example, argued that that the replacement of fossil fuel based gensets with hydrogen technologies is technically feasible, but still not economically viable, unless significant reductions in the cost of hydrogen technologies are made in the future. Similarly, Chang et al. (2013) suggested that photovoltaic technology is economically feasible, but its market value may be significantly distorted by the policy factors. An implication of these findings is that the use of feasibility study should adopt a holistic approach. However, the goal of holistic study is not to look at everything ; instead it is to make a decision about what is relevant to the study and what is not and to know and understand why those choices were made (Mulej, 2007: 348). This decision can be grounded on dialectical system theory, through which the law of requisite holism can be met (Mulej, 2007). A dialectical system consists of a system (ordered set, network) of interdependent crucial viewpoints of dealing with the topic at stake (Mulej, 2007). Hitherto, there is still a lack of systematic examination of the aspects of feasibility studies. Adapted from Pan and Maxey s (2013) PESTEL framework (Political, Economic, Sociocultural, Technological, Environmental and Legal) of analyzing the challenges and opportunities of low or zero carbon building and grounded on the theory of requisite holism (Mulej, 2007), this paper aims to examine the feasibility of delivering ZCBs within a framework of five aspects, namely, technical feasibility, commercial viability, supply chain competency, market preference, and statutory and regulatory acceptance. The examination draws on previous research on ZCB as well as case study with a number of pioneering ZCB projects worldwide. Purposive sampling was used to select the cases, following the criterion that the targets should be the pioneering ZCB projects in the world and help achieve the research aim. 3. FEASIBILITY OF ZCB IN URBAN ENVIRONMENT 3.1 TECHNICAL FEASIBILITY Technical feasibility, albeit still being one of the main concerns for ZCB (Osmani and O Reilly, 2009), has been remarkably enhanced, manifested by the emerging ZCBs around the world. Li et al. (2013) classified the technologies into two groups: renewable 3

92 energy technologies; and energy efficient measures. Li et al. s (2013) literature review found that most of the renewable energy technologies are rather well established. The main technologies considered as renewable are photovoltaic, solar hot water, ground cooling, ground source heat pumps, wind turbines and biomass (Day et al., 2009). An investigation of a single-family home in Newfoundland indicated that zero energy homes based on wind conversion systems are feasible (Iqbal, 2004). The introduction of wind energy based zero energy homes, as explained by Iqbal (2004), is because the population of Newfoundland is scattered thereby providing many opportunities. Unlike this case using wind conversion system, an experiment of NZE village house in Hong Kong by Fong and Lee (2012) showed that a proposed design of NZE village house can be realized technically for the nominal efficiencies of the PV panels and BIPV above 13%, together with good behaviors. However, the wide diffusion of PV and wind turbines generation in HK may cause power instability and compromise the quality of existing power grid structure (Li et al., 2013). No tangible electricity feed-in tariff scheme for the surplus electricity from the renewable energy facilities in HK is another obstacle (Fong and Lee, 2012). This suggests that the link the existing infrastructure to newly adopted renewable technologies is an indispensable step to make the technology adoption a success. Compared to in the suburb environment, delivering ZCBs in urban areas is more challenging (Hui, 2001). However, the density urban environment is not simply deemed to render challenges for delivering ZCBs only; it also brings about positive impacts, e.g. the higher efficiency of district cooling and heating system, decreased heat loss from the buildings, reduced solar exposure of buildings (Hui, 2001). 3.2 COMMERCIAL VIABILITY Commercial viability is still a serious concern regarding the feasibility of delivering ZCBs (e.g., Fleming, 2009, Joao, 2012). Joao s (2012) study, albeit making evident of the influence of photovoltaic technology on energy saving, found that due to the high price of the photovoltaic, the commercial viability is still low. This is in line with Osmani and O Reilly s (2009) survey that additional costs associated with building ZCBs as being a major financial impediment. Long payback periods of the micro-generation technologies, like photovoltatics, are a particular concern to their adopters (Davies and Osmani, 2011). Fleming (2009) found that creating an affordable ZCB in a hot humid climate like Gainesville, Florida is both technically and commercially feasible with dedication to schematic design, a whole building systems approach, and implementation of costeffective components. In this analysis based on a 30-year period, government and local utility rebates, incentives, and feed-in tariff program were included to help offset the increased initial investment (Fleming, 2009). However, the situation faced in Hong Kong is different as there is no subsidy or incentive scheme for the installation of the solar panels and other renewable energy facilities (Fong and Lee, 2012). Thus, it is not straightforward to evaluate the economic feasibility of the ZCB. To increase the feasibility of achieving ZCBs in the UK, Osmani and O Reilly (2009) recommended that the overall cost of the Code for Sustainable Homes-compliant housing projects could be reduced by a change in government s definition of zero carbon homes, which facilitates the use of Energy Service Companies, and use of offsite construction. Similar situation is also encountered in Hong Kong. 3.3 SUPPLY CHAIN COMPETENCEY Osmani and O Reilly s (2009) survey of UK s house builder found that the challenges, 4

93 like legislative, cultural, financial and technical barriers facing house builders, are not insurmountable provided that a swift, all-embracing and above all realistic strategy is adopted and implemented across the supply chain. Existing ZCB practices suggest the need for a systems integration of the design strategies including passive design and energy efficiency with on and off-site renewable energy technologies. The use of such strategies indicates a strong need to understand the supply chain of delivering ZCB, comprising the supply, demand, regulation and institution sides. However, there is still little research in this regard. 3.4 MARKET PREFERENCE Market preference for ZCBs is deemed to be a great motivation to deliver ZCBs. Davies and Osmani (2011) found that contribution towards sustainable communities for all stakeholders is the most important driver for low carbon refurbishment in England. However, Osmani and O Reilly s (2009) survey of UK s house builders found that the concern of customer demand for ZCB is still a significant barrier. The increasing market demand is expected to create a positive impact on the ZCB agenda. 3.5 STATUTORY AND REGULATORY ACCEPTANCE Political and legislation drivers have vital roles to play in fostering changes within the building industry (Pan and Maxey, 2013). This driving force may be manifested into three dimensions: the integration of energy efficiency and renewable technologies; the translation of investments in energy savings into economic value; and the commitment towards nearly zero-energy target (Annunziata et al., 2013). Many governments have adopted the ZCB model as an important strategy for addressing climate change, achieving a low carbon economy and uplifting quality of people s life (Wilford and Ramos 2009; Pan and Garmston 2012). For example, the UK government has set ambitious targets to achieve zero carbon for new homes from 2016 (DCLG 2006:15) and for non-domestic new buildings from 2019 (HM Treasury 2008:7). In Europe, there are legal requirements of the Energy Performance in Buildings Directive (EPBD) recast for all new buildings to be nearly zero-energy by 2020 (European Union 2010:21). Similarly, in the US the Energy Independence and Security Act of 2007 authorizes the Net-Zero Energy Commercial Building Initiative to support the goal of net zero energy for all new commercial buildings by 2030, and further specifies a zero-energy target for 50% of US commercial buildings by 2040 and net zero for all US commercial buildings by 2050 (Crawley et al. 2009). A survey of the 27 European Union Member States found that European countries adopted different approaches in the design of their national regulatory framework (Annunziata et al., 2013). This heterogeneity consists of four main factors: different authorities involved in energy regulations, traditional building regulations and enforcement models, different contextual characteristics, and maturity of the country in the implementation of energy efficiency measures (Annunziata et al., 2013). Therefore, Annunziata et al. (2013) suggested that these differences are important to take into account country s profile in order to improve the sharing of best-practices and energy efficiency governance, ultimately contributing to the feasibility of ZCB. 4. PIONEERING CASES OF ZCB AROUND THE WORLD Five cases of ZCB were examined through the lens of the proposed feasibility study framework. These five cases are located in various geographic areas consisting of US, Europe, Singapore, Australia and Hong Kong (Table 1). 5

94 Case 1 Melink (LEED EB Platinum) Sustainable Building 2013 Hong Kong Regional Conference Table 1: A SUMMARY OF FIVE PIONNERING ZCB CASES EXAMINED Projects and their Characteristics Technical solutions Referen performance ce renovation; through energy efficient building Minor, containing both design, added renewable 2011 manufacturing and energy technologies and office functions; optimized building control; 2,902 m 2 ; NZEB performance is located in Cincinnati, attainable. Ohio. 2 BOLIGt (The first demonstration project of a multistorey residential Net ZEB in Denmark) 3 Pixel Building (The first carbonneutral office building in Australia.) 4 CIC zero carbon building (The first zero carbon building in HK; BEAM Plus Platinum) 5 Zero energy BCA Academy (The first zero energy building in Singapore) located in a dense city of Danish; residential building; one part of 6-stories and a second part of 10 stories; 7000 m 2 ; assembled from 114 modules with an average area of 61.4 m 2 small scale commercial building; located in suburb of Carlton, Melbourne; investment of $6M; four floors 1,000 m 2 3 storeys including basement 14,700m 2 invested by CIC and the development Bureau, located in HK renovation government office and academic facilities investment of S$11 million by BCA, Singapore 4,500 m 2 located in Singapore first reduce the energy use to a minimum, and then apply renewable technologies to offset the remaining energy consumption; the PV installation combined with PV/T and a solar heat pump is the the most energy efficient solution; material selection is critical, like using pixelcrete, secondhand access flooring, secondhand carpet tiles, recycled timber, low-voc paints, secondhand photovoltaic cells, and doubled glazing. passive design, green active systems, bio-fuel Tri-generation system, PV panels, low embodied carbon materials. pass design: harness nature s energy and minimize solar heat gain; active solutions: energy efficient building systems and equipment that provide for our comfort and function; operate at same level of service using less energy; active control: management and optimization and user discipline. Marszal and Heiselb erg, 2011 Zuo et al., 2013 To, 2013 BCA, 2009 All the five cases provided solid evidence that ZCBs can be technically achieved with dedication to rational design strategy embracing passive design and energy efficiency coupled with the use of on- and off-site renewable technologies, even in the dense urban environment (see Cases 2, 4, 5). However, it is worth noting that all cases are low-rising or multiple-storey buildings, it is still largely unknown whether or not ZCB in high-rise buildings in high density areas, like Hong Kong, is technically feasible. When considering the commercial viability, Marszal and Heiselberg (2011) suggested that it is crucial to first reduce the energy use to a minimum and afterwards apply renewable technologies to offset the remaining energy consumption. In the case of multi-storey ZCBs, they also recommended that prefabricated modular building 6

95 construction could have great potential for reducing the cost of construction with higher thermal properties (Marszal and Heiselberg, 2011). Supply chain competency is important to deliver ZCBs. In Case 3, Zuo et al. (2013) found that reuse and recycling of materials helps to achieve the carbon neutrality goal. An implication is that with the aim to deliver ZCB, material suppliers should forge their competency to supply greener products and materials. Besides, they noticed that the participants in Case 3 all expected to get subcontractors involved in achieving the goal carbon neutrality. Since Cases 4 and 5 were both publicly funded, with the aim to showcase the state-ofthe-art eco-building design and technologies and to increase the public awareness of low carbon life, there are no concerns of market preference. However, these initiatives indicate governments strong commitment to reduce carbon emission in the construction sector. The case study of five ZCB projects suggests that feasibility studies of ZCB should be carried out in a systems manner and that the proposed feasibility study framework is valid and useful to guide feasibility studies of ZCB projects. 5. CONCLUSIONS This paper has attempted to contribute to knowledge of the feasibility of delivering ZCBs by proposing a systems theory based feasibility study framework. This framework comprises five aspects: technical feasibility, commercial viability, supply chain competency, market preference, and statutory and regulatory acceptance. Practitioners could therefore examine their proposed ZCB using such framework and any feasibility indices to be developed. The examination of the feasibility of delivering ZCBs through desk study of literature and the existing real-case ZCBs should increase practitioners understanding of the challenges and opportunities of building ZCBs in the urban environment. The results suggest that ZCB designs can be technically feasible with the rational design strategy embracing passive design and energy efficiency coupled with the use of on- and off-site renewable technologies. The commercial viability of ZCB, although raising a big concern if adapting the ZCB solutions in the pioneering projects to industry-wide practices, would be traded off with achievable noncost values, e.g. raised reputation. Statutory and regulatory acceptance plays an important role in driving actors to put efforts on delivering ZCBs, which however largely depends on the government s commitment to the ZCB agenda. 6. REFERENCES Annunziata, E., Frey, M. and Rizzi, F., Towards nearly zero-energy buildings: The state-of-art of national regulations in Europe. Energy. Brockhouse, J.W. and Wadsworth, J.J., Vital steps: a cooperative feasiblity study guide. U.S. Department of Agriculture Rural Business-Cooperative Service Service Report 58 [online]. Available from: (Accessed 4 th April 2013). BCA, Singapore s first zero energy building. The Magazine of the Institution of Engineers, Singapore. Chang, H. J., Kim, I. S., Kim, D. W. and Yang, T., Business potential of sustainable energy in Korea: Hybrid method of various feasibility studies from path dependence and path evolution perspective. Renewable Energy, 50, Crawley, D., Pless, S. and Torcellini, P., Getting to net zero. ASHRAE Journal, 51(9),

96 Davies, P. and Osmani, M Low carbon housing refurbishment challenges and incentives: Architects perspectives. Building and Environment, 46(8), DCLG, Building a Greener Future: Towards Zero Carbon Development: Consultation, Department for Communities and Local Government (DCLG), London. Day, A. R., Ogumka, P., Jones, P. G. and Dunsdon, A., The use of the planning system to encourage low carbon energy technologies in buildings. Renewable Energy, 34(9), EU, Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast). Official Journal of the European Union. Fleming, B. A., Feasibility Analysis for the Development of Affordable Net-zero Energy Housing in Gainesville, Florida. University of Florida. Fong, K. and Lee, C., Towards net zero energy design for low-rise residential buildings in subtropical Hong Kong. Applied Energy, 93, Gogan, J. L., Baxter, R. J., Garfield, M. J. and Usoff, C., Pilot-Testing Inter- Organizational Systems to Reveal Relational Feasibility Issues. Emj-Engineering Management Journal, 23(3), HM Treasury, Budget 2008 stability and opportunity: building a strong, sustainable future, The Stationery Office, London. Hui, S., Low energy building design in high density urban cities. Renewable Energy, 24(3), Iqbal, M. T., A feasibility study of a zero energy home in Newfoundland. Renewable Energy, 29(2), Li, D. H., Yang, L., and Lam, J. C., Zero energy buildings and sustainable development implications-a review. Energy. Marszal, A. J. and Heiselberg, P., Life cycle cost analysis of a multi-storey residential Net Zero Energy Building in Denmark. Energy, 36(9), Minor J, H. K., Renewable energy design and performance of LEED EB platinum building for zero energy programme. ASHRAE Trans. Mulej, M., Systems theory: a worldview and/or a methodology aimed at requisite holism/realism of humans' thinking, decisions and action. Systems Research and Behavioral Science, 24(3), Ng, S. T., Wong, Y. M. W. and Wong, J. M. W., A structural equation model of feasibility evaluation and project success for Public-Private Partnerships in Hong Kong. IEEE Transactions on Engineering Management, 57(2), Osmani, M. and O'Reilly, A., Feasibility of zero carbon homes in England by 2016: A house builder's perspective. Building and environment, 44(9), Pan, W. and Garmston, H., Compliance with Building Energy Regulations for New-Build Dwellings. Energy, 48(1), Pan, W. and Maxey, L Challenges and opportunities of low or zero carbon building: prospects of business models. Paper presented at CIB World Building Congress. Brisbane: Australia, 5-9 May Shen, L.Y., Tam, V. W. Y., Tam, L. and Ji, Y.b., Project feasibility study: the key to successful implementation of sustainable and socially responsible construction management practice. Journal of Cleaner Production, 18(3), To, C., Experience Gained from the First Zero Carbon Building in Hong Kong. Presentation at CICID 10th Anniversary Conference, Hong Kong, 31 May. Zoulias, E. I. and Lymberopoulos, N., Techno-economic analysis of the integration of hydrogen energy technologies in renewable energy-based stand-alone power systems. Renewable Energy, 32(4), Zuo, J., Read, B., Pullen, S.and Shi, Q., Carbon-neutral commercial building development. Journal of Management in Engineering, 29(1),

97 HOW TO CREATE SUSTAINABLE COMMUNITIES IN HONG KONG? INHERENT PROBLEMS OF RECENT URBAN LAYOUTS FOR MICROECONOMIC OPPORTUNITIES AND QUALITY OF LIVING Hendrik Tieben 1 Associate Professor, School of Architecture, The Chinese University of Hong Kong (CUHK) Essy Baniassad Research Professor, School of Architecture, CUHK Sujata Govada Adjunct Associate Professor, School of Architecture, CUHK Helen Grace Visiting Professor, Department of English, National Central University Jhongli, Taiwan 1 Corresponding Author Hendrik Tieben: hktieben@cuhk.edu.hk. Tel: (852)

98 HOW TO CREATE SUSTAINABLE COMMUNITIES IN HONG KONG? INHERENT PROBLEMS OF RECENT URBAN LAYOUTS FOR MICROECONOMIC OPPORTUNITIES AND QUALITY OF LIVING ABSTRACT As the Hong Kong SAR Government embarks on new large-scale development projects in the North-East New Territories and Hung Shui Kiu, the following paper explores the qualities and inherent obstacles in Hong Kong s urban design and planning approach. The paper is based on the authors research on districts in Hong Kong, namely Sai Ying Pun and Tin Shui Wai. It proposes to learn from the merits of Hong Kong s early districts: their integrated street networks, small blocks, mixed-use typology and active street frontages enhancing connectivity and generating a multitude of social and economic activities. These advantages contrast with the conditions of Hong Kong s recent new towns, which stifle individual initiatives, restrict microeconomic opportunities, and limit the life experiences of their residents, usually the poorest part of the city s population. As the paper argues, the understanding of the relationship between urban form and microeconomic opportunities is essential in creating a better quality of living and nurturing sustainable communities in Hong Kong. Keywords: New town design, microeconomic opportunities, quality of living. INTRODUCTION In his 2013 policy address, Hong Kong SAR s Chief Executive Leung Chun-ying promised to increase the supply of subsidized housing. As a long-term land development strategy he confirmed plans for the New Development Areas in North- East New Territories and the Hung Shui Kiu district adjacent to Tin Shui Wai. Both plans were already mentioned in the Hong Kong 2030 Study: Planning Vision and Strategy (2007). This paper makes use of these plans to reflect upon the merits and challenges of Hong Kong s urban design and planning approaches, highlighting aspects that have not been explored enough and presenting inherent obstacles for the building of sustainable communities. Over the past years, there have been various initiatives to link questions of urban form, socio-economic issues and climate change in considering the interrelationship between different scales from individual buildings, to neighbourhoods and to metropolitan regions. Patrick M. Condon presents a notable holistic approach in his recent book: Seven Rules for Sustainable Communities: Design Strategies for the Post-Carbon World (Condon, 2010). He proposes the following points should be considered in urban design and planning: 1) Restore the street car city; 2) Design interconnected street systems; 3) Locate commercial services, frequent transits, and schools within a five-minute walk; 4) Locate good jobs close to affordable homes; 5) Provide a diversity of housing types; 6) Create a linked system of natural parks; and 7) Invest in lighter, greener, cheaper, and smarter infrastructure. These points offer a clear idea on how environmental, economic and social factors are related to fundamental decisions in urban design and have been adopted as a basis for the present paper. Although Condon s seven rules are to be understood as interrelated 2

99 and all of them should deserve our attention, this paper focuses on points 2), 3) and 5) in particular, for they are the least considered aspects in the context of Hong Kong. Hong Kong, due to its high density, efficient public transport system and protected country parks, has favourable conditions to become a carbon efficient and sustainable city. However, its most recently developed new towns have failed in their social integration, economic opportunities and quality of living. And the city is observing its dropping quality of living rankings in comparison to other cities in the region, particularly Singapore 1. While such quality of living rankings could play a positive role in pushing governments and professionals to reflect on the effectiveness of their current development projects and therefore contribute to improving the living conditions of citizens, based on their particular focuses they might not capture factors of key concern for local communities, especially those living in low-income areas. Hong Kong is often portrayed as a place where everything seems to be measured in monetary terms. The Wall Street Journal and Heritage Foundation have ranked Hong Kong for the 17 th time as the world s freest economy 2 ; and the World Bank and the International Finance Corporation celebrated the city as the second best place for doing business 3. Thus it might come as a surprise to some that this paper investigates the lack of (micro)economic opportunities in parts of Hong Kong and its deep, adverse effects on the quality of living of a substantial number of residents living in these low-income areas. Tin Shui Wai and Tung Chung, Hong Kong s most recently developed new towns, are areas with particularly high concentration of low-income residents. The first new town projects in Tin Shui Wai date back to 1982, but social problems seem to be found mainly in projects completed since The Tin Shui Wai new town stretches over an area of 4.3 km2 and has a considerable population size of 292,000 residents (Civil Engineering and Development Department, 2012). Thus it has 100,000 more residents than for instance the flourishing Swiss city Basel 4 ; and together with its two adjacent areas of Yuen Long new town (211,000 residents) and the new development of Hung Shui Kiu envisioned to accommodate 160,000 people, we are talking about an urban area with more residents than the city of Vancouver. While scrutinizing the differences between these new towns and Hong Kong s earlier districts, such as Sai Ying Pun, the paper also challenges popular planning ideas such as transport oriented developments and urban nodes if they are considered as formulae to guarantee the development of green and sustainable cities. Even in much celebrated cities like Vancouver, studies are emerging that the design of urban nodes around costly mass-transit infrastructure like the Skytrain could have limitations in activating larger urban areas, and performing less successfully than earlier developed areas based on integrated street networks and street cars, despite 1 Most of the Quality of Life indices are produced by international management and employee placement agencies and are concerned with conditions for expatriate employees and managers and have no interest in the quality of life for those who live in the placement locations. For data that specifically measures the quality of life in Hong Kong, see: The Centre for Quality of Life, Chinese University of Hong Kong: 2 See: 3 See: 4 The Basel comparison is perhaps apposite in that Hong Kong has sometimes been called the Switzerland of Asia (Lo, 2005) on the one hand, and on the other, Basel in the form of the Basel Art Fair has recently moved its brand to Hong Kong, taking over control of the Hong Kong International Art Fair. 3

100 their lower travel speed. These studies consider trip duration, walkability, closeness to businesses and schools, cost of infrastructure investments, energy consumption and carbon emission, flexibility in land uses and social benefits through the synergetic effects of a highly interlinked network (Condon, 2010). Following these studies, it is not surprising to find that many cities that usually top the quality of living and sustainability rankings, including Portland, San Francisco, Vancouver, and Zurich, depend to a large extent on integrated street networks serviced by street cars. In fact, Hong Kong s older districts, which were developed in the same period as those western cities in the late 19 th century, share very similar grid layouts, small urban blocks and public transport systems (of trams, buses and later an underground mass transit system). However, like many North American cities, following the introduction of private automobile, modern planning ideas and standard vehicular road design, the earlier street grid patterns have disappeared almost entirely from the urban planning repertoire. In Hong Kong, with the exception of two entries for the West Kowloon Cultural District master layout by Foster & Partners and by Rem Koolhaas 5, it is revealing that the idea of grid patterns returns at a moment when government agencies and urban planners seek to boost creative districts. However, the highly connected grid pattern is absent in the layout of new towns in Hong Kong, which are planned purely for housing. This paper takes as its general approach Edward Soja s observation of a spatial turn (Soya, 1996), which allows us to understand that not only do economic and social conditions shape urban environments, but also the other way round, that spatial configurations can deeply affect economic and social conditions of a place. To investigate the differences between Hong Kong s older areas (designed based on integrated street grids and mixed typologies) and recent new towns, we have selected the districts of Sai Ying Pun and Tin Shui Wai for comparison. The comparison is enlightening in various ways. Tin Shui Wai has been a widely discussed new town because of its social problems, it is therefore important to understand the potential impact of planning decisions on its social environment, pitting against the merits of Hong Kong s older districts like Sai Ying Pun, one of the city s first urban expansions in the s. While the living environment in Sai Ying Pun can t be considered as perfect especially in regards to its air quality (Ng, 2010), its spatial configuration allowed its mostly low-income residents a range of life choices, and opportunities for social integration and mobility. The following section will present how these merits were not adopted in the layout of Tin Shui Wai and those choices and opportunities are thus largely missing in the area (Chui, 2008). In addition, these qualities in Sai Ying Pun and other older districts of Hong Kong are disappearing due to development pressures brought about by recent urban renewal and infrastructure developments. 5 See: 4

101 Figure 1: Study Areas: Tin Shui Wai New Town (Area A south & B north) & Sai Ying Pun District ALLOCATION OF COMMERCIAL SPACES LIMITATION OF THE TOD 6 +NODE MODEL Similar to North American suburbs, Hong Kong s new towns are developed according to a zoning system. Commercial as well as leisure facilities are interpreted as destinations or nodes (in Hong Kong, these are mostly shopping centres and markets). In each super block of Tin Shui Wai, there is always a commercial centre. Following the TOD standard, each of those centres can be reached within a 400m-walk from the surrounding housing blocks and the light rail stops. This idea is generally positive, as it guarantees the supply of daily goods in walking distance from home. Similar ideas were also applied in Hong Kong s private housing developments, including the LOHAS Park, a so-called green town recently developed by the MTR Corporation, on a single podium covering a 33ha site. In Tin Shui Wai, the 400m passages between each node are initially envisioned as pedestrian corridors along continuous green spaces. However, they are often executed with hard and sealed surfaces for fire engine and ambulance access, or simply to save money from the higher maintenance cost for green spaces. These projects follow planning standards with little or no emphasis on urban design and place making and mainly aim to ensure fast vehicular traffic, safe pedestrian circulation, an increased amount of open space for better air ventilation, at the same time maximizing housing density. However, if all these goals are followed without taking into consideration an integrated street network, the quality of street spaces, active street frontages and a mixed-use typologies, the bustling social activities in older parts of Hong Kong become impossible to realize in the city s recent new towns. 6 Transit-oriented development 5

102 Figure 2: Tin Shui Wai Main Arterial (Tin Shui Road), 2013 Instead of letting the main street become the backbone of commercial and social life, buildings in Tin Shui Wai turn their back to the street. Integrated street networks with narrow streets and small blocks facilitate and multiply choices and experiences of pedestrian movement, while large super blocks, as they are realized here in the district, are connected to a system of wide distributor roads that substantially discourage walking. In Tin Shui Wai, pedestrians walk 400 meters along largely enclosed buildings on the main street, realize then that they can t cross to the opposite side of the distributor road, as pedestrian crossings are rare, and are forced to take long detours over footbridges. After taking such a walk along such an inconvenient and inactive main arterial once, there is no motivation to come back again. Similar uninviting street spaces can easily be found in other areas recently built in Hong Kong (including those with luxury residential complexes). Affluent people might prefer these areas as they are located outside the busy and crowded city centre and offer more living space, amenities and better air quality. For them the lack of street activities is less a problem, as they can send their domestic helpers to do the daily shopping or call delivery services, and can take taxis or private cars to reach more attractive environments as they want (thus however increasing the city s carbon footprint). Also they are more likely working in sectors that do not depend on microeconomic opportunities. However, low-income residents are left with no other alternatives than to stay and accept their surroundings. Many of Tin Shui Wai s residents earn if employed not more than Hong Kong s minimum wage of 30HKD/hour; thus an MTR ticket to areas with more job opportunities takes a substantial part of their low salaries. As Tin Shui Wai lacks major employment centres and places for social interaction, we need to ask why the most appropriate locations for businesses and social activities, where people usually would walk and interact remain deserted. This becomes especially evident at the street corners of Tin Shui Wai s main arterial. In a town of such high density, corner locations on main streets would be where businesses thrive. 6

103 Figure 3: Tin Shui Wai North (Area B), Pedestrian Linkages to Neighbourhood,

104 Figure 4: Tin Shui Wai Main Arterial (Tin Shui Road), 2013 However, due to the master plan design, we find large car-park buildings of enclosed shopping centres at these locations while pedestrians are re-routed away from corners to footbridges. In our observation in Sai Ying Pun, street corners are popular places where people would gather and talk; similar observations were made by William H. Whyte in New York and Tokyo (Whyte, 1980, 2000). However, even Sai Ying Pun s Centre Street has lost much of its previous social activities and is constrained by railings for road safety, limiting freedom of pedestrian movement and encouraging drivers even to speed up. Condon described the social life that tends to develop around arterial structures in integrated street network serviced by street cars (similar to the light rail system in Tin Shui Wai): Once at the arterial, [pedestrians] turn either ninety degrees right or ninety degrees left to take advantage of services on the two or three blocks in either direction. Thus, their sense of the place is determined by their walk to the arterial and their eventual familiarity with the blocks immediately in either direction. [ ] Vibrant streetcar streets are experientially very rich, with buses or streetcars arriving and departing every few minutes, familiar shopkeepers sweeping sidewalks, denizens of ethnic social clubs arguing on sidewalks, school kids walking to the local library branch, and teens showing off. They offer a unique dialectic between the freedom of action allowed by the apparently infinite length of the corridor and the proxemic familiarity that characterizes the best of village environments. (Condon 2010, 70) 8

105 Little of this happens along Tin Shui Wai s arterial for its lack of consistent planning and programing. Alternatives are possible, as the case of the nearby Yuen Long district shows. The current layout of Yuen Long emerged from an earlier market place and therefore still followed a smaller integrated grid. Its main arterial is narrower than the one of Tin Sui Wai, and in contrast is lined by mixed-use buildings with street-level shops. The light rail services both towns, yet its tracks also separate their main streets. A modern street car system like Portland s TriMet might be able to solve this problem. Nevertheless, Yuen Long s Castle Peak Road, in contrast to Tin Shui Wai s inconvenient Tin Shui Road, is full of life, reaching almost the same intensity as that of Nathan Road, Kowloon s famous main arterial. Tin Shui Wai s arterial and other recent main arterials in Hong Kong are surprisingly wide. Cities in the USA, with much higher vehicle ownership (overall 797 cars per 1000 people in 2010, according to data.worldbank.org), are diminishing space for vehicular traffic on their downtown streets, and allocate the gained space to pedestrians and bikers, for instance at the recently redesigned Broadway in New York. In contrast, Hong Kong, with one of the lowest vehicular ownership rates in the developed world (77 cars per 1000 people in 2010, according to data.worldbank.org), built much wider roads in new towns like Tin Shui Wai. This happened despite the fact that Tin Shui Wai has a light rail, bus and MTR services and most of its population is too poor to afford private cars. The large road size is linked to the system of super blocks, in which traffic accumulates on distributor roads, rather than being diffused into an integrated street network with smaller and better walkable streets. In terms of safety, building large distributor roads might not be the best solution. Peter Swift s research in North-America registered that the number of pedestrians killed in accidents on wide suburban residential roads was four times higher than that on narrower traditional urban streets, as wide roads invite drivers to drive faster and leave them less time to react to unexpected crossing pedestrians. Moreover, accidents with pedestrians at a driving speed of 35mph are much more likely to be fatal (Swift, 1998, Condon, 2010). In Tin Shui Wai, the danger caused by fast vehicular traffic is addressed by re-routing the pedestrian flow away from the road to footbridges, thus significantly reducing the connectivity of the pedestrian network and the walking experience. These detours are especially inconvenient and uncomfortable for the infirm, the elderly and for mothers with children. Similar problems are also occurring in Sai Ying Pun now. Along its narrow residential streets, mini buses and trucks are allowed to drive at 30mph. As this creates fatal accident risks for pedestrians walking along the extremely narrow sidewalks, railings are put up at most street corners to improve road safety, destroying the otherwise excellent pedestrian connectivity and encouraging even higher vehicular speed. Other cities like New York, Portland, and Vancouver employ the exact opposite strategy of drastically reducing vehicular speed and removing railing obstacles to enhance road safety and pedestrian movement at the same time. 9

106 Figure 5: Comparison of Tin Shui Wai (left) & Sai Ying Pun (right) according to: Road Patterns, Configurations, Route Structures, Complexity & Connectivity 10

107 Figure 6: Activities at Street Corner, Sai Yin Pun, 2012 MICRO-ECONOMIC OPPORTUNITIES IN SAI YING PUN AND TIN SHUI WAI After discussing the design of main arterials, it is time for a deeper study of the particular conditions facilitated by the integrated street network, mixed typologies and active street frontages in Sai Ying Pun, and a comparison to Tin Shui Wai. Sai Ying Pun was one of the first expansions of the City of Victoria a decade after the establishment of the British colony of Hong Kong (Tieben, Woo, Yuet, 2009). The rectangular grid layout was an attempt to provide healthier living conditions comparing with the earlier developed Tai Ping Shan area. The northern part of the district was quickly built up due to its vicinity to the go-downs at the harbour and the high demand for accommodations due to the growing number of refugees from the Taiping rebellion ( ). In 2012, we conducted a survey of all ground-level businesses and workshops in Sai Ying Pun, which allowed us to study the changes of the district after the opening of the new MTR West Island Line in 2014, and the almost completed hillside escalator on Centre Street. We organized the district layout in 25 blocks adjusted in shape to the irregular and steep terrain. The largest block, located between Queen s Road West and Des Voeux Road West, measures 141x96m. This is already relatively small in comparison to block sizes in other cities (pedestrian friendly cities Vancouver and Seattle have blocks of 200x100m on average, while Barcelona s example blocks are 113x113m). In addition, Sai Ying Pun s blocks are further subdivided by a system of alleys, lanes and terraces, creating high permeability and many choices for pedestrians to explore the district. The spatial quality of this system suffered over the years, due to a general 11

108 Figure 7: Ground Level Activities at Residential Tower, Tin Shui Wai North, 2012 neglect and building interventions that did not regard these streets, alleys and lanes as public spaces in this high-density district. Each block, depending on its size, has a different number of stores along its perimeters. Smaller blocks of 141x35m (for example between Queen s Road West and First Street) have around public/private interfaces that are usable for stores (Tieben, 2013). All 25 blocks together provide spaces for 1,240 shops and workshops, on the street level alone. If we assume that 2-3 people work in each shop, the district already generates 2,480-3,720 jobs. In addition, there are 121 stalls in the two indoor markets in the district 7 ; and there are many more agencies, associations, tutoring classes, medical and massage services on the upper storeys of buildings. The exact number of commercial activities is difficult to trace, as some of them operate in grey zones inside residential units. For business owners, this requires lower investments and therefore allows careful in setting up small businesses. Towards the two main arterials on Queen s Road West and Des Voeux Road West, there are also office towers with larger firms providin more substantial numbers of employment. At the same time, Sai Ying Pun has retained its role as a residential district with a population of 35,960, 50% of whom work in the same district according to hk.centamap.com. In addition to proper schools, the district also offers many supporting educational, social and community facilities (many of them located on the upper floors of buildings), catering especially for children and elderly people. With its close spatial integration, flexible typology, and large number of shops and workshops, the district attracted and accommodated waves of migrants from Mainland China - many of them with limited 7 See 12

109 means - and helped in integrating them into the Hong Kong society. Most jobs in Sai Ying Pun were not created based on a predefined plan of the government, by foreign 13

110 Figure 8: Comparison Ground Level Interfaces: Above: Tin Shui Wai North (Area B) / Below: Sai Ying Pun (same scale) Figure 9: Survey of Small Businesses and Workshops at Ground Level Tin Shui Wai North (Area A & B) and Sai Ying Pun (same scale) direct investments, or by global and local corporations. Instead the small businesses grew based on the initiatives, creativity and persistence of people with little means. When the district was first surveyed and laid out, its transformation into its current form, with high-risers of storeys and businesses selling products and providing services, could not have been imagined. These fundamental transformations were made possible by a simple but smart initial layout, offering maximal changeability of different social components while ensuring multiple interconnections among them to achieve a sense of community. In Tin Shui Wai, we selected for the study two areas with similar sizes of population to Sai Ying Pun (35,960 people): Area A, in the south of the district adjacent to the MTR, with 33,539 residents; and Area B, in the north of the district with 35,855 residents. 8 Average monthly income per person in Sai Ying Pun is 12,042 HKD while it is 8,328 HKD in Tin Shui Wai s Area A and 7772 HKD in Tin Shui Wai s Area B. The approximate proportion of Tin Shui Wai s residents who were born in Mainland China is 38% (Population By-Census, 2006). Both areas in Tin Shui Wai are organized as super blocks and surrounded by large distributor roads. Each super block contains one commercial centre with an integrated market. There are 142 businesses, private agencies and service providers in Area A s Tin Yiu Plaza, including stores on upper levels (18) and market stalls (75). The Tin Chak Shopping Centre of Area B has 189 businesses, including shops on upper levels (77) and market stalls (88). The numbers are similar in that they are fixed by design, which makes adaptability to changes almost impossible whether on the building or the urban scale. In residential towers in Tin Shui Wai, unlike the case in Sai Ying Pun, commercial activities are also not permitted (should such activities take place, residents would risk losing their subsidized home). 8 These population figures are taken from hk.centamap.com 14

111 As almost none of the businesses have access to street spaces, and they instead have to follow the strict management rules of shopping malls, it is impossible to open workshops (for example carpenters, car mechanics, bicycle repair and larger printing shops) in both areas (with a joint population of 69,394 people). William H. Whyte highlighted the essential role of food outlets in activating public spaces and facilitating social interaction; but in both areas, there are no places for Hong Kong s popular and affordable Dai Pai Dongs ( 大牌檔 - outdoor eateries) to operate, preventing low-income residents from enjoying al-fresco dining. All these design and management decisions strongly restrict what people can do, buy, and enjoy in this new town, and unnecessarily reduce job opportunities for the residents there. So while the amount of green open space is increased in Tin Shui Wai, life choices are problematically limited, especially when it is compared with the lively and crowded older districts. Tin Shui Wai s situation is particularly severe as chances are slim that investors from outside will invest in the district, while traveling to other areas with better job opportunities is costly and long. Would this situation be different if the district was built with an integrated street network, active arterials and flexible mixed-use typologies? The problem of poverty might not be easy to resolve; however, the sentiments of isolation, monotony and helplessness could more likely be changed. We can test this by looking at further examples: Sham Shui Po, while being another Hong Kong low-income district, is filled with bustling life, not substantially different from the busiest streets in Mong Kok, except that prices of goods are lower. In Sham Shui Po, Yau Ma Tei and Mong Kok, rows of street-level shops are combined with additional layers of hawkers, further increasing the activity level and micro-economic opportunities. Hawkers also existed in Sai Ying Pun until they were relocated to the indoor markets in the 1980s (Leeming, 1977). Sham Shui Po has made negative headlines due to its partitioned flats with people living in miserable conditions (Ng, 2012; Gayle, 2012; Cassey, 2013). While the greed of landlords is appalling, the fact that many people still choose to live there despite the inferior conditions might also indicate that in Sham Shui Po, it is easier for the urban poor to find a foothold, escape social isolation, and have choices and opportunities to survive. We have no information if there are people preferring Sham Shui Po s cage houses or coffin-homes in partitioned flats, to the relatively well-designed and significantly larger apartments in Tin Shui Wai. This might well be rare. However, based on our study of the different layouts and urban experiences among the districts, it is arguable, that the monotonous street spaces and the lack of opportunities in Tin Shui Wai are not only caused by the background and poverty of its residents (comparing with Sham Shui Po) and the distance to employment centres (comparing with Yuen Long) but are also deeply linked to its particular urban layout, building typology, and limited public/private space interfaces. ISOLATION AND HELPLESSNESS VS. CONNECTEDNESS AND EMPOWERMENT The common feeling expressed in the life stories collected by Eva Chan Sik-chi in her book Voices of Tinshuiwai Women (Chan, 2009) was a sense of helplessness and a lack of opportunities to shape destinies. Most of the women interviewees mentioned their uncomfortable feelings of being forced to accept social benefits instead of being able to work. 15

112 The comparison between Sai Ying Pun and Tin Shui Wai shows, that chances for Tin Shui Wai s residents to shape their destiny through their own initiatives are, in fact, substantially lower: the 1,361 places on ground level and in the markets in Sai Ying Pun versus Tin Shui Wai s 121 and 64 places in its Area A and Area B respectively. In addition, Sai Ying Pun offers various spaces on the upper floors of its older buildings, which are flexible enough to set up small businesses or agencies; nothing similar exists in Tin Shui Wai. These differences also have direct expression in street spaces: in Sai Ying Pun, we see on every step along the streets a multitude of commercial signs representing personal initiatives and investments into one s own business as well as the community, all this is missing in Tin Shui Wai s outdoor environment. As Sai Ying Pun s streets are full of shop signs that encourage its residents to become small entrepreneurs, there is almost no trace of evidence in Tin Shui Wai that personal business initiatives could ever work (an exception being the colourful displays of the kindergartens on the ground level of residential towers). As a response to the experience of helplessness, Professor Ernest Chui proposed to learn from these lessons of Hong Kong s new towns: With the concern for combating the widespread poverty in mind, a community economy can be developed in the new towns like Tin Shui Wai North, in which small businesses operate within the framework of social enterprises. Such social enterprises can help to create jobs, training, and the provision of services for people within a specific community. They are characterized by ethical values that carry a commitment to building people s skills in local communities. The profits generated from these small businesses are principally reinvested to achieve their social objectives [ ]. (Chui 2008, 67-68) While this proposal is a positive step ahead, our argument is that the layout and design of Tin Shui Wai s urban environment will hinder it, if planners fail to understand the impact of spatial design itself on determining what people can do in shaping their own destinies. With no alternatives left, residents in Tin Shui Wai North initiated their own informal hawker market along the river (a drainage channel according to the official planning language). Thus they followed the same strategy adopted by many other places to escape poverty and social isolation; the strategy is also practiced in Hong Kong s older districts for more than 170 years. The problem of the hawker market in Tin Shui Wai was not the shortage of vendors, customers, and goods, but, on the contrary, there were too many of them. In interviews, female hawkers regarded the opportunity to socialize as the second to the most important motivation for them to sell at the market. With an understanding of Tin Shui Wai North s urban form and its natural topography, they arranged their stalls along the most convenient circulation route next to the water, creating a synergy between the most attractive location and the directions where people tended to walk across. Thus the market quickly developed into the main community space of the district, and survived regular police attempts to stop the illegal commercial activity. After a tragic accident of an old hawker who drowned himself when trying to escape the police, the market was relocated in 2013 to a place near the Tin Sau light rail station. Newly designed hawker stalls were installed and the market has since been organized by the Tung Wah Hospital Group, Hong Kong s longest established NGO. While the market s legalization is commendable, the relocation, again, failed to create synergies. While the original market initiated by the residents was successful as it was linked to the daily movement patterns of the residents and the most beautiful scenery, it easily 16

113 attracted people to come and stay. In the new location selected by the government, the market struggles to survive as it hardly connects to the residents daily routes. Thus it requires a specific reason for residents to go there, instead of just passing by. And the market loses a quality that introduces liveliness into a monotonous and restricted district, as a sign of a collective community action, spatial ownership and empowerment. 9 If we would start to understand a new town like Tin Shui Wai, with a population of 292,000 people, not just as an assemblage of housing estates and new development areas but as a real city, it would be designed very differently: It would include a vibrant main street as the core collective community space and residents being treated as citizens, who would have a major say regarding, for instance, where the right place of their market should be. CONCLUSIONS With a lack of understanding and short-sighted profit seeking, public street spaces in Hong Kong s older districts (e.g. Sai Ying Pun) continue to degrade. New constructions eliminate their public-private interfaces and restrict opportunities for their micro economies. Road design focusing on high vehicular speed and pedestrian safety restricts movements, limits opportunities and choices. Thus the strengths of interconnected street network, proximity and interconnection are lost. Every day we experience the growing digital social networks which build on multiple links, immediacy and synergies. Similar qualities exist in Hong Kong s early developed districts with small blocks, narrow streets, a multitude of interfaces and mixed-used typologies. Jane Jacobs has defended these qualities already (Jacobs, 1992), while Christopher Alexander reminded us that a city is not a tree (Alexander, 1966), attacking the planning of street hierarchies similar to those we find in Tin Shui Wai today. Hong Kong s new town design limits commercial life and social activities to MTR station nodes and shopping malls. While they offer well-managed, air-conditioned and efficient environments, they are connected currently to a planning system of super blocks, car dominated distributor roads, and foot brides. The resulting city is fragmented by functions and social groups. The price is particularly high for low-income communities, which suffer even more from isolation and lack of opportunities. Economist Edward Glaeser reminded us that people moved from the countryside to cities for opportunities and choices (Glaeser, 2011). Cities flourished as they brought together different people to live in close proximity, offering connectivity and exchange. Hong Kong s early districts with integrated street networks and flexible typologies are living examples of how urban proximity, connectivity and diversity help generate multiple synergies. But while these qualities are gradually fading in those older districts, they are no longer celebrated in Hong Kong s recent new towns such as Tin Shui Wai and LOHAS Park. As Hong Kong embarks on designing its next generation of new towns, the inherent opportunities for synergies should be reconsidered, in the combination of integrated street networks, streetcars, and mixed-used typologies. In 9 A similar but legal market exists along Berlin Kreuzberg s Maybach Ufer and has become one of the biggest attractions of the district, where the local Turkish community mingles with university students and general visitors. The market gives the diverse district a sense of collective identity and pride, and successfully activates the surrounding streets. It also provides residents with locally produced food and is thus a successful example for a green and social city. 17

114 this context, Hong Kong s older districts merit fuller research and understanding of their urban qualities to inform the design of new developments and to avoid the apparent failure of recent ones as noted in this paper. Figure 10: Sai Ying Pun Street Space After Recent Transformation Left Street Side: The New Urban Renewal Project Island Crest, Photo 2013 REFERENCES Alexander, C., A city is not a tree. Design, London: Council of Industrial Design, 206. Bouffard, D., Cook, S., Eisenberg, S., and Mowris, R, Investigating the Relationships between Urban Design, Microeconomics, and Livability: A Case Study of Hong Kong. Advisors: Liang, J.Y. and Nikitina, S., Sponsors: Govada, S. and Tieben, H., CUHK. Worcester: Worcester Polytechnic Institute. Cassey, B., From Mansions, To Cages, To Coffins Hong Kong s Rotten Property Ladder, The Global Mail, June 24th, 2013, Chan, E., Voices of Tinshuiwai Women. Hong Kong: Mguru Ltd.. Chui, E., Lessons Unlearned Planning Disaster and Community Anomie. Asia Pacific Journal of Social Work and Development, 18(2), Condon, P.M., Seven Rules for Sustainable Communities: Design Strategies for the Post- Carbon World. Washington, Covelo, London: Island Press. 18

115 Gayle, D., Cage dogs of Hong Kong: The tragedy of tens of thousands living in 6ft by 2ft rabbit hutches - in a city with more Louis Vuitton shops than Paris. Daily Mail, January Glaeser, E.L., Triumph of the city: how our greatest invention makes us richer, smarter, greener, healthier, and happier. New York: Penguin Press, Govada S., 2011, Ten Principles for a Sustainable Approach to New Development: Towards Sustainable and Integrated Large-Scale Developments for a More Livable Hong Kong. Washington, D.C: Urban Land Institute ( Govada S., 2012, ULI Calls for a City Champion: Realising ULI 10 Principles for Sustainable Development for a more Livable Hong Kong, ULI SAND STAGE II: Draft Recommendations, Urban Land Institute ( Jacobs, J., 1992, The death and life of great American cities. New York: Vintage Books. Leeming, F, Street studies in Hong Kong: localities in a Chinese city. Hong Kong; New York: Oxford University Press, Lo K.C., Chinese Face/Off: The Transnational Popular Culture of Hong Kong, University of Illinois Press. Ng, E., Term Consultancy For Air Ventilation Assessment Services. Final Report Sai Ying Pun & Sheung Wan Area. Hong Kong: the Chinese University of Hong Kong. Ng Y.H., Cage homes fuel Tuberculosis in Sham Shui Po. South China Morning Post, 14th August, 2012, Smart, J., The political economy of street hawkers in Hong Kong, Hong Kong: Centre of Asian Studies, University of Hong Kong. Soja, E.W., Thirdspace : Journeys to Los Angeles and Other Real-and-Imagined Places. Cambridge, Mass.: Blackwell. Swift, P., Residential Street Typology and Injury Accident Frequency. Longmont, CO: Swift and Associates. Tieben, H., Woo, P.L. & Yuet T.C., Development or Destruction? The Transformation of Sai Ying Pun. Pearson, V. and Ko T.K. (eds.), A Sense of Place: Hong Kong West of Pottinger Street. Joint Publishing Company Limited, Hong Kong, Tieben, H., Public/Private Interfaces in Hong Kong: Observations in the Sai Ying Pun District. Radović, D. (Ed.). Mn M Workbook 1: Intensities in Ten Cities, International Keio Institute & Flick Studio, Tokyo. Whyte, W.H., The Social Life of Small Urban Spaces, The Conservation Foundation, Washington DC. Whyte, W.H., The essential William H. Whyte. LaFarge, A. (ed.), New York: Fordham University Press. 19

116 SUSTAINABILITY MODELLING FOR NATURAL DISASTER AFFECTED CITIES IN JAPAN Dr. Thomas Tang Corporate Sustainability, AECOM Hong Kong 12/F, Tower 2, Grand Central Plaza, 138 Shatin Rural Committee Road, Shatin, New Territories, Hong Kong Risa Onishi Environment, AECOM Japan 8th Floor, Kojimachi Square Plaza, , Kojimachi, Chiyoda-ku, Tokyo , Japan Mansi Sachdev Planning Design and Development, AECOM India 9th Floor, Infinity Tower- C, DLF Cyberciti, DLF Phase 2, Gurgaon, India 1

117 SUSTAINABILITY MODELLING FOR NATURAL DISASTER AFFECTED CITIES IN JAPAN ABSTRACT Natural disasters have devastating effects on cities. The recovery from disaster is not easy and there are many difficult choices that affected cities must make in rebuilding communities and restoring economic vitality. AECOM carried out a comparative review of 54 cities using global indices on sustainable and liveable cities to find an optimum model for the tsunami affected cities in Japan. The comparison focused on topics such as land use, public transportation and transit, waste management, water treatment and recycling, greening, reforestation, health care and renewable energy. In total, 24 sustainability initiatives were identified and grouped around ten major themes. The lessons learnt from this holistic approach were analyzed from the perspective of how key measures could be implemented to rebuild a disaster affected community. The study looked at economic returns, community revitalization, healthcare and social welfare, the tourism sector, energy/environment issues and building disaster resilience in the future. An economic sustainability model was developed around industry clusters and the effect of demand conditions, supporting industries, private company strategies and government policies. Keywords: NATURAL DISASTER; SUSTAINABLE CITIES; REVITALIZATION; ECONOMIC SUSTAINABILITY MODEL, JAPAN. 1. INTRODUCTION On Friday 11th March 2011, a powerful earthquake (magnitude 8.8) struck Japan and triggered a massive tsunami off the north east coast in the Sendai area that swept almost everything that came in its path. The devastation caused by the tsunami took several thousand lives, destroyed buildings and infrastructure, disrupted power systems (including the Fukushima nuclear power station) and tore communities apart. In the process of rebuilding, Hitachi Consulting, subsidiary of a Japanese company renowned for its innovative technology products, commissioned AECOM to carry out a review of sustainable cities to find out what models could be applied to rebuild affected cities as well as measures that would revitalize existing Japanese cities. AECOM carried out a comparative review of 54 cities using global indices on sustainable and liveable cities to develop an optimum model based on current initiatives and practices of economically sustainable cities worldwide. Key factors were identified that contribute to the broader vision of sustainable urban development, which would assist urban planning authorities of various cities in Japan. 2. STUDY APPROACH AND METHODOLOGY The methodology of this study comprised a desk top survey of existing city sustainability and environmental performance indices and programs to generate a list of global cities to compare sustainable initiatives. AECOM reviewed published sustainability indices and programs available on the internet, including sustainable cities programs, liveable cities programs, and indices of economic sustainability as well as measures of economic activity and growth and environmental impacts. The aim was to identify a list of cities with successful sustainability strategies. As existing rating systems use a range of different metrics for ranking a city, focusing on different aspects of sustainability such as environmental factors, community liveability, economic drivers, transportation systems, etc., the study deliberately avoided attempting to collate and rationalize metrics, but instead to identify cities for review. In total, a final list of 54 cities was selected for comparison. The comparative analysis considered a range of factors and sustainable initiatives within each urban area e.g. GDP per capita, tourist figures, economic anchor industries, 2

118 education, transport ridership, recycling, water consumption, carbon emissions per capita, green space per capita and smart growth. Figure 1 Distribution of Cities by Location and Size 3. STUDY FINDINGS For cities to achieve economic viability there are two major criteria: resource availability and economic drivers. Resource availability impacts political stability and public security (water and energy are prerequisites for any settlement to be successfully established). In resource-rich cities, the economy is driven by strategic investment in key industries and supporting factors such as education, healthcare and available housing for the workforce. High standards of quality of life, through investment in environmental protection and provision of space for enjoyment and leisure as well as for commercial purpose, attract talented workforces. But often these are not in balance as environmental quality (air, water, waste etc.) is compromised for economic development. Cities that have managed to strike such a balance can be counted as successful. We look at how different sized cities have managed to achieve economic viability. Large cities evolve through different stages of economic development. Global supply chains have lifted some cities from low value industries such as manufacturing and agriculture to higher value-added industries such as financial services and trading. Large cities attract investment and people. This influx of people encourages diversity, which in turn promotes innovation. However, growing populations often increase resource consumption resulting in stresses which include deteriorating water and air quality. Large cities hence tend to channel their efforts into developing infrastructure that will support their populations, e.g. efficient public transportation networks that have high ridership. A notable problem that large cities face is that of urban sprawl. Medium cities tend to reach a critical size based around a core industry, beyond which it is not in their interests to grow. Often the model is geared around a cluster of companies making the city a recognized leader in a particular field. There is emphasis on quality of life issues like environmental protection, education and healthcare to attract high calibre professionals as well as provide family friendly settings. Medium cities furthermore have flexible systems to change with market trends and policies and incentives to promote agile entrepreneurial business models. In terms of infrastructure, medium cities exhibit a good road network which allows extensive use of automobiles where people choose to drive due to poor connectivity of public transportation systems. With increasing awareness about sustainability, there is interest in expanding public transportation networks to regional transit routes. Medium cities also act as centres for research and development. The economies of small cities are founded on niche industries such as tourism or culture. In most cases, there are resources that are unique to the city e.g. scenic features or natural phenomenon like hot springs or slopes that draw investment and visitors; in some cases shifting from a sunset industry like mining to a more lucrative one like cultural tourism. This shift is accompanied by retraining of the local workforce to develop value added support services e.g. catering and hospitality for the main industry. The exclusivity of a small city is a critical success 3

119 factor hence development of infrastructure in mass mobility tends to not be a major investment. Small sustainable cities share certain common characteristics that allow them to stay sustainable. For instance, university towns are where local industries are geared towards student needs; others are tourist resorts; and a third category consists of experimental cities where it is possible to test new small-scale initiatives. Table 1 summarises the lessons learnt for developing sustainable city models. 4. DISCUSSION The Porter Diamond Model is an economic model that has been used to explain why certain industries become competitive in a particular location through industry or business clusters, where the competitiveness of a single company is related to the performance of other companies and a number of economic factors. A business cluster hence is a geographical concentration of interconnected businesses, suppliers and associated institutions, which can increase the productivity of companies and how they can compete, nationally and globally. Clusters of industries are tied together in a value-added chain, in customer-client relations and in a local or regional context. Understanding a city s clusters is an important aspect of strategic management of the community s sustainable economy. The key phenomena are classified into six broad economic factors or determinants of competitiveness and are incorporated into the Porter Diamond. Government Firm Strategy, Structure and Rivalry Factor Conditions Demand Conditions Chance Related & Supporting Industries Figure 2. Porter Diamond Model 4

120 Table 1. Lessons Learnt from Comparative Review of Sustainable Cities Sustainable Building 2013 Hong Kong Regional Conference Theme Lessons learnt Implementation Promoting sustainable 1. Build on local assets Set up focused towns e.g. R&D towns, tourist towns, and university towns economic 2. Promote green economic development Establish green business programs and green home schemes development 3. Attract new investment Ensure family-friendliness through high quality of life and subsidies for education Shifting to sustainable transport Implementing smart growth planning Shifting to clean energy Creating sustainable infrastructure Employing smart technologies Creating liveable communities Encouraging healthy communities Promoting leadership and public awareness Preserving environmental habitat and open spaces 4. Local and regional connections Develop flexible and accessible transit systems 5. Multiple modes to enable shift to transit Encourage pedestrianisation as well as alternative and non-motorised transport modes connected to transit hubs 6. Clean fuels for vehicles Shift to CNG/LPG/Biofuels 7. Other innovative tools and techniques Examples: smart road, congestion pricing, swipe cards, mobile phone applications and passenger systems, corporation shuttle programs, and car sharing 8. Integrate regional and local planning systems Regional scale planning to coordinate land use planning and transportation improvements 9. Implement transit oriented development (TOD) Concentrate high intensity development within short walking distance to transport centres 10. Densify urban core Increase mixed use development at key locations in city along transit lines, major growth corridors and arterial streets 11. Habitat and agricultural preservation Preserve areas for natural habitats, open space, recreation and agricultural uses - coordinated with urban development policies 12. Migration and immigration policy Encourage diverse and multi-cultural city populated by dynamic workforce 13. Cut high energy use in buildings Establish government building requirements for new buildings and retrofitting with incentives for energy efficient appliances supported by energy audits 14. Use of renewable and low carbon energy sources Examples: wind, solar, geothermal, tidal, bio-fuel, hydro-power and waste to energy 15. Innovate and implement green infrastructure Examples: water recycling, rainwater harvesting, waste segregation, waste pricing, composting, district heating 16. Automated smart management systems Examples: networks, sensors, electronics integrated with computerised control and communication systems and databases Set up vibrant communities where people want to participate e.g. family friendly, green, open spaces, multi-cultural venues 17. Culture, social events, sporting events and programs 18. Create facilities for healthy communities Set up sports fields, gyms, playgrounds, cycle paths, and walkways 19. Provide world class medical care Provide comprehensive medical facilities as well as childcare and elderly care programmes 20. Designing a differently-abled friendly environment Provide universal access for physically challenged, children and elderly 21. Practise organic and urban agriculture Examples: farmers markets, home grown produce, community gardening and organic farms 22. Establish community sustainability champions and Promote strong leadership and political will; identify green champions departments 23. Inform and involve community Examples: public campaigns, advertising and corporate campaigns 24. Habitat restoration Designate restricted areas for repopulating flora and fauna; set up genome banks 5

121 In the Porter Diamond Model, these special economic factors interact with each other to create conditions where innovation and improved competitiveness occur for an industry cluster in a specific location. While this economic model is commonly used to evaluate the competitive performance of national economies, the model has been applied to cities to help identify some of the key factors that may contribute to maintaining more economically sustainable communities. In table 2, we look at how the model applies to some of the focus cities identified in the review: Tourism/ outdoor College town Agriculture Knowledge-based 5. APPLICATION OF FINDINGS Economic revitalisation of Japanese cities is necessary for Japan s sustainable development. Lack of capital for building new and renovating old infrastructure mean that Japanese cities are slipping into urban blight and integrated regional planning of cities is essential to elevate the country s economy to generate vibrant and dynamic city centres. Furthermore, Japan s past history is marked by natural disasters. The occurrence of earthquakes exposes cities to the risk of natural disaster, making preparedness a pressing issue. The other major natural disaster likely to impact Japan in the future is climate change, which will have potentially catastrophic effects as violent events like strong winds, severe rainstorms and droughts will become commonplace. Ultimately Japanese cities must be climate-proofed, which will entail designing buildings and other infrastructure to be climate resilient in the future. To analyse the lessons learnt from the Japanese context, the vision statements 47 prefectural capitals in Japan were studied to identify the issues/challenges they are facing. From this, AECOM identified a number of key factors to analyse against the lessons learnt. Japan has various existing assets and potential tourism destinations that are not fully recognized due to transportation and branding shortcomings. Rural cities in Japan often have local festivals (matsuri) that have been practiced historically and enjoyed by the local population. Promotion of these festivals may be a new industry in the rural areas. Many small Japanese cities are losing populations to bigger cities, leaving behind the aged population, affecting the tax revenue and increased healthcare/social welfare fees. Densifying the urban core for small cities may be effective for bonding different kinds of people e.g. communities with different generations to help each other, create new learning opportunities and develop effective security and disaster prevention practices. The incident at the Fukushima Nuclear Power Plant has highlighted Japan s energy vulnerability and cities are focusing on creation and usage of renewable energy, with help from municipal governments. The new feed-in tariff scheme is expected to accelerate the implementation of renewable energy in Japan. With the energy crisis, more buildings and products will be expected to be energy efficient providing business opportunities and revitalising the economy. Japan has 87 district heating enterprises serving 148 districts. Many companies operate district cogeneration facilities that provide steam and hot water. Creation of a healthy community is vital in city development in Japan. The ageing population will keep on growing in Japan, while birth rate is declining, and cities would have to provide facilities and means of transportation to meet these issues. Providing daily exercise opportunities for both young and elderlies would be a preventive measure to decrease expenditure on healthcare. 6

122 TYPES OF CITIES STUDIED TOURISM/ OUTDOOR COLLEGE TOWN AGRICULTURE KNOWLEDGE- BASED FACTOR CONDITIONS Factor conditions are human resources, physical resources, knowledge resources, capital resources and infrastructure. Natural resources e.g. slopes, marine areas, hot springs. Established academic Institutions. Strong brand and Reputation. Good quality of campus life. Strong farming background, lush and fertile land. Unique and distinctive food products. Critical mass of retired professionals. Housing and living conditions above average. Table 2. Determinants of Success for Different Types of Cities According to Porter s Diamond DETERMINANTS OF SUCCESS DEMAND CONDITIONS RELATED AND SUPPORTING FIRM STRATEGY, GOVERNMENT Demand conditions in the INDUSTRIES STRUCTURE & RIVALRY Government can influence home market can help Related & supporting industries Firm strategy, structure and the supply conditions of companies create a can produce inputs which are rivalry determine the way in key production factors, competitive advantage, when important for innovation & which companies are created, demand conditions in the sophisticated home market internationalisation. These set goals and are managed. The home market, and buyers pressure firms to industries provide cost-effective presence of intense rivalry in competition between innovate faster and to create inputs, and they participate in the home base is also firms. more advanced products than the upgrading process, thus important; it creates pressure to those of competitors. stimulating other companies in innovate in order to upgrade the chain to innovate. competitiveness. Domestic and international tourists drive up service quality Standards. Domestic and international education seekers will insist on a high quality of academic excellence. Healthy lifestyle seekers and organic food devotees will be highly selective on choice of food. Demand from local industries seeking knowledge transfer will be choosy on service providers. Culture and heritage industries can co-exist with tourism. Also support service industries like hospitality, F&B, transport, cottage craft. Culture and heritage industries can co-exist with education. Also support service industries like book stores, F&B, entertainment. Culture and heritage industries can co-exist with farming. Also support service industries like event management, F&B, hospitality, retail outlets, cottage craft. ICT industries. Business centres. Emphasis on service quality. May leverage on technology applications for marketing and operational efficiency. Emphasis on academic excellence. May leverage on commercial applications of academic research e.g. business schools, research parks. Emphasis on traditional farming knowledge. Leverage on supply chains to get produce to retail outlets. Emphasis on knowledge and intellectual offerings. Leverage on technology enablers. Government can provide land, public infrastructure, subsidies and tax breaks. Also set up school of hospitality to train local labour force. Also set up museums, libraries, cultural centres. Government can provide land, public infrastructure to support citizens. Also set up museums, libraries. Also make it conducive for philanthropic donations. Government can provide land, public infrastructure, subsidies and tax breaks to local firms. Also set up school of agriculture to train local labour force. Government can provide public infrastructure, and tax breaks to individuals CHANCE EVENTS Chance events are occurrences that are outside of control of a firm. They are important because they create discontinuities in which some gain competitive positions and some lose. Opportunities are: Favorable currency exchange rates. Threats are: Climate change affecting natural resources. Opportunities are: Investment interest by companies to seek talent from pool of academics. Threats are: Technology providers offering online courses. Opportunities are: Use of technology to improve efficiency. Threats are: Climate change, blight. Opportunities are: Industrial revolution/ technology wave. Threats are: Financial crisis. 7

123 The implementation of smart technology allows effective usage of resources, for example, the increased demand of healthcare may be available through smart technology without having to physically go to a hospital. Also, smart technology can be applied from a disaster prevention perspective, such as earthquake-absorbing structures and systems for uninterruptible power supply. Community and stakeholder engagement can be seen in various examples, Not only does sense of ownership arise from participation, but engaging in the programme also serves as a catalyst to connect the different age groups, increasing interaction, thus improving the social welfare of the community SATOYAMA is a Japanese term made up of SATO-area inhabited by people/homeland and YAMA-mountains. It is used to describe a landscape comprising various ecosystems where people manage the land to make a living, showing the coexistence of nature and humans. Restoration of the SATOYAMA gives benefits to people, including food, forest products, non-timber forest products, economic, cultural, spiritual, and aesthetic senses. Table 3 shows the priorities for Japanese cities according to the 24 lessons learnt. Table 3. Priorities for Japanese Cities According to Lessons for Sustainable Cities Lessons learnt Key factors for cities H= High M = Medium L = Low 6. CONCLUSIONS The following conclusions can be drawn from the case studies presented. Transformational versus Evolutionary - Changes to some communities have been transformational, brought about by radical changes in the local industries or the need for revitalization e.g. declining industries. In other cases, the changes have been evolutionary. Farming practices, for instance, have transitioned from growing for self-sufficiency into commercializing organic produce. College cities with an established tradition have evolved into hubs of academic expertise and hence geared economic activities around colleges and scholastic centres. Synergistic Relationships - Some cities have adapted natural resources with features of great beauty such as slopes and marine areas for skiing and fishing respectively. The key is to match the right types of labour and skills to support industries geared around such outdoor activities along the entire value chain-from marketing to bringing in customers to the destination, to the delivery of the experience. Such activities must be aligned and coordinated and capacity must be built within the cities otherwise this synergy breaks down. Cluster Effect - The cluster effect causes industry standards to improve which is good for the customer as the quality of products and services is guaranteed, prices are competitive and choices are wider. For tourist cities, this means that visitors can expect good value for each trip in terms of organization and management, hospitality and service quality, and they will continue to return. The cluster effect further works for demographic groups as well, e.g. ageing populations, where the grouping of retired professionals with extensive knowledge 8

124 and industry experience provides a rich base of service providers e.g. consultants and technicians. Supporting Facilities - All cases indicate that the common supporting facilities are land, education and transit. Government policies and investment in these supporting facilities are essential if the city is to succeed. Other supporting facilities to a lesser but growing extent are ICT and smart infrastructure. Long-term Challenges - In the long term cities still have to be constantly striving to find new ways to innovate. Rising costs often affect successful cities, driven by inflation as well increasing costs of land and property. These factors affect the costs of living. The costs of maintaining ageing infrastructure will be a further challenge. Table 4. Proposed Sustainable Initiatives for Japanese Cities Regional Level/national level Local Level Multi-modal transportation improvements Local programs for recycle, reuse and Alternative, renewable power generation reduce (wind, geothermal, wave technologies, etc.) Local incentives to create green Regional programs to promote buildings development and tourism Promote urban farming, green roofs, Development of new education/research community gardens centres Localized public transit initiatives Promote higher intensity/density development at transit nodes Elderly programs 7. REFERENCES Economist Intelligence Unit (2011), A Summary of the Liveability Ranking and Overview: August 2011 Carbon Disclosure Project/AECOM (2012), Measurement for Management: CDP Cities 2012 Global Report Mercer (2011), Quality of Living Survey Worldwide City Rankings Economist Intelligence Unit/Siemens (2011), African Green Cities Index: Assessing the environmental performance of Africa s major cities Economist Intelligence Unit/Siemens (2011), Asian Green City Index Economist Intelligence Unit/Siemens (2011), European Green City Index Economist Intelligence Unit/Siemens (2011), Latin American Green City Index Economist Intelligence Unit/Siemens (2011), US and Canada Green City Index McKinsey Global Institute, McKinsey & Co. (2011), Urban world: Mapping the Economic Power of Cities The Brookings Institution, Global Metro Monitor (2012), Volatility, Growth, and Recovery, Metropolitan Policy Program Institute for Urban Strategies/The Mori Memorial Foundation (MMF), (2011) Global Power City Index Asian Development Bank (2011), Asian Cities Report European Green Capital, Ambiente Italia (2010), Measuring Urban Sustainability: Analysis of the European Green Capital Award Porter, M.E., (1990), The Competitive Advantage of Nations. New York: Free Press. The authors would like to acknowledge with thanks the contributions of the following colleagues: Apoorva Alankar, Saon Bhattacharya, Siet Ling Chong, Helena Fu, Amireeta Kumari, Sumati Rajput, Pooja Singh, Paul Tuttle, Seimei Yamamoto. 9

125 PLANNING FOR BETTER URBAN CLIMATE C K SOH, Chief Town Planner 1 Planning Department, Hong Kong SAR Government, Hong Kong 1 Corresponding Author udlpd@pland.gov.hk, Tel: (852) , Fax: (852)

126 PLANNING FOR BETTER URBAN CLIMATE ABSTRACT The pace and intensity of development over the past decades has led to deteriorating urban winds and accelerating urban temperatures in Hong Kong, bringing with it considerable public health, environmental and socio-economic externality costs. As a high-density city in the sub-tropics, Hong Kong has longed for a planning strategy to address such urban climatic concerns. The Planning Department s Urban Climatic Map and Standards for Wind Environment Feasibility Study is a territorial-wide scientific research study to examine the root causes of the intensifying Urban Heat Island effect in Hong Kong. Through years of quantitative investigations, technical parametric studies and collaborations with the world s leading academics in the field, the study has unveiled a comprehensive overview of the urban climatic characteristics of the territory based on the interplay of thermal load and dynamic potential factors calibrated against human thermal comfort levels. The centrepiece of the study is the Urban Climatic Planning Recommendation Map ( UC-ReMap ), which is an information platform compiled through balancing urban climatic, planning and design considerations against the local context. Through promoting an urban climatically-conscious approach in planning and design, the study recommendations will be important in shaping future development practice in Hong Kong at the district and strategic levels. Planning and design measures are devised to provide general guidance to tackle urban climatic issues. Specific benchmark standard for air ventilation assessment is drawn up for assessing development projects which may have air ventilation impacts. At a strategic level, the planning and design recommendations of the UC-ReMap will prescribe preservation, improvement or mitigation measures to ensure a better urban climatic environment. Moreover, the recommendations will aid future planning reviews and help pinpoint key areas for future development an approach already employed for the New Development Areas in the New Territories. Keywords: Hong Kong; Planning; Urban Climate; Urban Heat Island; Air Ventilation. 1. INTRODUCTION Hong Kong is one of the most densely populated cities in the world. With a total land area of about square kilometres, its population in 2012 was over 7.15 million, i.e persons per square kilometre. The development density is in fact much higher as over two-thirds of the land area, about 740 square kilometres, is natural landscapes, among which nearly 60% have been designated as Country Parks. We have so far been enjoying the advantages of this high-density living: there is much convenience in our daily lives with different facilities and services within close range; in turn, a majority of land with conservation value can be preserved; and concentrations of economic activities and people have enhanced productivity and innovation. A highdensity mode of development can also optimise the cost and efficiency of infrastructure provision, for instance, we have one of the world s most efficient public transport networks which lead to less reliance on cars i.e. about 90% of the commuters are using different means of public transport. 2

127 As a coin has two sides, this high-density living model does not lack its own challenges. One of them is Urban Heat Island (UHI) effect. Hong Kong is situated in the subtropical climate region with hot and humid summer months. Our urban area, with a high concentration of concrete buildings, paved surfaces and complex building morphology has a much higher thermal capacity than the rural surroundings, meaning they store much heat during daytime elevating the temperature. At night, tall buildings block the sky view, limiting their ability to release heat back into the atmosphere. The residual heat is carried forward to the following day and the vicious cycle continues. The UHI effect contributes to uncomfortable urban living and increase in energy consumption. To alleviate the UHI effect, good urban air ventilation is an effective means providing for the much-needed thermal relief and comfort within the built environment. However, the pace and intensity of development over the past decades, as well as the legacy of old building design and layout with little consideration of urban climate in the past have increased the surface roughness of our urban area diminishing the free flow of air. Over years, we are experiencing higher urban temperature and weaker urban air ventilation. According to the Hong Kong Observatory (HKO), the rate of increase in average temperature in Hong Kong was about 0.16 degrees Celsius ( C) per decade between 1947 and Much of this temperature rise could be attributed to the retention of heat by the increase in extent of concrete structures. The HKO also recorded a sustained decrease in urban wind speed e.g. reduction by 50% between 1968 and 2005 recorded at the King s Park meteorological station. To promote sustainable urban planning and design practices, the Feasibility Study on Establishment of Air Ventilation Assessment System was carried out in 2005 which led to the promulgation of the current Technical Circular No.1/06 on Air Ventilation Assessment (AVA) in Since then, AVA has been applied to all major government projects which may have major impacts on the macro wind environment, including planning studies for new development areas and comprehensive redevelopment areas, preparation of new town plans and major revision to town plans. It is, however, acknowledged that further research on urban climate is necessary to refine the application of AVA in building design and layout, and to investigate the feasibility of setting up an urban climatic planning framework to facilitate Hong Kong s long-term development. 2. URBAN CLIMATIC MAP We have approached the subject from two fronts. At the territorial level, we need to have a better scientific understanding of urban climate and to map out the urban climatic situations in different parts of Hong Kong. To this end, a scientific study on urban climate tailored to Hong Kong s unique urban morphology and environment is required. Through scientific research, survey and testing, we would be in a position to devise practical planning strategy to facilitate decision-making and tackle the urban climatic issues identified with a view to improve urban climate in the long run. For district and site planning, the scientific study could provide insights on planning and design measures that are conducive to improving urban climate and thus should be observed in the planning stage. The study should also review and improve the current AVA mechanism for projects that may have potential air ventilation impact so as to better assess the pros and cons of different building designs and layouts. 3

128 With these objectives in mind, the Planning Department commissioned the Urban Climatic Map and Standards for Wind Environment Feasibility Study (the UCM Study) in It is a territorial-wide research study to comprehensively and scientifically assess the urban climatic characteristics of different parts of Hong Kong and to formulate holistic planning and design measures to achieve long-term improvement of the urban living environment. Drawing upon international experience, in particular the Urban Climatic Map System of the Stuttgart Federation in Germany and the Environmental Map for the Tokyo Metropolitan in Japan, various analyses of existing urban climatic and wind environment characteristics and verification/calibration of different planning and design measures have been conducted using wind modelling, wind tunnel benchmarking studies, model simulations, and field measurements etc. Planning data and climatic data are combined, analysed and interpreted in the form of Urban Climatic Map (UC Map). Simply put, UC Map is an information tool that integrates urban climatic factors and town planning considerations to assist planning decisions. UC Map consists of two main components, viz. Urban Climatic Analysis Map (UC-AnMap) and Urban Climatic Planning Recommendation Map (UC-ReMap) UC-ANMAP UC-AnMap maps out the spatial relationship between the variation in the city fabric that affect thermal load and dynamic potential in relation to human thermal comfort. Thermal load measures the stored or emitted heat intensity in particular localities. A major negative factor which will increase thermal load is building volume, whilst topography and green space are positive factors. Dynamic potential is evaluated on the basis of ground roughness and therefore the availability of wind and cold air mass exchange. A major negative factor which decreases air ventilation is ground coverage, whilst natural landscape and proximity to openness are the main positive factors. Figure 1: Making of the UC Map Human thermal comfort at pedestrian level is the focus of planning for better urban climate and it can be quantified using Physiological Equivalent Temperature (PET). PET reflects the heat balance relationship between human body and its immediate surroundings, and is influenced by a combination of environmental variables and 4

129 physiological inputs, including air temperature, solar radiation, relative humidity, wind speed, clothing, and metabolism etc. According to user survey, the neutral PET (i.e. neither too cool nor too warm) for Hong Kong under the summer condition is 28 C. The six key geographical and development factors affecting thermal load and dynamic potential mentioned above are weighted according to their effects on increasing or decreasing PET. The resulting PET value denotes the net effect of these factors on the urban climate in particular locations and the information was mapped out for the whole territory. Based on the analysis and evaluation, the urban climatic factors are then translated into eight different climatic classes subject to different impacts on human thermal comfort. Figure 2: Urban Climatic Analysis Map To finalise the UC-AnMap, a wind information layer is incorporated showing the wind environment of different parts of Hong Kong in the summer months based on long-term wind data collected at 40 HKO weather stations and supplemented with MM5-CALMET modelled wind simulation data UC-REMAP The urban climatic information collated in the UC-AnMap are then further evaluated and interpreted to formulate the UC-ReMap, which is an information tool that integrates urban climatic factors with town planning considerations. The eight climatic classes were consolidated into five Urban Climatic Planning Zones (UCPZs) in accordance with their similar urban climatic characteristics with respect to the human thermal comfort and planning implications. 5

130 Figure 3: Urban Climatic Planning Recommendation Map Based on the UC-ReMap, urban climatically valuable or sensitive areas in need of retention/improvement could now be identified at a district level to provide guidance in the preparation and review of town plans. It also helps identify suitable locations for new development as well as evaluate broad urban climatic effects of major planning and development proposals. The UC-ReMap also identifies city climate areas with different ventilation systems and key summer prevailing wind directions, channelling winds, sea breezes and downhill air movement areas, which provide an indication as to where potential breezeways, air paths and setbacks/non-building areas should be located and how they should be orientated and connected at the district planning level. It is important to note that the UC-ReMap has been compiled from information in 100m x 100m grids with an assumption of homogeneity within each grid. As such, the map should not be read pixel-by-pixel or be used literally for site-specific reference and application. Rather, the emphasis should be on the pattern, clustering and extent of similar urban climatic characteristics to give a better understanding of the general characteristics of an area/district concerned. In drawing up planning and development proposals, due regard should be given to other relevant considerations, such as social and economic factors, as well as the site context URBAN CLIMATIC PLANNING ZONES For each of the five UCPZ, broad strategic planning recommendations at a district planning level are formulated based on an understanding of the urban climatic characteristics of the area in relation to thermal load and dynamic potential, and the impact on human thermal comfort: 6

131 UCPZ 1: mainly covers natural vegetation areas at higher altitude with minimal obstructions to wind. As their cool air production capacity is beneficial to adjoining urban areas, they should be preserved as far as practicable. The majority of this zone is currently subjected to different statutory controls such as country parks and conservation-related zones designated on statutory town plans. Small-scale and essential developments may be allowed with careful planning and design. UCPZ 2: covers areas which are, at present, urban climatically neutral in terms of urban thermal comfort, and the general urban climatic characteristics should be maintained as far as possible. They mostly cover urban fringe areas or rural lowland. New comprehensive development is possible subject to thorough urban climatic consideration. UCPZ 3: covers areas which are currently subject to urban climatically moderate impact in terms of urban thermal comfort. They are mostly in the urban fringe or less dense development areas. Some mitigation actions are encouraged where possible. Additional development is permissible subject to satisfactory compliance with prudent planning and design measures. UCPZs 4 and 5: are the densely built-up areas, including most of the new town areas and the metro areas at the northern part of Hong Kong Island, Kowloon Peninsula and Tsuen Wan. Existing developments in these areas have already had a strong to very strong impact on thermal comfort, typified by high thermal load and low dynamic potential. Mitigating measures, such as maximisation of greening and preservation of air paths, are considered essential. Intensification of use/additional development is not recommended unless with appropriate mitigation measures. With the benefit of the UC-ReMap, planners are now provided with a strategic and comprehensive urban climatic planning framework and information platform to guide the future planning and development of Hong Kong. In general, while further developments are possible within the more sensitive UCPZs 4 and 5, appropriate mitigation measures are necessary to prevent further degrading of the urban climatic condition. On the other hand, UCPZ 2 provides opportunities for new large-scale developments where planning and urban design measures including breezeways, air paths, street grids and building disposition etc. that are conducive to urban climate could be comprehensively laid out. In this connection, the New Development Areas in North- East New Territories and Hung Shui Kui, both falling within UCPZ 2, have been correspondingly targeted and are currently being studied for comprehensive developments. 3. SIX PLANNING AND DESIGN MEASURES TO IMPROVE URBAN CLIMATE During the preparation of the UC-ReMap, a number of key factors affecting thermal load and dynamic potential have been identified. Accordingly, appropriate planning and design measures are devised to provide general guidance to tackle these factors in planning stage to mitigate thermal load and promote air ventilation: Greenery A greening strategy to increase green coverage, preferably through tree planting at grade, is effective to enhance human thermal comfort in the urban environment. Creating urban green oases and establishing network or connected green corridors, ideally free of traffic, can allow resting points and more thermally comforting routes for pedestrian. Building Volume The higher the building volume, the higher the thermal load as the localised heat capacity is increased whilst the radiative cooling effect in city at night is 7

132 reduced. Tall buildings flanking narrow streets can limit urban air ventilation. Excessive floor-to-floor height, as well as excessive concessionary gross floor area will increase the building volume and hence increase the thermal load to the built environment. Building Height In general, gradation of building heights would help wind deflection and avoid air stagnation. Where appropriate, building height variation across the district and decreasing height towards the prevailing wind direction should be adopted to promote air movements. Excessive building heights increase ground roughness and reduce urban air ventilation in the air layer between the ground and the average building height. Proximity to openness and connectivity Urban space connectivity is very effective in promoting good air ventilation through the city. The free flow of air ventilation through the urban fabric can be enhanced by connecting the waterfront with the vegetated hill slopes through a connection of breezeways, air paths, open spaces, greeneries, green oases and green fingers. Various connection strategies can be considered such as designation/orientation of non-building areas perpendicular to waterfront/vegetated hill slopes. Ground Coverage High ground coverage of buildings in urban area significantly reduces the air space available for air ventilation. In areas where streets are narrow and ground coverage is high, it is important to consider measures such as providing non-building areas, building set back, reduction of frontage area as well as creating more open spaces so that the district average ground coverage can be lowered. Building Permeability Wall-like buildings will block urban air ventilation and create large wind wake areas where air is stagnant. Given the tall building morphology of urban Hong Kong, gaps between building towers and between the podium and the tower blocks above, especially near the pedestrian level, are useful design features. In fact, with the support of AVA, some of the above planning and design measures, such as regulated building heights, proximity to openness and connectivity of urban space, have already been adopted in the review of Outline Zoning Plans of various districts since 2007 to meet the community's aspirations for improving the living environment. 4. BENCHMARK STANDARD FOR AIR VENTILATION ASSESSMENT The UCM Study has established a practical wind performance criterion as a benchmark standard on AVA based on the scientific understanding of biometeorology, i.e. the heat balance relationship between the human body and its immediate surroundings. In short, if the body gains heat energy due to high air temperature and strong solar or environmental thermal radiation, then one will feel uncomfortable. On the other hand, if there are light winds blowing over the body, which carries some of the heat-gain away, one will feel more comfortable. On the streets of Hong Kong, the mean radiant temperature under shading in summer is typically at 32 to 34 C, taking into account the average humidity and solar radiation. According to the UCM Study, an increase of wind speed from 0.5 to 1.5 metre per second (m/s) has an effect of decreasing PET by about 2 C. To achieve the neutral PET of 28 C experienced by pedestrians, light air of 1 m/s would be necessary. The sensation would roughly equate to the waving of a fan against oneself. Balancing the desirable minimum wind speed according to benchmarking investigations and practical considerations of the existing built environment, a quantitative wind performance criterion for AVA is recommended at a level of overall 8

133 1 m/s within the assessment area for annual and summer median hourly mean wind speeds if the new/additional development is not going to further worsen the urban thermal climate. However, the desirable light wind situation especially in the summer months may be difficult to achieve in some areas of Hong Kong due to the existing topography and compact urban morphology, such as high-rise building towers, narrow streets, large building bulk and large podia, hence limiting site wind availability in an area. The UCM Study has analysed various factors affecting urban climatic situation as well as the current Buildings Department s Practice Notes for Authorized Persons (PNAP) APP-152 on Sustainable Building Design Guidelines, which sets out to promote sustainable building design measures through the provision of building separation, setback and greenery. In the event that the 1 m/s requirement is demonstrated to be practically not achievable after considering all possible and practical mitigation measures, an Alternative (Prescriptive) Approach, comprising the following four measures, could then be taken to help mitigate the urban climatic impact arising from individual developments: Ground Coverage of no more than 65%; Building Permeability (at tower block level) as per PNAP APP-152; Building Setback requirement near narrow street as per PNAP APP-152; and Greenery (preferably tree planting) of not less than:- 30% (for sites larger or equal to one hectare in size); or 20% (for sites of square metres or larger but smaller than one hectare in size). The greenery should preferably be at grade, in particular on the ground level. The Alternative (Prescriptive) Approach is based on the same scientific understanding of the UC Map. In essence, if all building sites in an area follow the same prescriptive approach, the collective and cumulative overall urban climatic condition would approach that of the 1 m/s requirement. 5. FOR OUR BETTER FUTURE Our unique building morphology and development intensity shape our remarkable city. In pursuing Hong Kong s continuous economic development and to meet the increasing demand of land for housing, office/commercial, schools and other uses by the community, planners have to devise appropriate planning strategies that could propel the momentum of economic and city growth and, in parallel, attain a sustainable and quality built environment. Through better understanding of the scientific basis and issues of urban climate and in mapping out the urban climatic situations in different parts of Hong Kong, we are now in a better position to identify new and strategic development areas at suitable locations to meet our demand for land and devise appropriate measures to mitigate environmental impacts to be brought about by high-density development in the main urban areas. Through concerted effort, the urban climate of Hong Kong as a whole could be improved in the long run. The crux is everybody has to do one s fair share towards a better common future. 9

134 FROM SUSTAINABLE BUILDING TO NET ZERO IMPACT SWIRE SUSTAINABILITY CASE STUDY Samuel Kwong 1, Group EHS Manager John Swire & Sons (HK) Ltd, Hong Kong 1 Samuel Kwong samuelkwong@jsshk.com, Tel: (852) , Fax: (852)

135 FROM SUSTAINABLE BUILDING TO NET ZERO IMPACT SWIRE SUSTAINABILITY CASE STUDY ABSTRACT Swire constructed its first office building in Hong Kong to the BEAM excellent rating in 2006 and has subsequently aimed to achieve BEAM Platinum rating for new buildings in Hong Kong and LEED Gold standard for new buildings in Mainland China. In 2010, its first LEED Platinum rated bottling plant was in operation in Luohe, Henan Province, PRC. The ultimate sustainable development goal of Swire is for its operating companies to achieve zero net impact on the environment. In 2012, a preliminary plan was developed for reaching this Net Zero goal through Reduce, Reuse and Replenish. The concept is to reduce and reuse as much as possible internally with the residual impact to be equalized through replenishing i.e. returning the resources which it consumes by supporting the projects of others and by making its own investments. Roadmaps for individual environmental aspect are drawn up accordingly to the Reduce, Reuse and Replenish concept. An accounting methodology is being developed to allow different environment aspects to be quantified and transferred across the company. To facilitate internal efficiency improvement, an energy committee has been established. Energy efficiency best practices were recorded and developed into protocols to facilitate self assessment. Cross-company energy audits have been conducted and potential savings of HK$2M were identified. A carbon desk was also established in 2012 to assess the carbon generating and investment opportunities. A sustainable development fund of 20M per year is established allocated since 2013 to finance projects that have excellent sustainability credentials but do not meet the economical hurdle. This paper will use real examples to demonstrate how sustainability strategy is developed and implemented, the challenges in implementation and steps to make sustainability main stream of business. Keywords: SUSTAINABLE BUILDING; BEAM; LEED; NET ZERO IMPACT; SUSTAINABILITY. 1. INTRODUCTION Swire Pacific is one of the leading companies in Hong Kong, with five operating divisions: Property, Aviation, Beverages, Marine Services and Trading & Industrial. The Group s operations are predominantly in Greater China, where the name Swire or 太古 has been established for over 140 years. The Group takes a long-term perspective in formulating strategy and this is reflected in the nature of investments. It recognizes that sustainable development does not mean less profit. Rather it is an opportunity to increase efficiency. Its ultimate goal is for its operating companies to achieve net zero impact on the environment. 2. SUSTAINABLE BUILDING DESIGN Swire Properties, a division of Swire Pacific, is a leading developer, owner and operator of mixed-use, principally commercial properties in Hong Kong and Mainland China, with a well established record of creating long-term value by transforming urban areas. It aims to be at the forefront of sustainable development by designing energy efficient buildings through innovative use of design, materials and new technology. It built the first office building in Hong Kong under the Building Environmental Assessment 2

136 Method (BEAM) excellent rating in 2006 and has subsequently aimed to achieve BEAM Platinum rating for new commercial and residential buildings in Hong Kong and Leadership on Energy Efficiency Design (LEED) Gold standard for new commercial and residential buildings in Mainland China. In 2008, it commenced to offer free energy audits to tenants to encourage efficient use of energy. The free audit service was extended to a local school in To further develop energy saving standards and guidelines in the usage of energy in property, an efficiency research fund with Tsinghua University in Beijing was established in 2008 and a joint research centre was established with Building Energy Research Centre of Tsinghua in Its latest target is to reduce energy consumption in its Hong Kong property portfolio by 50 million kwh from 2008 levels by If achieved, this will save approximately HK$66 million in annual electricity bills. Figure 1: Ten Years of Energy Efficient Thinking in Swire Properties In 2010, Swire s first Platinum LEED bottling plant was in operation in Luohe, Henan Province, PRC. In 2011, Cathay Pacific, Swire s aviation arm, opened its first lounge refurbished to LEED standard at San Francisco and has subsequently decided to follow a similar design approach for lounges refurbishment in the future. The company is now developing a policy to follow a minimum sustainable design standard for all its major future development and renovation projects. 3

137 3. NET ZERO GOAL Swire s principle is that sustainability is part of, not separate from, doing business. The decisions of each of its business unit take due account of the sustainability matters relevant to that unit, in the same way that they take due account of other relevant matters. Sustainability matters are taken into consideration when assessing risks and planning for the future. The outcomes of the decisions on sustainability matters are to be reported on by business units, just like any other business outcomes. Business units have sustainability targets which are reported in the group management accounts. The company s ultimate goal, which was first articulated in 2010, is for all its operating companies to achieve net zero impact on the environment. It aims to do this by investment, innovation and operational excellence. In 2012, a preliminary plan was developed for Net Zero implementation. The focuses of the plan are: To reduce carbon emissions, water consumption and waste production To reuse things consumed by treating and recycling, where possible returning them to the environment; and To replenish consumed resources by supporting the projects of others and by making appropriate investments. Figure 2: Swire Pacific Net Zero Strategy 3.1. WATER STEWARDSHIP An example of the Net Zero implementation is in Swire s beverage division. Water is the most important ingredient in beverages production. Swire s beverage division accounted for 72% of the total water consumption of the company in It has 4

138 pledged to be responsible stewardship by seeking ways to reduce water use in production and at the same time establishing partnerships that contribute to sustainable use of water in the communities where its business are located. In 2011, it used approximately 5.98 million litres of water, a 0.3% decreased compared with 2004, despite a 62% increase in production volume compared with the same year. This amounts to 39% improvement in water efficiency over the years. A water footprint exercise was conducted in Taiwan examining the water usage during the product life cycle for the production of a bottle of 600mL PET Coke. Opportunities to improve water usage across the supply chain were identified. To reduce the use of municipal freshwater, bottling rinsing water and treated water are recycled. Wastewater is treated to the level that supports aquatic life before discharges. In one of its bottling plants in China, treated wastewater is delivered to an artificial lake in a nearby city park for amenity use. This enables the city to save 200 million litre of fresh water every year. Figure 3: Water Stewardship in Swire Beverages A further and important component of the Net Zero is replenishment. In 2012, the company completed vulnerability assessments of the watersheds where its bottling plants are located and developed protection plans to mitigate potential risks associated with quality and quantity of water supplies. A fund was established in 2007 drawing 0.5% profit after tax or a minimum of HK$200,000 from each bottling plant every year for community investment. One of the key focuses of the fund is to carry out projects that can replenish the amount of water used in the product ENERGY EFFICIENCY INVESTMENT To facilitate internal efficiency improvement, an energy committee was established in It allows business units to share resources and best practices and to make plans for the attainment of the Net Zero goal. Energy efficiency best practices were recorded and developed into protocols to facilitate self assessment with the aim of developing ultimately into a curriculum to train up professionals and promote energy efficiency in the industry. Cross-company energy audits have been conducted and potential savings of over HK$2M were identified. The energy audit at Swire Resources has helped reduce the electricity consumption by 16%. Studies at Cathay Pacific City and Dragonair Building have identified potential savings of approximately HK$1M per year per building, mainly through efficient operation and maintenance of the air conditioning units. The company has piloted the use of a radiant cool ceiling technology in the administration building of Hong Kong Aircraft Engineering Company in the airport complex and has extended the 5

139 application in the Cathay Pacific Cargo Terminal Building subsequently. The technology has demonstrated a 40% energy saving comparing with conventional fan coil unit system and better comfort rating. A sustainable development fund of 20M per year was allocated since 2013 to finance projects that have excellent sustainability credentials but do not meet the economical hurdle. Guidelines have also been provided to the operating companies on the evaluation of energy efficiency project stressing the need of long-term approach. A carbon desk was also established in 2012 to assess the carbon generating and investment opportunities. Although the price of carbon is volatile and the administration cost to capitalize the carbon credit from energy efficiency projects is high, the study in this area through the carbon desk will make the company ready when such system becomes mandatory and the market picks up. The potential carbon credits will provide an additional source of benefit for the energy efficiency projects. An accounting methodology is also being developed to allow different environment aspects to be quantified and transferred across the company. Figure 4: Cross-company Energy Audit 4. SUMMARY The evolution of Swire s commitments on sustainable development from building design to Net Zero has demonstrated its long-term approach in investment. The endeavour towards Net Zero is and should be a process leading to sustainability not an end goal. The approaches Swire has taken in the Net Zero process could provide some references to business and authorities in managing our community or society towards sustainability. 5. REFERENCES Swire Beverages, 2010 Sustainable Development Report In Essence. from: Available Swire Pacific, Annual reports (2011 & 2012). Available from: 6

140 DESIGN RECOMMENDATIONS FOR NEW COURTYARD BUILDINGS IN COMPACT HISTORICAL CENTRE OF HAVANA Abel Tablada 1 Department of Architecture, National University of Singapore, Singapore 4 Architecture Drive, Singapore Corresponding Author akiaetdl@nus.edu.sg, Tel: (65) , Fax: (65)

141 DESIGN RECOMMENDATIONS FOR NEW COURTYARD BUILDINGS IN COMPACT HISTORICAL CENTRE OF HAVANA ABSTRACT The Historical Centre of Havana in Cuba is a compact low-rise urban site declared World Cultural Heritage in 1982 by UNESCO. The Master Plan of the Historical Centre comprises the construction of residential buildings in the empty plots to allocate surplus population from overcrowded houses and from dilapidated and valuable colonial buildings. However, the new housing typologies, while increasing the gross floor area in comparison with previous colonial buildings, should also ensure proper environmental conditions and thermal comfort by maximising the potential for natural ventilation. The aim of this paper is to present preliminary design recommendations for new low-rise residential courtyard buildings inserted in the Historical Centre of Havana. The recommendations are based on previous studies on microclimatic measurements, comfort survey, Computational Fluid Dynamics simulations, thermal simulations and comfort analysis on a series of combinations of courtyard building prototypes. The recommendations aim to promote the design of thermally comfortable naturally-ventilated residential buildings in the Historical Centre of Havana in particular and in other compact lowrise urban areas in tropical-humid regions in general. Keywords: Courtyard buildings; Design recommendations; Natural ventilation; Thermal comfort; Tropical architecture. 1. INTRODUCTION The Historical Centre of Havana (Old Havana) in Cuba is a compact urban site declared World Cultural Heritage in 1982 by UNESCO. It is located on the west side of Havana s harbour at north and west, very close to the Tropic of Cancer as shown in Figure 1. It has a density of 30,000 inhabitants per km 2 (National Office of Statistics, 2011) plus a floating population of 37,000 per km 2 in an area of 2.14 km 2. Climatic conditions in the city are influenced by the sea with a combination of relatively high values of air temperature (August mean maximum: 31.4 C) and high values of relative humidity (August mean maximum: 91%). With a distinguished wet and dry season, Havana belongs to the Tropical savanna climatic zone according to Köppen s classification. Despite the comprehensive recovering plan that has been undertaken during more than 3 decades in the Historical Centre, there is still a significant amount of buildings in disrepair and empty plots inside the boundaries of the former intramural city (Fig. 1c). The Master Plan of the Historical Centre (Office of the City s Historian, 1998) comprises the construction of residential buildings in the empty plots to allocate surplus population from overcrowded houses and from dilapidated and valuable colonial buildings. However, the new housing typologies, while increasing the gross floor area in comparison with previous colonial buildings, should also ensure proper environmental conditions and thermal comfort by maximising the potential for natural ventilation. The application of natural ventilation strategies helps to prevent the use of air-conditioners in the new housing, contributing in this way to diminish the energy use and the effects of the urban heat island and the green-house gas emissions at local and global scales respectively. 2

142 Numerous studies have proposed design strategies for buildings in tropical and humid climates. However, most of the design recommendations (e.g. Koenigsberg et al., 1973; Lippsmeier, 1980; Givoni, 1998) are based on the assumption that cities in such climates have spread-out low-density urban environments. In recent years several studies have focused on urban design guidelines for tropical high density and high-rise urban environments, especially for East Asia (e.g. Ng, 2010; Cheung and Liu, 2011; Yuan and Ng, 2012). However, nor the spread-out neither the high-rise urban environments are representative of Old Havana and other tropical cities in Latin America, Africa and Asia. Figure 1: a) Location of Havana, b) typical street in Old Havana, c) satellite view of the Historical Centre of Havana (inside doted lines is the former intramural city). At the building scale, most studies related to courtyard buildings considered hot and dry climates and focused on their thermal performance rather than on the airflow conditions. Literature related to courtyard buildings in tropical humid contexts is scarce. Bittencourt and Peixoto (2001) and Rajapaksha et al. (2003) performed CFD simulations for a building and a house with a courtyard. In addition, Murakami et al. (2004) conducted a study on a porous-type building for a compact urban area of Hanoi. However, in these studies the buildings are fully or partially isolated and have openings in their exterior envelope in contrast with the situation of the present study in which the courtyard building is located in a very compact urban environment with openings mainly in the inner courtyard walls. The purpose of this paper is, therefore, to present preliminary design recommendations for future low-rise residential courtyard buildings inserted in the Historical Centre of Havana. The recommendations are based on microclimatic measurements and a comfort survey reported in Tablada et al. (2009) and on Computational Fluid Dynamics (CFD) simulations, thermal simulations and comfort analysis (Tablada et al., 2006) on a series of combinations of courtyard building prototypes. 3

143 2. MORPHOLOGY AND PLOT TYPES The urban morphology in the Historical Centre can be described as compact low-rise. The street pattern is semi-orthogonal and the parcel system shown in Figure 2a is one of shared party walls with elongated plots. The buildings occupy most of the plot area leaving only 15% to 20% of open space for inner courtyards and air/light shafts. The oldest residential buildings have one (4 5 m high) or two stories (8 10 m), while the apartment buildings have three (9 12 m) or four (12 15 m) storeys. Plot ratios vary between 1.5 and 2.5. The street canyons are about 7 10 m wide having width/height (W/H) aspect ratios from 1.2 to 0.5 (Fig. 1b). The compact nature of the urban structure and the presence of party walls for almost all buildings allowed limiting the natural ventilation and thermal comfort study to a selected number of generic building and courtyard configurations. In Tablada et al. (2009) a morphological subdivision of the Historical Centre was made and three typical plots were selected from two representative sectors. Afterwards, potential building layouts for each typical plot were explored by using a horizontal modular grid for rooms and inner courtyards (Fig. 2b). The horizontal modules are 3.5 m by 3 m and determine the room and courtyard dimensions. The width (W) of the courtyard is 3 m, 6 m or 9 m and the courtyard depth is 3.5 m, 7 m, or 10.5 m. In the selected configurations, the buildings have three floors with a total height of 9 m. Figure 2: a) Typical urban block with courtyard buildings in Old Havana, b) three representative plot types with modular subdivisions. For the CFD simulations, cases with a single or a double courtyard were considered. The aspect ratios of the courtyards were W/H = 0.33, 0.66 and 1.0. For the thermal simulations and comfort analysis, the combination of a single room with its adjacent courtyard(s) was considered. For single-side ventilated (SV) rooms, four window orientations were considered: east-northeast (ENE), south-southeast (SSE), westsouthwest (WSW) and north-northwest (NNW). These orientations coincide with the actual orientation of building blocks in Old Havana. For cross-ventilated (CV) rooms, the two possible orientations were considered: ENE-WSW and SSE-NNW. 3. SUMMARY OF RESULTS FROM CFD AND THERMAL SIMULATIONS In this section the results from the natural ventilation and comfort studies in the generic buildings three storeys with one or two consecutive courtyards- inserted in the compact urban environment of the Historical Centre of Havana are summarised. CFD 4

144 simulations (by Fluent Inc, 2003) were performed to obtain the values of indoor air speed and pressure coefficients required for the thermal and comfort simulations (by EnergyPlus, 2001). Thermal comfort was analysed by using the extended Predicted Mean Vote (PMV) index adapted to regions with warm conditions (Fanger and Toftum, 2002). For a detailed description of the simulations methodology and results the reader is referred to Tablada et al. (2006) NATURAL VENTILATION EVALUATION USING CFD SIMULATIONS The aspect ratio (W/H) of the courtyard influences the indoor air speed values, with the exception of the air speed inside the upstream rooms. A single courtyard with W/H = 0.66 provides higher indoor air speed than a narrow courtyard with W/H = Two consecutive wider courtyards (W/H = 0.66) provide higher indoor air speed than two courtyards of W/H = 0.33 for the central CV rooms. In general the SV rooms have very low indoor air speeds (< 0.1 m/s) while the presence of more than one courtyard can provide significantly better ventilation for the central CV rooms ( m/s). However, this improvement is different among the three floors and almost insignificant for the remaining SV rooms in the two-courtyard building THERMAL COMFORT ANALYSIS For cases with single-side ventilation, ground-floor rooms were always cooler than top rooms, independently of the orientation and shape of the courtyard. The slightly higher air speed of the top-floor SV rooms in comparison with the ground-floor SV rooms seems to be not enough to counteract the influence of the solar radiation on the roof and wall facade for these specific prototypes. On the other hand, the higher air speed values provided by cross-ventilation strategies improve thermal comfort under warm conditions even if the exterior air temperature is quite high, i.e. in the range of 26ºC to 32ºC. For rooms that are more protected from direct and indirect solar radiation, like ground-floor rooms, higher air speed values are not as crucial as for the top-floor rooms if cooking activity is not considered. The best thermal comfort on top-floor rooms is achieved by providing cross ventilation through wider courtyards, by the use of exterior louvers and by orienting the room towards the SSE and NNW. Therefore, with the application of these strategies thermal conditions during the summer improve in terms of PMV from 1.2 to 0.87 and in terms of Effective Temperature (ET*) from 32.4 C to 31 C which is close to the upper limit of Old Havana summer comfort conditions (ET* = 30.6 C) according to Tablada et al. (2009). 4. GENERAL DESIGN RECOMMENDATIONS FOR COURTYARD BUILDINGS In this section a summary of the general recommendations for the design of naturallyventilated courtyard buildings in Old Havana are presented. The recommendations are distilled from the previous studies which included field measurements and thermal sensation survey, CFD simulations and thermal comfort analysis (Tablada et al. 2006, 2009). Figure 3 and 4 illustrate several building layouts for each plot type out of around 200 analysed. Detailed recommendations for each of the three plot types and with several open space ratios will be presented in a future publication. 5

145 Figure 3: Schematic representation of some possible building layouts (out of 160 considered) for plot type 1 (a, b, c) and plot type 2 (d, e, f) with open space ratio = 0.3. The modules in grey represent the courtyard area and the modules with lines represent the rooms with cross ventilation by direct contact with two courtyards or through an adjacent room. Figure 4: Schematic representation of some possible building layouts (out of 32 considered) for plot type 3 with open space ratio = 0.3. The modules in grey represent the courtyard area and the modules with lines represent the rooms with cross ventilation by direct contact with two courtyards or through an adjacent room GENERAL RECOMMENDATIONS 1. Building geometry Open space ratios > 0.25 are recommended. Two types of courtyards are recommended: (1) a wide courtyard (0.6 W/H 1.0) to ensure enough daylight and ventilation inside main rooms (living rooms, dining rooms and bedrooms), to provide some greenery, circulation and access to apartments and (2) narrow courtyards (0.3 W/H 0.5) for services rooms and as a secondary opening for the main rooms to ensure CV. Ventilation shafts may also be a third option to ensure CV if space is limited. An interconnection between the street and the courtyards and among the main courtyards through a circulation path on ground floor is recommended. For plot type 1 and 2 (Fig. 3), buildings with courtyards equivalent to two modules should preferably have less than around 9 m height (1 to 3 floors). For plot type 3 (Fig. 4), buildings with a wide courtyard (W > 6 m) could have a maximum height of 11 m (3-4 floors). If one or two wide courtyards (W 7 m) are linked with the street, the maximum height of the building could be 14 m. 6

146 2. Orientation The orientation of the courtyard s main axis should prioritize the climatic factors (prevailing winds, solar radiation) rather than following the actual plot orientation (e.g. in Figure 3, case c and f, and in Figure 4, case d ). Windows orientation on top-floor rooms should be taken into account according to the function of the room. Daytime rooms like living-rooms should preferably be oriented towards the SSE-NNW. On the contrary, top-floor bedrooms should preferably face ENE for SV cases but for CV cases they should face SSE-NNW in order to avoid solar radiation on the WSW orientation. Kitchens and bathrooms can be oriented to WSW. If oblique courtyard walls and windows are possible, then orientations ranging clockwise from NNW to NNE and from SSE to SSW are preferable. For plot type 1 (Fig. 3), cases a and b are preferable for buildings with ENE and WSW facade orientations. Case c is better for NNW and SSE. For plot type 2 (Fig. 3), case e is preferable for buildings with ENE and WSW facade orientations. Case f is better for NNW and SSE facade orientations. For plot type 3 (Fig. 4), the longest courtyard s facades should preferably be oriented towards NNW and SSE. 3. Ventilation and solar protection Cross ventilation is recommended for the main daytime-use rooms like the living-room and dining-room. Cross ventilation on bedrooms is more effective and necessary on top-floor than on ground and middle-floor bedrooms. A connection between SV rooms by internal openings or by sliding walls is recommended in order to provide cross ventilation when required. Wider courtyards (0.6 W/H 1.0) should have proper sun shadings over windows and courtyard walls (e.g. exterior horizontal louvers or pergolas with wines). The use of movable louvers as part of the window system is recommended for the main rooms on every floor. Sun shadings should protect, at least, the top-floor rooms facing the narrow courtyards (0.3 W/H 0.5). The use of transitional spaces around courtyards like galleries and balconies should be promoted in order to avoid direct solar radiation and brusque changes in radiant temperature and daylight values. 5. CONCLUSIONS In this paper, general design strategies to favour natural ventilation and thermal comfort inside residential buildings in Old Havana have been recommended. The design strategies are based on previous studies in which field measurements, thermal comfort survey, CFD simulations, thermal simulations and a comfort analysis have been conducted for different generic courtyard buildings. The positive effect of the air movement on thermal comfort in warm and humid conditions has been given priority for the elaboration of the recommendations. Higher air speed values provided by cross ventilation strategies improve thermal comfort for the rooms which are more exposed to solar radiation like top-floor rooms and rooms oriented towards ENE and WSW. The cooling sensation of air movement is effective even if the exterior air temperature is in the range of 26º C and 32º C. In the context of Old Havana, three main design strategies should be promoted: (1) to provide cross ventilation in the majority of rooms by means of a sequence of different sizes courtyards linked to the street through a ground-floor circulation path; (2) to use a higher open space ratio than the minimum required by the current urban regulations in 7

147 the Historical Centre, preferably > 0.25 in order to allow wider inner courtyards with 0.6 W/H 1.0; and (3) to provide an efficient solar protection for the wider courtyards including vegetation- in order to reduce the solar heat gain. The results of this and previous studies indicate that adequate design solutions can provide summer indoor thermal conditions within or close to the limits of the comfort zone proposed for Old Havana. The recommendations of this study can be useful for the extension and/or improvement of the current urban regulations of the Historical Centre of Havana. They can also guide the decisions of practitioners working in other compact low-rise urban areas in tropical humid regions. Detailed recommendations for each of the three plot types with a larger number of design options will be presented in a future publication. Further work is needed to evaluate thermal, daylight and energy performance of optimal prototypes for each plot and facade orientation. 6. REFERENCES Bittencourt, L, Peixoto, L.,2001. The influence of different courtyard configurations on natural ventilation through low-rise school buildings. Paper presented at the Seventh International IBPSA Conference. Rio de Janeiro. Cheung, J.O.P., Chun-Ho Liu., CFD simulations of natural ventilation behaviour in highrise buildings in regular and staggered arrangements at various spacings. Energy and Buildings 43, EnergyPlus Energy Simulation Software, DOE Energy Efficiency & Renewable Energy, Building Technology Program, Available from: energy.gov/buildings/energyplus. Fanger, P.O., Toftum, J Extension of the PMV model to non-air-conditioned buildings in warm climates. Energy & Buildings, 34, Fluent Inc Fluent 6.1 User Manual. Givoni, G Climate Considerations in Building and Urban Design. Van Nostrand Reinhold, New York. Koenigsberg O.H., Ingersoll, T.G., Mayhew, A., Szokolay, S.V Manual of Tropical Housing and Building. Longman, London. Lippsmeier, G Building in the Tropics. Callwey, München. Murakami, S., Kato, S., Ooka, R., Shiraishi, Y., Design of a porous-type residential building model with low environmental load in hot and humid Asia. Energy and Buildings, 36, National Office of Statistics (2011). Available from: ]. [Accessed 20 March Ng, E., Designing for Urban Ventilation, In: Ng, E. (ed) Designing High-Density Cities for Social and Environmental Sustainability, Earthscan, London. Office of the City s Historian, Plan de desarrollo integral. Plan Maestro de la Oficina del Historiador, Havana. Rajapaksha, I., Nagai, H. Okumiya, M A ventilated courtyard as a passive cooling strategy in the warm humid tropics. Renewable Energy, 28, Tablada, A, Blocken, B, Carmeliet, J, De Troyer, F, Verschure, H., On natural ventilation and thermal comfort in compact urban environments the Old Havana case. Building and Environment, 44(9), Tablada, A, Blocken, B, Carmeliet, J, De Troyer, F, Verschure, H., Airflow conditions and thermal comfort in naturally-ventilated courtyard buildings in a tropical-humid climate. Paper presented at the 6th International Conference on Urban Climate, Gothenburg, June. Yuan, C., Ng, E., Building porosity for better urban ventilation in high-density cities: A computational parametric study. Building and Environment, 50,

148 NEXT-GENERATION CURTAIN WALLS WITH VACUUM INSULATION PANELS - SUSTAINABILITY AND DESIGN FREEDOM Dr. Mikkel Kragh 1 and Dr. Valerie Hayez 2 High Performance Building Solutions, Dow Corning Europe Steve Zhou 3 High Performance Building Solutions, Dow Corning China 1 Dr. Mikkel Kragh mikkel.kragh@dowcorning.com, Tel: Dr. Valerie Hayez valerie.hayez@dowcorning.com, Tel: Steve Zhou steve.zhou@dowcorning.com, Tel:

149 NEXT-GENERATION CURTAIN WALLS WITH VACUUM INSULATION PANELS - SUSTAINABILITY AND DESIGN FREEDOM Abstract The energy performance of buildings is a key challenge in the context of urbanization and densification of cities. Buildings account for approximately 40 per cent of carbon emissions globally and energy regulations will become stricter in an effort to create more sustainable cities. Future energy regulations will pose a real challenge in terms of building envelope energy performance. Pressure to reduce the energy transmission of curtain walling has brought about a range of technological developments such as glass coatings, thermal breaks and active facades but strict regulations are more than ever being felt in the form of restriction of design freedom. The paper introduces innovative high performance solutions for energy efficient curtain walling. The paper explores the relationship between design and performance. The aim is to gauge the limits of current curtain walling technology and discuss the value of performance enhancements for slim envelopes. The focus is on architectural expression and the freedom to develop geometrically expressive curtain walling for high performance buildings. Slim high performance solutions potentially translate into greater exploitation of building footprint, which is commercially advantageous but also a highly sustainable design element in a dense urban context. The paper provides a critical review, describing the technology as well as the approach to the thermal modeling of the systems. The results are discussed in the context of the commercial building sector in Hong Kong and Greater China with a commentary on applicability for different climate zones. Keywords: Curtain Wall; Façade Design; Thermal Performance; Vacuum Insulation Panel. 1. INTRODUCTION In a time where the energy performance of buildings needs to be addressed not only by visionary designers and clients, but across the board, the challenge is to not sacrifice design freedom and quality architecture. The performance of curtain wall has been enhanced incrementally over the past decades and it is reaching certain limits mainly due to the need for vision area and the inevitable effect of the framing. A step change in insulation performance may quite possibly offer new opportunities for curtain walling in a world of high performance building. The need for improved curtain wall thermal performance and importantly the required reduction of solar gains drives towards the use of higher percentages of opaque area. Classic spandrel strips (Figure 1) may in some instances increase in size and potentially be perceived as undesirable for aesthetic reasons. Therefore, architectural trends evolve towards a broken up elevation layout whereby high performance is delivered through a combination of alternating vision area and insulated parts in a more or less randomized pattern across the elevation (Figure 2). 2

150 Figure 1 Illustration Of Traditional Contemporary Façade Design Figure 2 Illustration Of New Trends In Façade Design, Whereby More Non-Vision Area Is Introduced To Meet The Higher Energy Performance Requirements As the performance requirements call for higher levels of thermal insulation and the architecture for a slimmer building envelope, traditional insulation methods reach their limits and alternative high performance solutions become both necessary and desirable. Dow Corning has developed solutions for integration of Vacuum Insulation Panel (VIP) in curtain walling. The VIP is protected within a sealed unit, providing a robust product which can be handled during assembly and installation. A cross-section of the Architectural Insulation Module (AIM) is illustrated in Figure 3 [1]. Figure 3 Cross-section of the edge of an Architectural Insulation Module (AIM), showing a Vacuum Insulation Panel (VIP) inserted in the cavity of an Insulating Glass Unit (IGU) The technology is that of insulating glazing unit (IGU) with inserts offering enhanced thermal insulation of compact architectural panels. The module facing finish is optional and the module thickness is driven by performance requirements or the solutions offer maximum thermal insulation where a thin envelope is desired or required. Potentially the thermal performance is achieved within the space of a standard glazing unit, which opens up new opportunities for architectural designs. Importantly, the offering is not just the insulation material itself, but a customized finish and performance. Examples of potential finishes are illustrated in Figure 4 and Figure 5. 3

151 Figure 4 Potential Finishes For The External Facing of AIM: Glass Figure 5 Potential Finishes For The External Facing of AIM: Wood 2. FAÇADE DESIGN The following sections describe a series of façade layouts as well as the various parts of the curtain wall solutions (framing, vision area glazing and spandrels) defined as a basis for benchmarking of overall façade thermal performance. 2.1 CURTAIN WALL LAYOUT As explained in the introduction, spandrels in new façade designs trend to differ from the traditional strip layout and evolve towards designs with multiple strips of spandrel or without vision area, as illustrated in Figure 6. Figure 6: Examples Of Various Elevation Design To Achieve WWR Requirement In this study, to simplify the process we have used the classic elevation façade design (strip vision and strip opaque). There are three options (Figure 7) with different WWR (70%, 55% and 40%) by playing on the heights of vision and spandrel. Figure 7: Elevation Designs Adopted For Study Window To Wall Ratio (WWR) From Left To Right: 70%, 55%, 40% 4

152 2.2 FRAMING This paper focuses on a typical example of a unitized curtain wall framing system which is a four-side structurally glazed system with no exterior vertical or horizontal capping. The systems presented in this paper should only be seen as examples. The reference solutions with conventional thermal insulation are modeled to the limit of their performance for the given curtain wall system depth. The available space between the framing members is assumed filled to the back of the profiles. 2.3 VISION AREA GLAZING The double insulating glass unit build-up is modeled as 6mm external low-e coated glass, a cavity of 12mm filled with a 90% argon-air mix, and an internal 6mm glass (see Table 1). The IGU centre-of-glass thermal performance (Ug) was determined by means of WINDOW 5.2 software (by LBNL, certified by National Fenestration Rating Council, NFRC). Table 1: Vision Area Glazing Used For Modeling Configuration Ug (W/m 2 K) 6 Double Silver Low-E + 12Ar SPANDREL Two types of spandrel conditions, Shadow Box (S1, S2, S3, S4) and Opaque (S5, S6) have been considered. Six methods (Table 2) of insulating spandrel were evaluated. S1 has a 50mm RW, which is considered as a most common spandrel configuration for buildings in China. S2, S3, S5 have very thick RW, which are more likely considered for the high performance buildings, such as green or sustainable buildings. S4 and S6 use AIM solutions. Spandrel No. S1 Table 2: Spandrel Types Used For Modeling Configuration 6 Reflective Coating+2mm Aluminum Backpan +50mm RW Remark Shadow Box (Monolithic Glass) S2 S3 S4 S5 S6 6 Reflective Coating+2mm Aluminum Backpan +150mm RW 6 Double Low-E+12a+6+2mm Aluminum Backpan +130mm RW 6 Double Low-E+16a+6 Ceramic Paint +16a (15mm VIP) +6+2mm Aluminum Backpan +100mm RW 6 Ceramic Paint+2mm Aluminum Backpan +150mm RW 6 Ceramic Paint +16a (15mm VIP) +6+2mm Aluminum Backpan +100mm RW Shadow Box (Monolithic Glass) Shadow Box (IGU) Shadow Box (AIM) Opaque Spandrel (Monolithic Glass) Opaque Spandrel (AIM) 5

153 The details of conventional insulation for stack joint are illustrated in Figure Figure 8: Spandrel S1 (RW is shown in brown color) Figure 9: Spandrel S2 (RW is shown in brown color) Figure 10: Spandrel S3 (RW is shown in brown color) Figure 11: Spandrel S5 (RW is shown in brown color) Figure 12 and 13 illustrate the integration of AIM for stack joint. Figure 12: Spandrel S4 (RW is shown in brown color, and AIM is shown in pink color) Figure 13: Spandrel S6 (RW is shown in brown color, and AIM is shown in pink color) 3. MODELLING CURTAIN WALL THERMAL PERFORMANCE The method used to calculate the overall façade U-value refers to ISO 10077[3] and JGJ/T [4]. This method takes into account the individual U-value of a component (frame, centre-of-panel, centre-of-glass, and edge) and the corresponding transmission area. The following equation is used: U facade = ( U i A i ) ( A i ) (EQ01) Where, U i is the component U-value; A i is the area of the component; A i is the total transmission area. WINDOW and THERM software (by LBNL, certified by National Fenestration Rating Council, NFRC) models two-dimensional heat transfer effects through the glazing systems based on the finite element method, and are used to generate centre-of-glass, 6

154 frame and edge U value for the components of curtain wall systems. Additionally, THERM can help to predict localized surface temperature for the components. 4. RESULTS Project-specific thermal modeling will be required in connection with building projects, and timely specialist advice is likely essential in order to assess achievable façade performance at the early stages of design. The results presented in this paper are based on a number of assumptions and serve to illustrate aspects pertaining to curtain wall detailing and the performance of alternative insulation solutions. 4.1 OVERALL FAÇADE THERMAL PERFORMANCE Following the modeling approach and area weighted calculation method described, façade U-values were determined for different elevations mentioned above. The main results for each elevation are set out in Table 3. Table 3: U-Value For Overall Façade System Combinations of Vision And Spandrel Vision + S1 (Monolithic Glass, 50mm RW) WWR 70% Overall Facade U-Value (W/m 2 K) WWR 55% WWR 40% Vision+Shadow Box (Conventional) Vision+Shadow Box (AIM) Vision+Opaque (Conventional) Vision+Opaque (AIM) Vision + S2 (Monolithic Glass, 150mm RW) Vision + S3 (IGU, 130mm RW) Vision + S4 (Shadow Box AIM, 15mm VIP, 100mm RW) Vision + S5 (Monolithic Glass, 150mm RW) Vision + S6 (AIM, 15mm VIP, 100mm RW) For each of the considered façade elevations, there is benefit in replacing RW with AIM as the overall U-value for façade decreases by 5% to 14%, depending on the vision area percentage. The higher the percentage of spandrel, the lower the U-value for the façade becomes. It should be noted that the U value requirement becomes more and more stringent all over the world. Hong Kong, since use OTTV regulation, the U value requirement varies from project to project. From experience, the average U value requirement for overall façade is 1.8~2.0 W/m 2 K. Shanghai required for 2.0 W/m 2 K maximum in the past, but it recently asks for 1.8 W/m 2 K maximum. Beijing requires for 1.6 W/m 2 K maximum now. Compared with the results from Table 3, most of the spandrel configurations won t be able to meet the more and more stringent U value requirement. As restricted by the limited space within the frames, increasing the thickness of conventional insulation will not be efficient enough to meet the overall U value for the near-future buildings, 7

155 however, improving the thermal break level of frame, reducing the WWR, and using high performance insulation could be considered as the solutions for China. 4.2 CONDENSATION RISK In order to evaluate the condensation risk, the THERM software was used to determine the temperature at the internal intersection between vision area and frame. CWCT guidelines for environmental conditions were followed (winter outdoor -5 o C ambient temperature; indoor +20 o C ambient temperature) [5]. Figure shows the isotherms of stack joints with conventional insulation and AIM. The figures also indicate the minimum internal surface temperatures. A summary is provided in Table 4 for the different system types and insulation solutions. Figure 14: Vision+Shadow Box (IGU) Figure 16: Vision+Shadow Box/ Opaque (Monolithic Glass) Figure 15: Vision+Shadow Box (AIM) Figure 17: Vision+Opaque (AIM) Table 4: Condensation Risk - Minimum Internal Surface Temperature Combinations of Vision And Spandrel Vision+Shadow Box (Monolithic Glass) (Conventional) Vision+Shadow Box (IGU) (Conventional) Vision+Shadow Box (AIM) Vision+Opaque (Conventional) Vision+Opaque (AIM) Minimum Internal Surface Temperature ( o C) Stack Joint Intermediate Transom

156 These results show that the minimum internal surface temperatures of all the systems stays above +6 o C dew-point temperature to avoid condensation (for a typical office with 40% RH and +20 o C ambient temperature). However, in comparison to conventional insulations, the AIM solutions have higher internal surface temperatures in general. This could be valuable to some cities with high relative humidity environment, such as Hong Kong and Shanghai, as the AIM solutions tolerate higher relative humidity without condensation. 5. CONCLUSIONS The thermal performance of curtain wall systems with novel architectural insulation module (AIM) was compared with that of conventional rock wool solutions. The study is based on a typical four-side structurally glazed unitized curtain wall system. The benchmark of thermal insulation is the conventional rock wool insulation. The paper shows that novel architectural insulation module can enhance the performance of typical curtain wall systems, compared with conventional insulation solutions. The solutions are compared in terms of condensation risk and it is shown that the novel designs reduce the risk compared with the conventional curtain wall systems. The AIM solutions also offer building designers with freedom to design higher WWR for curtain walls compared with conventional solutions. An important aspect in terms of benchmarking is that the rock wool insulation is well filling the space within the spandrel panel with no gap. It is unlikely this will be achieved in practice and further work is required to establish as built performance of common spandrel details. This is in stark contrast to the novel architectural modules. These solutions will not be as dependent on workmanship, and it is therefore believed that the models represent what is actually delivered by modules fabricated in a controlled environment. REFERENCES [1] Dow Corning website [online]. Available From: [Accessed 12 July 2013]. [2] Tenpierik, M Vacuum Insulation Panels Applied in Building Constructions. PhD Dissertation. Delft Technical University. The Netherlands. [3] ISO Thermal Performance Of Windows, Doors And Shutters-Calculation Of Thermal Transmittance-Part 1: Simplified Method. [4] JGJ/T Calculation Specification For Thermal Performance Of Window, Doors And Glass Curtain-Walls. China. [5] CWCT. Standard For Systemized Building Envelopes, Part 5. Centre For Window And Cladding Technology. United Kingdom. 9

157 HONG KONG DESIGN INSTITUTE A MODEL OF URBAN DENSITY AND SUSTAINABILITY Thomas Coldefy, Isabel Van Haute and Maxime Pruvost COLDEFY & ASSOCIES ARCHITECTES URBANISTES, France 94, rue de wazemmes LILLE tcoldefy@caau.fr ivanhaute@caau.fr mpruvost@caau.fr 1

158 ABSTRACT In this abstract we are introducing Hong Kong Design Institute as an example of sustainability in dense urban environment for its features and design: How can a place on the one hand fulfil an ambition for synergy, aiming to harmonise the channels linked to design and on the other hand express the identity of each specialty? How can it open itself up to the outside world whilst still retaining the exclusivity and intellectual protection required to produce the best design? How can we construct a building for a trendsetting institution, without at the same time linking it to a category? To do so, the institute must offer an infrastructure capable of producing design and of connecting it to the outside world. The white sheet, the starting point of everything symbolises the new Hong Kong Design Institute. The raising of the Institute enabled the base to be transformed into a large public space for interaction and the exchange of ideas, an urban space of which the key role is to encourage meetings and relaxation and to provide a natural green space. Therefore connectivity to the city appears virtually natural. The pillars of education are incorporated in the complex. They accommodate the classrooms and support the institute. They join together to merge into the aerial city that provides services and quieter places. In this way, the Design Institute includes the operational components between the sky and the ground, a complex that is typical of Hong Kong. Keywords: Connection, Design, Landscape, Multifunctional, Natural, 2

159 1. PROCESS Thorough analysis of the surroundings shows a typical Hong Kong environment, assembling a mass of people in the podiums, filled with transportation, retail, restaurants and other leisure activities, while when ascending in the residential towers, isolation comes in. This analysis resulted into a decomposition of programmatic elements as architectural components such as vertical towers and horizontal spaces engaging with the public and landscaped spaces, a shared space connecting functions and a diagonal connector expressing mobility while experiencing the different levels of the building. Those components are a reinterpretation of the city within the city, a place for interaction For the Hong Kong Design Institute design, COLDEFY & ASSOCIES ARCHITECTES URBANISTES wanted to respond to this contradictory situation by lifting a part of the program in the air in order to create public spaces on the ground floor where students and community can exchange; all functions of the podium are for the students and open to public; galleries, cafes, bookshops, auditoriums, sport facilities and a public garden on top. COLDEFY & ASSOCIES ARCHITECTES URBANISTES process strives to express the legibility of a building for user appropriation to the architecture identity This way the library, common to the different design departments, forms a platform for symbioses between all students. The four towers house the different design departments and form the legs of education holding up the world of ideas The COLDEFY & ASSOCIES ARCHITECTES URBANISTES team contrived to make the Hong Kong Design Institute building what we call a metaphor with the four towers supporting a blank sheet on which creativity is about to burst forth. With the four departments of Hong Kong Design Institute occupying the towers, the blank sheet is also seen as a field in which the seeds of new design can be sown. The lifted program sustained by the four towers is an invitation to utilize public space and provoke creative emulations. 3

160 2. CONNECTING WITH THE PUBLIC With these considerations in mind, the ground floor plaza serves as semi-public space for events and is accessible to the community at large; on top of that the campus facilities such as swimming pool & basketball courts are open to the public. Facilities such as the art gallery on ground floor, one of the largest in Hong Kong, are also connecting the communities to the creative activities of the Hong Kong design institute. Facilities for the public such as basketball court & swimming pool 3. FLEXIBILITY OF SPACE The exhibition hall s open plan is also adaptable for different events, all public spaces are multi-functional, and serves as exhibition spaces, leisure sitting areas and informal performances spaces. All (class)rooms, situated in the towers, are column free these spaces are open areas that can be filled in, divided or organized as needed. The roof garden on the 9 th floor serves as an outdoor activity space for the users of the building, students use the roof for multiple uses, and the place is suitable for organizing events. This flexibility of all facilities allows more room to engage the public and the student in using and interacting with the different public spaces. 4

161 4. SITE RESPONSIVE PLANNING The building is well connected to all facilities adjacent to the site such as MTR, leisure and recreational area and bus terminal. There are also connections within the site with the escalator from ground floor to 7 th floor, the elevated landscape deck links up the 4 towers for towers containing the four design departments. The building is also linked with bridges between Hong Kong Design Institute & the Lee Wai Lee building. One of the main goals was also to connect the site and the neighbourhood at ground floor open plaza by means of the internal street, the design boulevard, that is open to all public and students, inviting all to come and see the campus activities 5. EFFECTIVE CIRCULATION DESIGN CONSIDERATION FOR HIGH RISE CAMPUS In such a dense environment circulation design is crucial in connecting the program effectively to the neighbourhood and all surrounding facilities. The escalator landings from ground floor to 7 th floor, transfer students effectively from entrance to the strategic communal spaces and Learning Resources centre. The circulation design also features: - Lift landing are designed to distribute students at strategic learning space/floor. - Motions sensor for are installed for escalators (energy saving control) - Wind sensor for escalators (escalators will automatically stop operation during strong wind situation) 6. TREE PRESERVATION AND LANDSCAPE DESIGN Offsite tree transplanting at construction stage has helped preserving existing trees New tree planting at podium garden and street level green area also increased the green ratio of the project. Extensive green slope are facing communities around the building. Roof garden at 9 th floor also serves as outdoor activity space and green roof at the top of the towers to enhance urban greenery and thermal performances of the roof. Green Street 2/F 2/F Ground Roof 9/F 5 Second 9/F Roof

162 7. NATURAL LIGHTING Skylights introduce natural light into interior of the plaza and provide light for all activities. Low emission glass wall allow natural light into the sky platform and yet controls heat gain and glare. Grey tinted and low emission glass reduces heat gain and Air conditioned cooling load, each towers also has a void around it passing through the platform which allows natural light to be spread all around. Glass Wall allows plenty of natural lighting into interior Skylight allows natural light to penetrate to G/F plaza Glass Wall along periphery of 4 towers and sky platform Tinted glass at Lee Wai Lee Building 35% fritted pattern of Low -e glass was adopted at Hong Kong Design Institute to optimize the natural day light penetration 6

163 CONCLUSION: The building, which has brought under one roof different design departments formerly spread throughout Hong Kong, provides the community with a meeting place by making its auditoriums and sports facilities available for public use. It also brings new energy to the social life of the area with the presence of students on the campus as well as the numerous exhibitions and activities organized around the new urban spaces that have been created. The project offers a spatial re-interpretation of the built-up city context by allowing social interaction on different levels and creating new connections with the ground. Sustainable construction is not only about high technology and costly solutions. All the features of the building; the flexibility of space and connection of the building to the public for people to appropriate the space and use it in different ways according to the time is a perfect example of a building ability to integrate the territory on the long run. Making the building a key element of the life of the district and ensuring its long term sustainability in a dense urban environment by saving land, energy and resources. 7

164 SUSTAINABLE PUBLIC HOUSING DESIGN IN A SMALL COMPACT SITE (REDEVELOPMENT OF EX-YUEN LONG ESTATE) Ken K.S. CHEUNG 1 and Chimmy W.M. CHU Hong Kong Housing Authority, Hong Kong 1 ken.cheung@housingauthority.gov.hk, Tel: (852) , Fax: (852)

165 SUSTAINABLE PUBLIC HOUSING DESIGN IN A SMALL COMPACT SITE (REDEVELOPMENT OF EX-YUEN LONG ESTATE) ABSTRACT Located at the north of Yuen Long Town Centre, the Public Rental Housing development at the reduced site for Ex-Yuen Long Estate shall provide 438 flats in late The small elongated site is about 0.43 hectare, bounded by heavily trafficked roads on three sides. Apart from the emission impact from the adjacent factory buildings, the site layout is subject to the notable nuisance due to the elevated MTR viaduct of Long Ping Station. Apart from the environmental constraints like many residential developments in the urban area, the site is also lack of open space and subject to complex geotechnical constraints. It lies within both the Scheduled Area No. 2 (North West New Territories) and Scheduled Area No. 3 (Railway protection areas). Ground Investigation information reveals that the site is underlain by interbedded layers of hard and soft materials from approximately 20m-130m deep. Embracing with a caring attitude to foster social and environmental sustainability, the low carbon building design aims to create a green, cost effective and healthy living environment in a small compact development. The paper shall highlight some key features essential to the design and construction processes in order to achieve the highest rating for the two Green Building Design Label systems, namely the Beam Plus version 1.2 on passive design for residential development and a Design Label of the China Green Building Label (CGBL). It is an exemplary demonstration for sustainable public housing design in a high density urban living environment attributive to the balanced use of green technologies. Keywords: Hong Kong Housing Authority; HA; Sustainable public housing; Beam Plus version 1.2; passive design. 1. BACKGROUND OF THE PROJECT In February 2010, the Government announced that 75% of the former Yuen Long Estate site (western portion) would be used for private residential development to increase the supply of small and medium-sized flats 2, while the remaining 25% (eastern portion) would be returned to the Hong Kong Housing Authority for a public rental housing development (herein Ex-Yuen 2 The land sale tender of the private housing site, known as Yuen Long Town Lot No. 518, was launched on 31 December

166 Long Estate or the Project ). The Project is located at the north of Yuen Long Town Centre, on a narrow and flat site of about 0.43 hectare. The Tung Tau Industrial Area is located to its further north which is linked to the Site via a footbridge crossing Yuen Long On Lok Road. Existing infrastructure including mainstream transport facilities of MTR Long Ping Station and Light Rail Stations, schooling, community facilities and basic amenities are provided within 500m walking distance from the Site. The Site was zoned as Residential (Group A) ( R(A) ) on the Approved Yuen Long Outline Zoning Plan No. S/YL/18. The Project comprises two site specific domestic blocks, providing 438 flats and about 400m 2 retail space at ground level facing the local shopping street of On Ning Road. Piling works has been commenced in February 2013 with the anticipated completion of the whole development by end THE DESIGN CONCEPT PASSIVE APPROACH The design has been optimized taking into account of the development potential and various site constraints inherent to engineering and environmental considerations in the following paragraphs. 2.1 Site Constraints The Site has severe geotechnical and noise constraints. In the first place, the small and narrow Site already limits the planning for recreational and open space at ground level. This is aggravated by the building height restriction, the need for set back facing Yuen Long On Ning Road to the south as well as the non-noise sensitive design facing West Rail to the north. Major considerations put forth in the planning and design of the Project are summarised in the following paragraphs Geotechnical, Foundation and Structural Considerations The Site lies within both the Scheduled Area No. 2 (NW New Territories) and Scheduled Area No.3 (MTRC Railway), requirements for Ground 3

167 Investigation (GI) and foundation works in Scheduled Areas are to be followed. The Site is underlain by thick layers of completely to highly decomposed meta-siltstone interbedded with soft materials from 20m to more than 130m deep. Bedrock of impure marble (with cavities and cavity infill) is located generally at 130m to more than 160m deep. The bedrock cannot be reached with drillholes sunk more than 180m deep at northern part of the Site. The disposition of buildings has been carefully manipulated to minimize the encroachment in the deep cavities. In view of the constraints, a special pile type namely, Shaft Grouted Barrette is adopted to underpin the two blocks. The use of Shaft Grouted Barrette, with estimated average pile length of about 65m, is comparatively more effective in both economical and technical terms than other foundation systems. As a result, the foundation works could reduce the overall concrete volume by about 21,000 m 3, and hence likewise the equal amount of excavated waste. 2.2 Environmental Considerations Two site specific blocks, of 18 storeys and 29 storeys with building height difference of about 30m, are proposed with single-aspect design at the noise prone fenestration of blocks to mitigate severe traffic noise and railway noise. Other environmental factors are elaborated below Air Quality and Ventilation Environmental Assessment Study was conducted at early stage to verify that emission from vehicular traffic and industrial buildings chimneys is within relevant air quality criteria and would not pose unacceptable air quality impact on the Project. An Air Ventilation Assessment (AVA) was undertaken to identify the potential air ventilation problems associated with the Project and to decide on the optimized design solution. The AVA by Computer Fluid 4

168 Dynamics simulations indicated that the design of twin towers with substantial stepping height, increase of the width of building separation and modified building configurations would induce slight improvement to air ventilation at pedestrian level as compared to a based scheme with two identical buildings of same height. Also, to maintain building permeability for penetration of prevailing wind and air ventilation, a minimum 20m wide separation is provided between the two blocks and a 6.5m non-building zone 3.along the west boundary. An overall 43.3% permeability at the low zone is achieved, which is far exceeding the requirement of 33% minimum under SBDG 4 in the Buildings Regulation Noise Assessment The Site is subject to severe traffic noise from the adjoining On Ning Road and On Lok Road, railway noise from West Rail to the north and industrial noise from industrial buildings to the east. According to the previous West Rail Environmental Impact Assessment report, a setback of 35m from nearest railway track to any planned Noise Sensitive Receivers was recommended in order to meet the acceptable noise criteria. An EAS has also been undertaken to examine the feasibility of the proposed public housing development in terms of environmental considerations. Integrated layout of defensible building design (i.e. single-aspect block), use of podium structure, noise barrier and architectural fin as shielding are put in place as effective and passive noise mitigation. As a result, full compliance rate for road traffic noise, and the noise from the West Rail could be achieved, whilst those induced by the industrial buildings will be within the noise criteria Micro-climate Studies Like many other public housing projects, we have conducted environmental studies to refine the block design. The studies covered the wind environment, 3 According to the AVA report, the 6.5m separation is measured 1.5m building setback of the public housing blocks to the site boundary. Reference : 4 Sustainable Building Design Guides issued by the Buildings Department, the Government of HKSAR. 5

169 outdoor thermal comfort and sun shadowing analysis at podium level, as well as indoor environmental quality of flats for each building tower. The Vertical Daylight Factor (VDF) indicated that all the flats satisfied the required 8% of habitable room and 4% of kitchen respectively. Further VDF simulation also showed that over 12% VDF at the façades of the lowest floors of neighbouring sensitive receivers surrounding the Site could be maintained. The calculated ventilation rate for all the flats are well above the requirement as stipulated in the PNAP-APP The typical lobby and common corridors are naturally ventilated to satisfy the requirement of 1.5 ACH Thermal facade analysis Calculation of thermal transfer value by method of OTTV shows the ESE and Sothern facades of Block 1 and the WNW, WSW and Southern facades of Block 2 will have relatively larger thermal transfer value as compared to other facades. However, due to the assumptions and limitation of OTTV calculation 6, a more sophisticated thermal dynamic modelling has been carried out and the total average weighted thermal transfer value is about W/m 2 7, meeting with the prescribed standards. 3. SUSTAINABLE PLANNING ACTIVE SYSTEM The above passive design strategies enhance the building performance and bring comfort to the residents in a cost effective manner. Other mindful planning and active systems are adopted to foster a more sustainable and healthy living environment. These are 3.1 Landscape strategy An overall greening coverage of 31% of Gross Site Area (GSA) in which more than 10% shall be provided at-grade level in this small and compact Site. A terrace garden is designed at level 5 of Block 2 for the leisure assembly of the residents as well as a supplementary green pocket in the dense urban habitat. The 10m building setback zone along On Ning Road shall be treated with patterned greening to enliven the street ambience.. Extensive greenings are also provided at the podium structure and the main roof of the low block. The 6m high noise barrier on the podium of Block 2 facing On Ning Road will be integrated with vertical greening. The sustainable use of native species and pest-resistance plants are provided to moderate irrigation water consumption after the establishment period. 5 Buildings Department, Practice Note for Authorized Persons, Registered Structural Engineers and Registered Geotechnical Engineers APP-130 issued by Buildings Department, HKSAR. Reference : 6 Calculation of the Overall Thermal Transfer Value for the building under the Hong Kong OTTV requirements issued by Building Department, HKSAR. 7 According to the BEAM Plus version 1.2 issued by HKCGB in 2012, a total of 4 credits can be achieved under the EU 1b, i.e. when 22.0 W/m2 OTTV < 24.0 W/m2.. 6

170 3.2 Use of Materials The Project adopts modular and standardized components in building design with over 50% prefabricated building elements including facades, staircases, slabs and partition walls, which is a challenge for effective construction management for a small development site. At least 50% of timber products from sustainable source for project use are specified. The A/C unit for the Estate Management Office was specified with use of refrigerant having the value less than the threshold of the combined contribution to ozone depletion and global warming potential. Not least, use of products in the building fabric and services that avoids the use of ozone depleting substances was specified. Over 60% of concrete was estimated to be manufactured within 800km from the site. 3.3 Renewable Energy, Energy Efficiency and Saving Measures The following sustainable initiatives are provided in the Project a) Grid connected photovoltaic system is provided on the top roof and roof on machine room floor of Block 2, generating about 2.5% energy for the Project. b) Two-level lighting design in the common areas will enable high efficiency lighting and saving in electricity. A minimum lighting level 8 for safety and security considerations will be maintained around the clock. Installation of manual switch integrated with the door phone handset in each domestic flat as well as their provision at strategic positions at the lift lobby and corridors will enable the required illumination level to 85 lux. c) Rain Water Harvesting System is provided for the Project. The system is estimated to achieve about 38% of annual irrigation water saving. Rain water will be collected from the roof of residential blocks, sterilised for reuse in irrigation of the planter at grade and podium. Where automatic irrigation is not feasible for technical or security reasons, lockable water points will be provided to allow for manual watering. d) Further to preventing evaporation loss, Root Zone irrigation system which will direct supply water from the root to the plant, can achieve a maximum of 70% irrigation water saving. e) In the twin-tank system, the water tank is divided into two compartments. The system adopts an alternative operating approach ensuring continual water supply to tenants when one of compartments is being cleaned. Less 8 30 lux for typical corridors and staircases and 50 lux for typical lobbies. 7

171 water wastage is assured under well-planned cleansing cycle for all the major water tanks. 3.4 HKHA Specifications In 2011, HKHA enhanced the Specification to enable all new HA projects would be Beam plus-ready with Gold rating. In this Project, we will also include the following contract conditions like requiring both the foundation and building contracts to submit waste management and environmental management plans 9, mandatory provision of water recycling facilities to recycle waste water for wheel washing & duct suppression, hard paved construction to achieve clean and safe site environment and proper material storage area hence minimizing handling wastage. Moreover, provision of weighbridge to check the performance of dump trucks leaving the Site will be provided and measures are taken to monitor use of used or well-managed timber for temporary works on site. 4. GREEN LABEL CERTIFICATIONS The Project team submitted the building performance assessment under the BEAM Plus Version 1.2 in August The Project has been independently assessed by BEAM Society Limited and endorsed by the Technical Review Committee as Provisional Platinum rating in March Moreover, the Project has also completed the building performance assessment under the China Green Building Evaluation Label and has achieved the highest 3-Star rating under its Design Label in May CONCLUSION We believe a people-centric approach, caring for people and environment for a sustainable future. Hence, we always adopt a passive design approach from the early inception and planning, optimizing the building performance through conscious site planning, disposition of blocks and configuration of the buildings. After exploring the site potential, we apply technologies by means of renewable energy, boost energy efficiency to create comfort in a sensible manner. As a balanced strategy to strive for sustainable development, we only consider using more efficient mechanical system after exhausting the passive approach as the alternative resources for energy saving. 6. REFERENCES 1) Fung, Ada et al, Planning, Design, and Delivery of Quality Public Housing in the New Millennium. 2) Fung, Ada. Talk on First Platinum Project under BEAM Plus version 1.2 Redevelopment of Ex-Yuen Long Estate, The Hong Kong Housing Authority at HKGBC on 14 June An Environmental Management Plan shall include Environmental Monitoring and Auditing, provision of adequate mitigation measures for construction noise, dust and waste (water discharge etc.) as recommended by the Environmental Protection Department and demonstrating compliance with the air quality management guidelines as detailed in the Environmental Monitoring and Audit Manual (EM&A Manual). 8

172 HOMES IN THE PARK A SUSTAINABLE PUBLIC HOUSING ESTATE CONSERVED FROM AN OLD AIRPORT AT KAI TAK IN HONG KONG Mr. Stephen Yim 1 Chief Architect, Hong Kong Housing Authority 1 Corresponding Author stephen.yim@housingauthority.gov.hk, Tel: (852) , Fax: (852)

173 HOMES IN THE PARK A SUSTAINABLE PUBLIC HOUSING ESTATE CONSERVED FROM AN OLD AIRPORT AT KAI TAK IN HONG KONG ABSTRACT The Hong Kong Housing Authority (HKHA), being one of the biggest public sector developers and flat owners in the Hong, is committed to green design and reducing carbon emission. The public rental housing developments at the Kai Tak Airport comprise Sites 1A and 1B. The two development projects involve the construction of 15 high-rise domestic blocks providing over 13,300 flats for about 34,000 residents. HKHA has adopted the theme of Homes in the Park with supporting Heritage Trail and Neighbourhood Gardens to harmonize and echo with the entire Kai Tak development. The design is people-oriented, functional and costeffective. We developed a Carbon Emission Estimation (CEE) Model to gauge the holistic carbon emission of newly designed public rental housing developments. The model focuses the major aspects of construction, building operation and demolition which have implications for carbon emission, reduction and absorption during the whole building life cycle of 100 years. We also conserved site excavated marine mud into recycled backfilling and paving materials, and adopted new initiatives such as electric vehicle charging facilities, lift regenerative power installations, district cooling system, rainwater harvesting cum root zone irrigation system and fully fitted volumetric precast kitchens and bathrooms etc. Keywords: Public Rental Housing, Homes in the Park, Carbon Emission Estimation 1. INTRODUCTION Being part of the old Airport at Kai Tak, the public rental housing (PRH) developments at Kai Tak Site 1A (3.47 hectares) and Site 1B (5.7 hectares) have distinguished historical background on the aviation development of Hong Kong. Imageries of low flying airplanes over the Kowloon City and the old airport at Kai Tak have become the collective memories of the people of Hong Kong. The two PRH developments provide about flats for residents in 15 domestic blocks, and ancillary retail facilities including a wet market, car parking facilities, kindergartens, neighbourhood elderly centre, integrated children and youth centre and recreational facilities. The construction works started at the end of 2009 with completion scheduled in end Schools and public parks are planned within the vicinity of the developments. 2. BACKGROUND OF KAI TAK DEVELOPMENT The old Kai Tak Airport was an icon of Hong Kong for 77 years before its closure on 6 July After several rounds of public consultation and with the guidance of the Town Planning Board, the statutory Kai Tak Outline Zoning Plan (Kai Tak OZP) was formulated. Kai Tak Development (Figure 1) is a huge and highly complex development project spanning over 320 hectares with the largest available land fronting Victoria Harbour. If offers opportunities to bring the harbour to the people, provide quality living 1

174 environment for around residents, and revitalise the surrounding districts such as Kowloon City, Wong Tai Sin and Kwun Tong. It embraces sustainability and cultivates a comprehensive network of parks and gardens for the enjoyment by all. Figure 1: Master Layout Plan for Kai Tak Development 3. HOMES IN THE PARK We adopted the design theme of Homes in the Park in the two PRH developments, with supporting Park Centre and Neighbourhood Gardens to harmonize and echo with the overall park-like concept of the entire Kai Tak development. The design provides clearly identifiable gateways and connects the estate with existing urban fabric. The idea of Park Centre idea is to achieve complete segregation of vehicular and pedestrian traffic. The central open space is designed as a Park, with tree-lined paths leading from the west entrance plaza and east entrance plaza. These plazas are linked with intimate Neighbourhood Gardens next to the domestic blocks. It encourages social interaction among the residents and enhances the sense of local community. Master layout and rendering of the PRH developments are shown in Figure 2 and 3. 2

175 Figure 2: Master Layout Plan for Kai Tak Site 1A and Site 1B Figure 3: Rendering for Kai Tak Site 1A and 1B The green features of the PRH developments include - passive design heritage environment green initiatives green construction techniques 3.1. PASSIVE DESIGN In refining the estate layout and building design for green and healthy living, we adopted passive building design approach, through air ventilation assessment and micro-climate studies, to optimize the planning and design of buildings and open spaces. This provides healthy and quality living environment for tenants through optimal use of the natural environment such as wind environment, ventilation, daylight and solar radiation as well as energy consumption. We configured and orientated the domestic blocks to capture the prevailing southeasterly wind to maximize natural ventilation; and we designed floor layout to secure good air circulation with ample natural light penetrating into the buildings, including 3

176 both semi-private areas at lift lobbies and corridors, and the private domain in each domestic flat. We bring life to the street level by providing retail facilities primarily in the form of street front shops in pedestrian precincts. The arcades on the first floor are designed to be naturally ventilated to provide an open and welcoming atmosphere while reducing the use of air-conditioning as far as possible HERITAGE ENVIRONMENT We design a central park integrating with the local open spaces of the public rental housing estates. A Heritage Trail, leading from the West Entrance Plaza, meanders through the park, offering interesting and different visual experiences along the trail. The central position of the Park is the Exhibition Gallery including Time line Exhibition, Centennial Wall & Heritage Court as a permanent exhibition Years of Kai Tak. The heritage features include - Time Line Exhibition - 6 milestone years before 1920, 1920, 1940, 1960, 1980, and after 2000 Centennial Wall - symbolically representing the back-drop to the first Kai Tak aircraft runway built during the Second World War Heritage Court - the Centre Piece and Feature of the permanent Kai Tak Historical and Cultural Exhibition to showcase recollections and unique memories of Kai Tak to enhance a sense of belonging amongst the residents Aviation elements such as the Signal Hill and runway axis were adopted and we incorporated a specially designed aircraft icon in landscaping, graphic design and signage. Figure 4: Central Park 4

177 Signal Hill 信號山 Aircraft Icon 飛機標誌 Exhibition Gallery 展覽廊 Figure 5: Aviation Heritage 3.3. GREEN INITIATIVES Throughout the estate, we put in place green design features to reduce environmental impact. Major features include DISTRICT COOLING SYSTEM We have adopted the centralized and energy-efficient chilled water supply system implemented by the Electrical and Mechanical Services Department to provide chilled water to the air-conditioning systems of the non-domestic facilities such as retail facilities, kindergarten and estate management offices. Figure 6: District Cooling System ELECTRIC VEHICLE CHARGING FACILITIES We provide conduit and cable containment to all of the car parking spaces and wiring up to 30% of car parking spaces in the car parks to enable electric vehicle charging, in anticipation of a wider use of electric vehicles in future. 5

178 Figure 7: Charging Facilities for Electric Vehicles LIFT REGENERATIVE POWER A lift motor can work as a generator to produce electrical energy if it operates under heavy load down, light load up or braking conditions. By deploying the latest technology in the lift systems for domestic blocks, we feed regenerated power into the power supply system for use after conditioning by a state-of-the-art regenerative power technology, so as to achieve electricity savings. Figure 8: Lift Regenerative Power RAINWATER HARVESTING CUM ROOT ZONE IRRIGATION SYSTEM We earmarked a portion of the planting area to implement a rainwater harvesting cum root zone irrigation system. The former helps to reduce fresh water consumption by providing filtered rainwater for irrigation while the latter makes use of a mat laid under the soil to store and supply water directly to the plant roots where it is needed most. Evaporation of water can thus be minimized and the amount of irrigation water can be reduced. 6

179 Figure 9: Rootzone Irrigation System 3.4. GREEN CONSTRUCTION TECHNIQUES We are collaborating with contractors and stakeholders in the industry to explore and implement green construction to enhance productivity and efficiency, as well as reducing environmental impact to the neighbourhood MARINE MUD CEMENT-STABILIZATION METHOD FOR BACKFILLING The site was reclaimed from foreshore of Kowloon Bay in the early 1920s that the marine mud on the seabed was not dredged away during the reclamation works in those years. Approximately 15,000 cubic meters of marine mud waste are generated in the excavations for the construction works. The normal practice in the construction industry of disposing the marine mud to either landfills or marine dumping sites is very harmful to the environment. Housing Department (HD) has developed a practical and cost-effective green treatment technology to make use of the original waste and reform it to useful building materials namely Marine Mud Made Materials (MMMM). The technology is well received by the industry 2 as another sustainable solution that resolves the marine mud waste issue in building works yet enables the industry to make another step forward on environmental protection for a sustainable community. Figure 10: Marine Mud Stabilization for Back-filling and building materials including paver blocks, planter curbs and roof tiles 2 The initiative won the 2011 Environmental Paper Award from the Environmental Division of the Hong Kong Institution of Engineers and the Gold Prize of the General Public Service Award from the Civil Service Outstanding Award Scheme

180 3.4.2 MODULAR DESIGN AND COMPONENT PREFABRICATION TECHNIQUES Besides prefabricated components and precast elements such as fabric reinforcement, semi-precast slab, precast façade and staircase, we also use volumetric precast kitchen and volumetric precast bathroom. Their implementation will reduce wastage and falsework and also improve the quality of the development as a whole. Figure 11: Precast Construction Techniques 4. CARBON EMISSION ESTIMATION We have developed a Carbon Emission Estimation (CEE) model to gauge the holistic carbon emission of new public housing developments, and we have chosen Kai Tak Site 1A as a benchmarking estate, with the standard New Harmony Block as a benchmark block. The model focuses on the major aspects of construction materials and building operations which have implications for carbon emissions, reduction and absorption during the whole building life from cradle to grave. We have identified six major aspects in the model materials consumed during construction; building structure; communal building services systems; renewable energy; planting; and demolition. Figure 12: Carbon Emission Estimation 5. WAY FORWARD We will monitor the implementation of those pilot green features in the two PRH estates, and extend the application of these features to other new projects in the pipeline. 8

181 PLANNING AND DEVELOPMENT OF SUSTAINABLE PUBLIC HOUSING PROJECTS IN INDUSTRIAL AREAS OF HONG KONG CHAN, HY HARRY 1 Chief Planning Officer / 2 Development and Construction Division, Hong Kong Housing Authority, Hong Kong Special Administrative Region, China. 1 Corresponding harry.chan@housingauthority.gov.hk, Tel: (852) , Fax: (852)

182 PLANNING AND DEVELOPMENT OF SUSTAINABLE PUBLIC HOUSING PROJECTS IN INDUSTRIAL AREAS OF HONG KONG ABSTRACT Finding sufficient land supply to meet the public housing flat production target always poses a major challenge to the Administration. To optimize the use of scarce land resources in Hong Kong, the Hong Kong Housing Authority (HA) works with Government to increase the housing land supply by developing public housing in industrial areas. Although we are striving hard to meet the quantitative flat production target under severe land, community and environmental constraints, we have never set aside our established qualitative goals for sustainability, which include providing homes for safe, green and healthy living in harmonious communities, developing properties that are functional and cost-effective, environmentally-friendly and people-oriented. This Paper aims to share HA's experiences on planning of public housing development in industrial areas and how HA makes uses of its sustainable planning and design approaches to optimize the flat production by overcoming various site constraints. Key Considerations include competing land uses and provision of supporting facilities and open space, measures to address industrial/residential interfaces, reprovision of existing uses, optimization of the development intensity and building height, preservation and adaptive re-use of the historic buildings, managing local aspiration and community engagement, etc. Two case studies are presented, including public housing developments in Fo Tan and transformation of Chai Wan Factory Estates by adaptive re-use, to illustrate different approaches, planning process, problems encountered, engagement with stakeholders, and creative solutions thus generated. Steady and timely provision of land is critical in meeting the challenge of increasing demand for public housing in Hong Kong. The HA s experience on the use of industrial land for public housing developments demonstrated the importance of flexible, proactive and sustainable approaches in meeting the above challenges for the short and medium term. Keywords: ADAPTIVE RE-USE; FACTORY ESTATE; INDUSTRIAL AREA; INDUSTRIAL/RESIDENTIAL (I/R) INTERFACE; PRESERVATION; SUSTAINABLE PLANNING/ DEVELOPMENT. 1. INTRODUCTION One of the objectives of the Government and the Hong Kong Housing Authority (HA) is to provide public rental housing (PRH) to low income families who could not afford private rental accommodation with a target to maintain the average waiting time for general applicants at around three years. To meet this objective, the HA will build 79,000 new PRH flats for five years from 2012/13 to 2016/17, and in January 2013 the Chief Executive announced in his Policy Address that we need to build 100,000 flats for the five year period starting from Despite the large existing stock and the flat production each year, the demand for public rental flats continues to rise. 2

183 As for the subsidized sales flats, the Government announced in 2011 the resumption of the Home Ownership Scheme (HOS) to meet the aspirations of middle-income families to buy their own homes. The HA will provide about 17,000 flats over four years from 2016/17 to 2019/20, and thereafter achieve a target of 5,000 new HOS flats per year. With the scarcity of land, finding timely available and suitable land to meet the flat production target presents a major challenge to the Government as well as the HA. With the decline of industrial activities in Hong Kong, there is scope to utilize the industrial land stock for residential use to boost public housing production and to speed up the restructuring of some of the obsolete industrial areas. Against the above background, this paper aims to share the HA s experiences and proactive approaches on the planning of sustainable public housing development in industrial areas of Hong Kong. 2. BUILDING A SUSTAINABLE COMMUNITY The concept of sustainability is now one of the major concerns to Hong Kong. We have been proactive in rising to this particular challenge and build sustainable and harmonious communities that are functional, cost effective and environmentally friendly. Sustainable development requires the full integration of the need for economic and social development with those of conserving the environment. We have to find ways to increase prosperity and improve the quality of life, while reducing overall pollution and wastes, reducing the environmental impact of our activities and helping to preserve common resources and in doing so, create a sound basis for a sustainable public housing programme. 3. PLANNING BACKGROUND 3.1. PLANNING DEPARTMENT S AREA ASSESSMENTS OF INDUSTRIAL LAND IN THE TERRITORY In view of the declining demand for industrial floorspace in Hong Kong, the Government has been exploring the feasibilities to rezone obsolete industrial land for other uses since late 1990s. In this connection, the Planning Department (PlanD) has carried out the Study to Review the Planning Framework for Reservation and Provision of Industrial Land. The latest Area Assessment 2009 for Industrial Land in the Territory completed in September 2010 identified a number of sites in Tsuen Wan West, Fo Tan, Fanling, Siu Lek Yuen and Tuen Mun for residential and other uses. Based on the Government s Assessments, we carried out site potential studies to ensure the identified sites are suitable for sustainable public housing development REDEVELOPMENT OF HA S FACTORY ESTATES FOR PUBLIC HOUSING DEVELOPMENT The HA has a number of factory estates. They were originally built by the then Resettlement Department and the HA between the 1950s and 1980s as part of the government s resettlement programme for rehousing squatter factories and cottage workshops displaced by natural disasters or land resumption. At its peak, the HA has a total of 17 factory estates. With the decline on demand for industrial floorspace in Hong Kong, we have ceased building new factory estates since As some of the factory 3

184 estates were obsolete and unable to meet the needs of modern industrial buildings, we had decided in 2000 to progressively clear some of the older factory estates. At present, only six remaining factory estates are still in operation. They have not been considered for redevelopment as their occupancies rates are steadily high, the industrial/residential interface problems are too serious or the sites are too small. Other factory estates have been redeveloped for public housing, open space, schools, or transformed to the Jockey Club Creative Arts Centre by adaptive re-use, etc. To meet the shortage of land supply for public housing, the HA is now redeveloping three factory sites for public housing developments. They are the redevelopment of Tai Wo Hau Factory Estate, San Po Kong Factory Estate and transformation of Chai Wan Factory Estate by adaptive re-use. 4. KEY CONSIDERATIONS FOR PLANNING OF SUSTAINABLE PUBLIC HOUSING DEVELOPMENT IN INDUSTRIAL AREAS 4.1 POLICY FRAMEWORK The Government s policy to transform industrial areas to non-industrial uses provides an overall policy framework for the proposed public housing developments. The PlanD s Area Assessment provides the planning support to facilitate the up-zoning of industrial areas identified for other uses. Our proposed developments in areas such as Fo Tan and San Po Kong are in line with the overall comprehensive land use planning of the districts, giving the impetus to upgrade and revitalize the area. 4.2 ENVIRONMENTAL SUSTAINABILITY PLANNING TO TACKLE INDUSTRIAL/RESIDENTIAL (I/R) INTERFACE PROBLEMS - Even though a site has been up-zoned, the process of actual land use transformation in an industrial area is a lengthy process. New residential developments near existing industrial uses might still be affected by industrial/residential (I/R) interface problems for an indefinite period of time. We have to take proactive and innovative steps to resolve the problems at early planning stage and apply design and technical solutions to mitigate adverse impacts to ensure that the I/R interface issues are fully addressed. REPROVISION OF EXISTING USES AND REMEDIATION OF CONTAMINATION OF SITES - Some of the industrial sites are occupied by temporary uses such as bus depot, abandoned vehicle surrender centre, car storage or repairing workshop. Timely evacuation or relocation of existing uses is critical to the development programme. We need to work closely with the relevant departments to relocate the existing uses. Since such land is usually contaminated, we need to allow time to carry out land decontamination works, and it will affect housing production programme. 4.3 SOCIAL AND ECONOMIC SUSTAINABILITY OPTIMIZING DEVELOPMENT POTENTIAL AND PROVISION OF SUPPORTING FACILITIES AND OPEN SPACE - While we are striving hard to optimize the development intensity and building height when developing public housing in industrial areas, we need to strike a balance among the development intensity, flat production and the provision of community facilities and open space. Considering that the existing facilities within the industrial areas are intended for the workers and not for the local residents and open space are limited, it is important to provide supporting facilities and open space to serve the new residents as well as the existing district needs. 4

185 COMPETING LAND USES AND PRESERVATION & ADAPTIVE RE-USE OF HISTORIC BUILDINGS - Although the industrial areas could release land for other uses, public housing might not be the only option. There are many competing land uses such as welfare, community, open space or private housing. We need to assess carefully the local community s aspirations against the needs from wider community. To create a sustainable plan, we seize every opportunity to integrate public s aspiration with the need for housing where possible. For example, we adapted the Cha Wan Factory Estate the last H-shape factory building in Hong Kong, for domestic use through which we were able to retain the heritage value of the building. MANAGING LOCAL ASPIRATION AND COMMUNITY ENGAGEMENT - There is a need to address both the housing need and the local aspiration so as to achieve a win-win situation. The proposed residential developments in industrial areas require rezoning of the sites. We need to gauge the views of District Council, stakeholders and local community and aspirations at early planning stage, and obtain their supports so as to minimize the possible delay on the development programme. We will proactively address their concerns into the proposal as far as possible, so as to help reduce the number of objections during the rezoning stage. This is an iterative process involving district planning, urban design, scheme design, plus multi-stakeholder engagement and negotiation process. We have achieved social sustainability through such planning approach. 5. CASE STUDIES OF SUSTAINABLE PUBLIC HOUSING DEVELOPMENTS IN INDUSTRIAL AREAS The cases of the proposed PRH development at Fo Tan and the proposed transformation of Chai Wan Factory Estate by adaptive re-use highlighted the key planning processes of sustainable public housing developments in industrial areas and how we overcome various constraints to achieve successful outcomes CASE STUDY 1 PROPOSED NEW PRH DEVELOPMENT IN FO TAN INDUSTRIAL AREA This brownfield site, mainly zoned Industrial ( I ) in Fo Tan Industrial Area, was identified in the Area Assessment 2009 for residential use. It is currently occupied by the temporary bus depots, temporary car park, car repairing workshops, abandoned vehicle surrender centre and 10 private lots MAJOR CHALLENGES AND OUR PROACTIVE PLANNING APPROACH OPTIMIZING DEVELOPMENT POTENTIAL AND PROVISION OF SUPPORTING FACILITIES - At the outset of the site potential study stage in 2007, we were only studying a small piece of land of about 1.8 ha with plot ratio restriction of about 2.5 and building height limit of 20 storeys producing 740 flats. Through our continuous discussion with PlanD for about 2 years and after a series of technical studies, the site area was enlarged to 4.1 ha by amalgamation of adjoining lots, and plot ratio was increased to 5 with permissible building height raised to 37 storeys. As a result, the flat production was significantly increased from 740 to about 4,200 flats, thereby providing more comprehensive facilities and creating a more vibrant neighbourhood. RESOLVING I/R INTERFACE ISSUES TO ENSURE ENVIRONMENTALLY SUSTAINABILITY - Despite the site is located slightly away from the active industrial node, it is still partly within the 100m industrial buffer zones and is subject to I/R interface problems in particular the fixed noise source from the cooling towers at the adjacent Data Centre (Figure 1). 5

186 Legend Public Housing Site at Ex-Fo Tan Industrial Area 100m buffer distance from BOC Building 100m buffer distance from other adjacent industrial buildings Figure 1: 100m Buffer Zones from Adjacent Industrial Buildings To overcome the I/R interface problems, we took a proactive approach in achieving integration of the development with the immediate surroundings. We proposed a 3- storey retail and welfare block at the south-eastern part of the site to create a barrier between the residential development and the industrial buildings (Figure 2). This block with a landscaped roof would accommodate the planned supporting facilities such as wet market, retail shops, car park, bus bays, kindergarten, Day Care Centre for the Elderly, etc., serving not only the PRH development but also the local community. For the adjacent Data Centre, we started the dialogue with the owner representatives and obtained their agreements to install at source acoustic treatments for the noisy cooling towers on the building roof. This could help us to address the noise problem from the cooling towers and allow us to design a better layout. REPROVISIONING THE EXISTING USES - There were an existing temporary bus depot, a temporary open carpark and a government abandoned vehicle surrender centre within our site. We took proactive approach and liaised with the government departments on identifying some possible reprovisioning sites in other districts. By doing so, we can resolve the reprovisioning issue and advance the availability dates of our site. Legend Figure 2: 3-storey Retail and Welfare Block 6

187 ENGAGING LOCAL COMMUNITY TO ENHANCE MUTUAL UNDERSTANDING - Since the site required rezoning, we adopted a proactive approach to sound out the planning intention of the site to Sha Tin District Council (STDC) at early planning stage in Initially, STDC was concerned about the inadequate project information such as the transport and welfare provision. We explained to STDC that our intention was to seek their early comments so that their concerns can be incorporated. With STDC s initial support, we proceeded with the preparation for the rezoning. In 2011, we refined our scheme and obtained STDC s support. In 2012, STDC set up a Working Group on Land Development to offer comments to the Government on major land development projects at the early planning stage. We took advantage of this opportunity and invited the Members for a site visit to present our PRH and HOS sites in Fo Tan and Sha Tin. Despite the additional workload, we see this as a golden opportunity to promote partnering between HD and STDC, in keeping with our caring culture to build harmonious community. After the STDC consultation, we continued to follow up their requests for improvements on traffic, public transport and cycle track issues that extend beyond our adjoining neighbourhood. REZONING INDUSTRIAL TO RESIDENTIAL (GROUP A) FOR TIMELY FLAT PRODUCTION - In the past, the Government only considered rezoning industrial sites from I to Residential (Group E) ( R(E) ) for a better control on environmental issues. However, our site was successfully rezoned to Residential (Group A) ( R(A) ) direct instead of R(E). This was mainly contributed by early completion of the technical assessments to well justify our residential proposal is environmentally acceptable. The layout design, no podium structure, building height profile, road widening and pedestrian linkage were agreed at the early site potential study stage. The R(A) zoning greatly streamlines the overall planning procedure and avoid the need for extra time and resource to submit planning application to the Town Planning Board (the Board) SUCCESSFUL OUTCOMES Through continuous discussion with the concerned departments, we fully utilize the valuable land resource by increasing the site area and development intensity. Also, we took lead to early engage the STDC and sound out our planning intention of the site and provide prompt responses to their concerns. We took proactive actions to resolve the I/R interface issues to ensure environmental sustainability of the development. More important, without compromising the environmental considerations, this is almost the first successful case of rezoning I site directly to R(A) site so as to speed up the development programme and flat production CASE STUDY 2 PROPOSED TRANSFORMATION OF THE CHAI WAN FACTORY ESTATE FOR PUBLIC RENTAL HOUSING CUM MUSEUM FOR HA S FACTORY ESTATES The Chai Wan Factory Estate (CWFE) is located at the Chai Wan Business Area adjoining the Chai Wan MTR Station (Figure 3). It is a six-storey walk-up block built in The factory estate has been evacuated since end The site of CWFE and the adjacent bus terminus was zoned as CDA which was intended for comprehensive development/redevelopment for residential and or commercial uses in The after use of the site had evolved with changing circumstances over the years. While the HA had been pursuing to redevelop the site for public housing, commercial development was not precluded in view of the prime location of the site. 7

188 Figure 3: Chai Wan Factory Estate, the last Surviving H-shaped factory estate building in Hong Kong MAJOR CHALLENGES AND OUR PROACTIVE PLANNING APPROACH RESPONDING POSITIVELY TO PUBLIC S ASPIRATION - HA s original plan was to provide some 400 flats through redevelopment. However, in the recent years, there has been increasingly strong demand to preserve the last H-type factory building in Hong Kong (Figure 3). The proposal was first initiated by the Eastern District Council and as the strong aspiration transpired, HA took the initiative to reassess the original redevelopment plan. Through active engagement with concerned LegCo Members, Eastern District Council members and local concern groups, a concept marrying the conservation need while meeting the short term demand for public rental housing was conceived. The proposed transformation by adaptive re-use of the building will provide some 190 flats for singletons and small families in 2015/16. MEETING THE ENVIRONMENTAL CHALLENGES AND THE NEED TO PRESERVE THE BUILDING S HERITAGE VALUE - To convert a factory building for residential use is in itself a challenging proposition, let alone preserving its heritage value. Apart from the change of use, the project has to preserve the original shape, structure, building elements and appearance of the factory building as far as practicable. To this end, HA took proactive steps to engage experts to conduct Heritage Impact Assessment (HIA) to ensure that the conservation principles will be met. The HIA of this project was endorsed by the Antiquities Advisory Board in April The conversion plan also needs to take into account the residential/industrial interface issues and the noise impact from the nearby bus terminus, railway and adjacent roads (Figure 4). To meet the above challenge while keep the block in its original shape as far as practicable, all air and noise sensitive receivers will be facing inward into the courtyard. The original H-shaped build form has two distinct courtyards which will best serve the above purpose (Figure 5). With landscaping and beautification, the courtyards will become activity nodes and estate gathering place. ENGAGING DISTRICT COUNCIL AND LOCAL CONCERN GROUPS - During initial engagement with some members of the Eastern District Council, we gathered the wish list from local communities on the proposed uses to be incorporated into the project. In response, we have incorporated in our preliminary plan to display the history of Chai Wan Factory Estate in public area such as G/F courtyard, access routes, lobby and corridors. We will conduct further public engagement with the Eastern District Council and local interest groups to work on the details SUCCESSFUL OUTCOMES The proposed conversion plan of Chai Wan Factory Estate has well served the public s interest on preserving the local history while meeting the need for public housing. By 8

189 converting the last H-shaped factory estate in Hong Kong into residential cum community use, we have given the building a new life. Comparing to the original demolish and rebuild approach, the project will generate less construction waste and advance the delivery of new flat production by two and a half years. Figure 5: The wrapped around corridor is a distinct feature of the factory building Figure 4: Site Constraints SUCCESSFUL OUTCOMES The proposed conversion plan of Chai Wan Factory Estate has well served the public s interest on preserving the local history while meeting the need for public housing. By converting the last H-shaped factory estate in Hong Kong into residential cum community use, we have given the building a new life. Comparing to the original demolish and rebuild approach, the project will generate less construction waste and advance the delivery of new flat production by two and a half years. 6. WAY FORWARD Land is a precious resource in Hong Kong. With the rapid rising demand for residential land, we need to continue to identify suitable land for housing development. With the shortfall of readily available residential sites, we need to reconsider sites that were previously ruled out for residential use. While the Government continues to study the use of green field sites such as agriculture land, green belt land in the New Territories for residential developments as a long term measure, the use of brown field sites in industrial areas provides a medium measure to increase land supply for housing. Although the policy and planning framework established by the Government provides a direction and support for the future development, we still need to deploy very intensive resources and efforts to realize the projects. The case studies demonstrated that how we overcame various constraints and successfully plan for the public housing developments in industrial areas. The length of time required to plan and resolve various constraints emphasizes the complexity of residential development in industrial area. We take great pride in meeting the housing need of the people and at the same time providing good quality, harmonious and environmentally-friendly homes that people are happy to live in. One of the keys to success lies in adopting proactive and integrated planning approaches to tackling town planning procedure, resolving I/R interface issues, addressing the community need and aspiration, engaging DC, carrying out consultation in an open manner, and working closely with government departments and stakeholders. 9

190 7. CITATIONS AND REFERENCES Planning Department, Report on Area Assessments 2009 of Industrial Land in the Territory (Final Report) [online]. Available from: [Accessed 30 December 2012]. 10

191 PLANNING AND DESIGN FOR SUSTAINABILITY A CASE STUDY OF LAM TIN ESTATE OF HONG KONG Rosa S.F. Ho Lok and Tim M.W. Li Development & Construction Division, Hong Kong Housing Authority, Hong Kong, China 1

192 PLANNING AND DESIGN FOR SUSTAINABILITY A CASE STUDY OF LAM TIN ESTATE OF HONG KONG ABSTRACT The Hong Kong Housing Authority (HKHA) has been providing affordable and sustainable public housing for people in need since With rapid growth of population in the 1980s, the old Mark series blocks with inferior living conditions had to be redeveloped. HKHA implemented the comprehensive redevelopment programme in Lam Tin since 1990s and Lam Tin Estate was the final phase which took up its name as suggested by the community. This paper presents Lam Tin Estate as a case study to illustrate the sustainable design approach in the dense urban environment, including the study of micro-climate in assisting planning and design for comfort living for our tenants; the extensive use of grid-connected photovoltaic (PV) panels for the economical use of renewable energy and implementation of roof greening and vertical greening to reduce heat island effect. Last but not the least, the engagement of the stakeholders including proactive community building through workshops and enhancing quality management through partnering with stakeholders. This is a demonstration project in building a sustainable community and manifestation of our core values of 4C s, namely Caring, Customer focused, Creative and Committed. It took a great journey for HKHA s project team to work with the stakeholders and it turned out to be a rewarding experience with high user satisfaction, as reflected in the high satisfaction rate in the customer survey conducted after occupation. The experience we gained in Lam Tin Estate made us believe that by proactively engaging the community in the development process and employing green technologies in the design will bring forth fruitful outcome for a harmonious and sustainable living environment mostly valued by the project team and the users. Keywords: sustainability, caring, community engagement, greening, sustainable design approach 1. INTRODUCTION Hong Kong Housing Authority s (HKHA) primary role is to provide subsidized public housing to low income families who cannot afford private rental accommodation. The public housing programme has evolved to meet public expectations, from an emergency housing programme in the 1950 s, to the more sophisticated public housing services that we provide today, covering planning, design, construction, management and maintenance aspects. The improvements we made are a direct response to public demand as society has prospered and public aspirations have changed. One of our key missions is to provide affordable quality housing with a healthy living environment, thereby improving the quality of life in Hong Kong. This, we believe, allows our tenants to contribute more effectively to the community and the local economy, and allows the HKHA to contribute to the overall sustainability of Hong Kong. Lam Tin Estate is a demonstration project in building a sustainable community and manifestation of our core values of 4C s, namely Caring, Customer focused, Creative and Committed. It took a great journey for HKHA s project team to work with the stakeholders and it turned out to be a rewarding experience with high user satisfaction, as reflected in the high satisfaction rate over 96.6% in the customer survey conducted after occupation. 2

193 1.1 OVERVIEW OF PROJECT REQUIREMENTS The following factors press the need for redevelopment: Under-utilization of land development potential Substandard habitable space (average area per person is sq.m.) Substandard provision for safety, hygiene, ventilation and lighting etc. Poor Sanitation Poor natural ventilation and lighting Substandard building services provision for basic comfort Figure 1 Old Lam Tin Estate (left) New Lam Tin Estate (right) Lam Tin estate is the last phase of the Lam Tin area redevelopment which was completed in June The new estate occupies an area of 2.7 hectares and has four non-standard 40-storey residential buildings providing 3,036 units. Green living is the main theme of the estate design, featured with the largest grid-connected photovoltaic (PV) system in public housing in Hong Kong. We made use of micro-climate studies in estate design and conducted extensive community engagement throughout the redevelopment process. Project particulars: Four 40-storey non-standard rental blocks 38 domestic floors with elevated garden deck 3,036 rental flats Design population was 8,568 LGV carport (22 spaces which were late additions in response to community request) Estate management office Footbridge, lift tower and covered walkway linking to completed estate of earlier phases External works 1.2 SUSTAINABLE DESIGN APPROACH In planning and design for the development, we adopted Sustainable Design Approach by integrating environmental, social and economic factors through: 1. Enhancing energy efficiency through application of micro-climate studies. 2. Reducing resources consumption by using renewable energy. 3. Reducing urban heat island effect through maximizing greening. 4. Enabling continuous improvement through Stakeholders Engagement. In the following sections, we will layout the facts and results to illustrate the achievements made possible through various means in Sustainable Design Approach. 3

194 2. ENHANCING ENERGY EFFICIENCY THROUGH MICRO-CLIMATE STUDIES Micro-climate studies involve the application of latest proven scientific technologies, including computational fluid dynamics simulations, wind tunnel tests and daylight simulations tools, etc. The innovation application of those established technologies enable designers to compare different options and help to fine-tune architectural layout and details based on qualitative and objective analyses. This project was one of the first batches of public rental housing projects where comprehensive microclimate studies were applied during planning and design stages. 2.1 THE DESIGN ENHANCEMENT THROUGH APPLICATION OF MICROCLIMATE STUDIES Capture Wind Environment and Natural Ventilation Wind corridor enhances the wind environment of the site with average pedestrian wind speed of 1 m/s; A deck garden linking all domestic blocks and ventilation bays at first floor enhances wind circulation through domestic blocks by over 50%; and Cross ventilation at ground floor entrance lobby and lift lobby of typical domestic floors enhances building permeability for natural ventilation and daylight by at least 15%. Optimise Daylight and Sun-shading Maximization of window area at typical floor lobby and corridor enhances daylight penetration by 10%; and Entrance plaza design corresponds to sun-shading pattern to enhance thermal comfort when external activities are conducted. Induce Thermal Comfort Environmental façade design and over 30% greening ratio mitigate solar heat gain in domestic flats. 2.2 ENVIRONMENTAL FAÇADE We adopted Environmental Façade Design in the domestic block based on Life Cycle Costing considerations. Optimum horizontal shading fins of varying overhanging width up to 575 mm were designed to mitigate solar heat gain. Figure 2: Micro-climate studies and Life-cycle costing studies facilitate the designers to determine the locations and size of solar shading device in a holistic design approach. 4

195 3. REDUCING ENERGY CONSUMPTION THROUGH USING RENEWABLE ENERGY 3.1 PHOTOVOLTAIC PANEL (PV) AS A TESTING TRIAL Seeking to improve energy saving, new technologies were tried out to capture more energy in this project. A total of approximately 248m 2 mono-crystalline silicon PV modules at the total capacity of 33kW were installed on the upper roofs of three domestic blocks and part of the covered walkway. The installation was integrated in the architectural and structural design: The PV system is connected directly to the power distribution network of the buildings as a power source secondary to the conventional electrical power supplied by the power company. The grid-connected design obviates the need of power storage batteries, thus resulting in lower installation and maintenance cost. The panels were installed at upper roofs of domestic towers to capture the maximum natural light; Three transparent PV panels were installed at roof of covered walkway located at main pedestrian thoroughfare for educational purpose with LCD display monitor indicating the on time power generation of the system; Annual saving in electricity (approximately 43,000 kwh) by using the photovoltaic system to generate electricity for the public areas; Annual energy saving (approximately 652,174 kwh of electricity) for artificial lighting at common area is 13%; and Annual saving in energy consumption equals to a reduction of 2,800 tonnes of carbon emission per year. Figure 3 PV panels installed on the upper roof for the maximum solar absorption (left), PV panels installed over the pedestrian level to enhance awareness on the use of solar energy to the building users. (right) 3.2 GREEN LIVING EDUCATION A publicity display system was located at the thoroughfare and was specifically designed and incorporated with the PV system to promote the environmental awareness of tenants and people passing-by. Two LCD monitors were installed at the open venue and the upper lobby of lift tower respectively for display of the real time PV data for information of the public. We also installed interactive games at exhibition corner of the deck garden based on intelligent technology, for playing by tenants of all ages to arouse their awareness for green living habitat. 5

196 4.0 REDUCING URBAN HEAT ISLAND EFFECT THROUGH GREENING MAXIMIZATION 4.1 MAXIMIZED GREENING The main cause of the heat island is modification of the land surface by urban development which uses materials that retain excessive heat. To reduce urban heat island effect, we tried to reduce the concrete hard surface and increased the greening area as far as possible. Other than the planting at grade, we experimented different means to increase the greening area, such as roof greening over the covered walkway, hydroseeding on surrounding slopes, vertical greening on the west facing walls, preserving the trees on site, etc. The overall greening ratio of 26.3% is achieved. 4.2 ACTION SEEDLING Other than the greening effort on hardware design and provision, we also engaged the tenants, contractors and local community in the "Action Seedling" greening activity to create a sustainable environment and foster sense of belonging and social responsibility. With the collaborated efforts of the contractor, we distributed seedling plants to nearby primary school children in late 2008 and prior to the contract completion, for them to nurture the plants, which were then transplanted back to the planters of the new estates in Figure 4: Action seedling event held on 8 November 2008 (left) and 28 November 2009 (right) 4.3 COMMUNITY FARM The continuous engagement of the tenants on the greening education is carried through to the Community Farm. The Estate Management Advisory Committee (EMAC) and residents made good use of the Community Farm designed at one corner of the site. Gardening training was provided with good response from residents. The Community Farm not only offers a venue for tenants enhanced communication and participation, it also promotes human relationship and sense of belonging. Figure 5 : Community Farm location (left), View inside the community farm (right) 6

197 5. ENABLING CONTINUOUS IMPROVEMENT THROUGH STAKEHOLDERS ENAGEMENT 5.1 COMMUNITY SPIRIT Figure 6: Time line of the community engagement process In 2008, we organized a total of four community design workshops jointly with Kwun Tong District Council, Lam Tin Area Committee, local schools and non-government organizations (NGO) to work out the design of the deck garden linking all domestic blocks. Through the community- engagement activities, project team worked directly with the stakeholders to create a distinct and sustainable master layout and design as follows: Provision of elevated deck garden for heritage and green living educational elements with leisure sitting-out area and physical exercise area; Provision of light goods vehicles (LGV) parking block to minimize the noise nuisance; Provision of tensile cover in the estate plaza for shelter and performance stage; Provision of more sitting benches in the ground-floor lobby and external areas; Colour scheme and naming of the domestic blocks giving a character to the development in the locality. 5.2 PARTNERING SPIRIT The Housing Authority has been an active leader in promoting Partnering in Hong Kong Construction Industry. We adopted the Partnering approach to engage our stakeholders, including planners and designers, building, maintenance and property services experts, tenants, users and workers, as well as the community at large for sustainable housing development. We make constant improvement to our system and measure against established targets to ensure that our expertise meets our needs and our services meet the tenants aspirations. 5.3 PROJECT SPECIFIC PARTNERING An Initial Partnering workshop was held on 30 November 2006 when the contract was commenced to align the project and construction teams. A Close-out Partnering Meeting was held on 8 December 2009 to review the performance of the partnering arrangement throughout the contract. About two years after occupation, Post completion Review Workshop cum Joint Site Visit was held on 24 May 2011, participated by project team, contractor s representatives and housing manager to gauge feedback and review the handover and maintenance services and overall customer satisfaction. This also serves as a knowledge sharing platform amongst various stakeholders with an aim for continuous service improvement. 7

198 6. CONCLUSION 6.1 HIGH SATISFACTION RATE About one year after occupation, we engaged consultant to carry out comprehensive resident survey through questionnaires and home visits in order to gauge customer s feedback and satisfaction level. A total of 344 interviews were conducted, out of the total 2,938 households residing in the estate. The survey result shows that 96.6% of the households are satisfied with the estate as a whole, and no household felt unsatisfied. 6.2 A SUSTAINABLE COMMUNITY FOR ALL This is a demonstration project showing the building of a sustainable community and manifestation of our core values of 4C s, namely Caring, Customer focused, Creative and Committed. It took a great journey for HKHA s project team to work with the stakeholders and it turned out to be a rewarding experience with high user satisfaction as reflected in the high satisfaction rate in the customer survey conducted after occupation. Figure 7: Heritage Trail showcases the history of the old Lam Tin Estate (left), Public Engagement through community art making (right) Public housing in Hong Kong has made an enormous contribution towards the well-being of the local community for the past 60 years. The experience we gained in Lam Tin Estate made us believe that by striving for sustainable planning, design, construction and management through adoption of suitable technologies and proactively engaging the community, listening to their needs and involving them in the development process help to bring a win-win situation for all parties and thus build up a sustainable living environment. Figure 8: Community artwork Infinity symbolizes the use of Renewable Energy (left), PV panel installation on the roof of the domestic blocks (right) 8

199 LIVING IN SUSTAINABILITY - A CASE STUDY OF HONG KONG PUBLIC RENTAL HOUSING ESTATES Ir. S.T. CHAN 1 WILLIAM W.L. HO 2 Ms. WINNIE W.Y. LO 3 DICK L.S. CHAN 4 DANIEL T.M. LEUNG 5 THE HONG KONG HOUSING AUTHORITY, HONG KONG st.chan@housingauthority.gov.hk, Tel:(852) , Fax: (852) william.ho@housingauthority.gov.hk Tel:(852) , Fax: (852) wy.lo@housingauthority.gov.hk Tel:(852) , Fax: (852) ls.chan@housingauthority.gov.hk, Tel:(852) , Fax:(852) tinming.leung@housingauthority.gov.hk, Tel:(852) , Fax:(852)

200 LIVING IN SUSTAINABILITY - A CASE STUDY OF HONG KONG PUBLIC RENTAL HOUSING ESTATES Abstract Sustainability is one of the key maintenance strategies for public rental housing (PRH) estates adopted by the Hong Kong Housing Authority (HKHA). Efforts have been made in improving the building performance in environmental, social and economic aspects of the existing estates through Estate Improvement Programme (EIP). The EIP is a holistic, peopleoriented and cost-effective approach to bring the existing estate provisions closer to current standards befitting tenants needs, social harmony and heritage conservation. The EIP with the theme Living in Sustainability at Kwai Shing West Estate (KSWE) is one of the examples. Environmental To promote effective energy use and reducing electricity consumption, KSWE has adopted good energy saving practices and measures to cut down electricity consumption and enhance environmental protection to achieve ISO50001 Energy Management System and BEAM Plus (Existing Buildings) certification. Environmental Protection Windows are set up at lift lobbies to monitor the electricity, gas, water consumption to encourage community s awareness of sustainability living. Other provisions, like, green roof and twin water tank system also improve the quality in dense urban living and water saving. Social Built in 1975, KSWE currently has a population of 14,800, of which 30% are elderly. To address the needs of the ageing population, the estate has been upgraded with barrier free access provisions, including new lift towers, covered walkways, ramps; accessible toilets, tactile guide-paths, handrails and parking space. We also encourage community participation, e.g. Tree Ambassadors Scheme, to invite tenants actively taking part in estate conservation programmes. Economic Through improvement of its commercial facilities, e.g. market re-ordering and shop conversions, not only the community s changing needs are met, it also improves the revenue. The EIP at KSWE has well demonstrated how the HKHA strives for sustainability in old aged PRH estates and its commitment to maintain a quality living environment for the tenants. 2

201 1. INTRODUCTION Kwai Shing West Estate Estate layout plan Sustainability is one of the key maintenance strategies adopted for the public housing estates (PRH) by the Hong Kong Housing Authority (HKHA). To upkeep the provisions and facilities of an old estate so that it can continue to provide tenants with a decent living environment meeting their up-to-date needs, an Estate Improvement Programme (EIP) will be formulated for estate of about 40 years old after detailed structural appraisal under the Comprehensive Structural Investigation Programme (CSIP) 1 and confirmed as structurally sound and economically viable for maintainance. Kwai Shing West Estate (KSWE) is one of the estates completed the CSIP in 2009 and confirmed that all the building blocks are structurally safe which can be sustained for the next 15 years. The findings of the CSIP favourably supported KSWE to implement the Estate Improvement Programme (EIP). The EIP for KSWE was themed as Living in Sustainability which aims at bringing the existing estate provisions closer to the current standard through an optimum scope of cost-effective improvement works. KSWE was completed in 1975 with a site area of 85,000m 2 at Kwai Shing Circuit, Kwai Tsing District. With its unique characteristics built on hillside, it consists of ten slab block buildings of 7 to 25-storey high, two car park buildings and a shopping centre. It is a mature estate with a total number of 5,260 flats. Amongst the population of 14,800, 30% (4,430 persons) are elderly tenants, 60% of the households have elderly member aged 60 or above and about 60 flats are occupied with members of physically disabilities. To address the ageing problem, we have paid particular attention to the special needs of the elderly and disabled tenants, their living pattern and their integration with the younger generation. There is one important consideration in designing the improvement works for an old estate such as KSWE, i.e. many tenants have grown up and grown old with the estate and have spent their lifetime in the estate. 1 The Comprehensive Structural Investigation Programme (CSIP) was launched in 2005 targeting at estates approaching 40 years of age and at a 15-year interval afterwards. CSIP looks into the structural integrity and determines if the public rental housing estate is economically viable to maintain. 3

202 The following paragraphs outline some of the key planning considerations of the EIP for KSWE which demonstrate the efforts and resolute actions in the aspects of environmental, social and economic to create a green, healthy, comfortable and sustainable environment for this 38 years old housing estate. 2. ENVIRONMENTAL In order to enhance the environmental performance, KSWE has implemented the following improvement works: 2.1 CERTIFICATION TO BEAM PLUS FOR EXISTING BUILDINGS KSWE has been selected as one of the pilot estates for certification to the Building Environmental Assessment Method (BEAM) Plus for Existing Buildings which is used to benchmark the environmental and sustainability performance of the buildings. Under this assessment, a weighting over different environmental performance categories, including site aspects, material aspects, energy use, water use and indoor environmental quality, would be evaluated. Having taken into account of the existing environmental performance as well as the improvement measures to be adopted, we target to achieve Gold or above grading under the BEAM Plus. The improvement measures are grouped into five categories: i) data and records gathering (e.g. environmental purchasing records, waste records, etc.), ii) procedures/manuals/guidelines development (e.g. tenant guidelines), iii) site measurements (e.g. water quality survey), iv) technical studies (e.g. waste audit, energy audit, carbon audit and water audit) and v) building improvement works (e.g. modification of existing refuse storage areas with independent mechanical air filtration system, replacement of water cistern and urinal flush valve from single flush to dual flush system, sensory water taps for public toilets and implementation of ISO Energy Management System.) BEAM Plus is a new scheme to the existing PRH estates. The above-mentioned enhancement works represent just a portion of the total scope. To achieve the BEAM Plus Certification, the estate management has devoted considerable efforts to improve the health, energy efficiency and environmental sustainability of the buildings to ensure that the living environment of the tenants are enhanced. 2.2 IMPLEMENTATION OF ISO ENERGY MANAGEMENT SYSTEM (EnMS) With a view to reduce the emission of Greenhouse Gases (GHG) which are globally recognized as the culprit of climate change, the HKHA has committed to continually improve the energy performance standards of operation, planned maintenance and improvement works for PRH and related services. While full ISO certification for all existing PRH estates is planned in mid 2015, KSWE was selected as the pilot estate and successfully obtained the ISO EnMS certification in June This EnMS Certification covers the central building services installation of communal areas of the domestic blocks plus the nearby external lighting circuit. In the implementation of EnMS, improvement works for installations/facilities accounting for a significant energy use, such as public lighting, lift and water pumping systems, are actively explored and energy management opportunities are identified. For example, the public lighting improvement programme for all the domestic blocks in KSWE was carried out in October 2012 and completed in January 2013 by using 4

203 energy efficient product i.e. electronic ballast with registration under EMSD s Energy Efficiency Labeling Scheme. With the completion of the public lighting improvement programme, there is a significant reduction of energy use of at least 10% in the communal areas of the domestic blocks of KSWE. In 2012/13, the electricity consumption for all domestic blocks at KSWE was 35.4 kwh/m 2. With the energy saving initiatives being put in place, it is anticipated that the energy performance in 2013/14 will be further reduced to about 32.5 kwh/m ENVIRONMENTAL PROTECTION WINDOW (EPW) Energy screen display the energy consumption To arouse tenants awareness of energy conservation and environmental sustainability, the Environmental Protection Window (EPW) was initiated in the EIP through installation of a used liquid-crystal display (LCD) panel at the ground floor lift lobby of every domestic block to show the periodic consumption of electricity (both tenants and communal), gas (tenants only) and water (communal only) for individual block. Periodic comparisons on various consumption performances of the blocks within the same period in previous year, and periodic comparisons of various energy use indexes of individual block with the average figures of all PRH blocks in Hong Kong can be carried out. 2.4 GREEN ROOF & VERTICAL GREENING The provision of green roof at the shopping centre located at the centre of the estate, not only provides aesthetics enhancement to the neighbourhood, it also reduces the surface temperature as compared to hard roof surface by about 4 O C, reinforces building insulation and energy efficiency, lowers the overall heat island effect and increases the overall green ratio to 28% of the total Construction Floor Area of the estate. We have also identified other low rise structures in the estate suitable for vertical greening, such as pump rooms, which are generally welcomed by the tenants. Green roof at shopping centre podium Vertical greening at pump room 5

204 3. SOCIAL 3.1 TWIN TANK SYSTEM The twin tank system for portable water supply system for domestic blocks has been implemented in many new estates. The objective of the twin tank system is to provide uninterrupted water supply to tenants, even during cleansing of water tank. While recognizing the social and environmental benefits, the economic implication has also been taken into account. The twin tank system in KSWE utilizes the existing two water tanks located on the same roof with modification of pipe-works. Such arrangement is more cost-effective as it retains the existing structure to avoid demolition and construction waste, but at the same time improve the quality of living and sustainability of the estate. Modification of existing water tanks to provide the twin tank system at domestic block 3.2 BARRIER-FREE ACCESS & CONNECTIVITY Around 30% of the population in KSWE aged 60 or above and the percentage is growing. The needs of providing barrier-free access (BFA) and improving connectivity within the estate becomes inevitable. Addition of lift towers have been newly completed for building blocks with no lift provision previously. The new lift towers have made significant improvement of BFA as well as the connectivity of the estate, and welcomed by the tenants. Other BFA improvement works, such as the tactile guidepaths, railings at staircases, ramps, accessible parking space, unisex toilets, etc. at communal areas have also taken due consideration of the valuable feedbacks from Persons with a Disability on BFA facilities. A weather-protected pedestrian walkway network is provided by extension of the existing covers along the elevated walkways at Blocks 6 and 9 and construction of a new covered walkway at the pedestrian footpath from Blocks 1 to 5. This weather-protected walkway network enhances the connectivity amongst building blocks and major facilities of the estate. Addition of lift tower at Block 4 BFA improvement works Extension of covers at Shopping Centre 6

205 3.3 COMMUNITY ENGAGEMENT WORKSHOP The Estate Tree Ambassadors (ETA) Scheme volunteered by tenants has been implemented in KSWE since The ETA Scheme encourages tenants to actively participate in estate trees conservation activities, education and promotion programmes. The external areas and open space have always been popular in PRH estates for recreational activities and social gathering. During the planning stage of the EIP, consultation was widely conducted to collect views of the stakeholders. Community Workshops were held to obtain inputs and ideas from the stakeholders including the tenants, Estate Management Advisory Committee (EMAC) members, non-government organizations (NGOs), local District Council (DC) members and neighbourhood schools etc. The community workshops also help to gauge the views and expectations of the tenants and local community. Through a series of social activities, focus group meetings and workshop, stakeholders feedbacks are collected and consensus is drawn as we develop the detailed design of the open spaces. Recognizing the contribution of people in driving the community to a unified goal, we engage the community, empower people and foster participation so as to raise their environmental awareness, instill a culture of environmental protection and sense of belonging. Improvement of Elevated Walkway - Art Gallery with exhibits by children from neighbourhood schools Social gathering at the open space 4. ECONOMIC 4.1 SHOPPING CENTRE IMPROVEMENT WORKS The existing 3-storey shopping centre consists of retail shops on G/F, a market on 1/F and a shopping lane at podium with a total of 21 retail shops and 85 market stalls. The occupancy rate for the retail shops is 96%, whereas, for the market stalls is only 26%. As one of the EIP strategies for KSWE, the commercial facilities will be enhanced to meet up-to-date shopping needs. The existing shopping centre will be renovated with additional public toilets and accessible unisex toilets. Whereas the G/F storerooms will be converted to retail facilities, the market stalls and trades of the retail shops will also be re-ordered to increase the retail areas and improves the shopping environment. Such renovation and shops re-ordering works will, in return, improve the occupancy rate, increase revenue and bring in new job opportunities to the district. 7

206 Re-ordering of market stalls and retail shops Provision of unisex accessible toilet and children fitments in male & female toilets 5. CONCLUSION As one of the biggest public sector developers in Hong Kong, the HKHA upholds the building sustainability strategy with social, environmental and economical principles in pursuit of harmonious living environment. The HKHA is committed to promote a green and healthy living in PRH estates and to provide a sustainable living environment for the tenants. In order to achieve sustainable living, we have been striving for environmentally friendly, socially welcoming and cost-effective solutions for the EIP in KSWE. A series of programmes have been implemented to address the various aspects with a goal of improving the sustainability of the estate. Regarding the environmental aspect BEAM Plus Existing Buildings is engaged to benchmark the environmental and sustainability performance of the buildings, ISO Energy Management System is implemented to improve energy performance, the Environmental Protection Window helps to promote tenants awareness on energy conservation. On the social aspect the provision of barrier-free access and connectivity of the buildings and major facilities of the estate are improved to meet the needs of the ageing population. Community engagement workshops are conducted to obtain views and gauge expectation of the stakeholders regarding open spaces design and enhance their sense of belongings. With respect to the economical aspect, the vacancy rate of the market will be reduced through re-ordering and re-alignment of shop stalls and optimize the retail areas by conversion of store rooms to retail facilities to improve the shopping environment. All in all, we will continue to contribute towards the well-being of the community and provide a safe, healthy and sustainable neighbourhood estate like Kwai Shing West Estate so that our tenants can all enjoy living in sustainability. 8

207 DEVELOPMENT OF A LOCAL EMBODIED CARBON DATABASE FOR CONSTRUCTION MATERIALS Jack C.P. Cheng1, Irene M.C. Lo, Vincent J.L. Gan, Ran Jing, Jing L. Zhang Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 1 Corresponding Author cejcheng@ust.hk, Tel: (852) , Fax: (852)

208 DEVELOPMENT OF A LOCAL EMBODIED CARBON DATABASE FOR CONSTRUCTION MATERIALS ABSTRACT According to WWF, the construction sector was the second largest contributor to Hong Kong carbon footprint and emitted nearly 4 million tons of carbon dioxide in In addition to the operational carbon generated during building operation and maintenance, the embodied carbon of construction materials also contributes a significant part of the life cycle carbon emission in the built environment. Studies have shown that the embodied carbon of buildings is close to the operational carbon over 20 years, and contributes more than 30% of the life cycle carbon emission of buildings. In Hong Kong s construction sector, 85% of its carbon footprint was embodied in imported goods and services. Therefore, it is crucial to study the embodied carbon of construction materials and select the low carbon materials in order to achieve a low carbon built environment. This project aims to develop a local embodied carbon database, namely ECO-CM (Embodied Carbon Of Construction Material), for the commonly used construction materials in Hong Kong. A Cradle-to-Site life cycle boundary was used in the ECO-CM database, which includes raw materials extraction and transportation, material manufacturing, and product transportation to the use site. As the fuel mix and material manufacturing and delivery in different areas may vary substantially, embodied carbon values are region-specific. Therefore, first hand data were collected from the material vendors through questionnaires for calculation. The methodology framework used in the development of the ECO-CM database is presented and illustrated in this paper. The completed ECO-CM database will provide a basis for selection of green materials, development of carbon labels, and estimation of building facility carbon footprint, thereby helping to construct a low carbon Hong Kong. Keywords: Cradle-to-Site; Embodied Carbon; Green Construction Materials; Life Cycle Assessment. 1. INTRODUCTION The global warming issue has attracted a great concern around the world in recent years. Greenhouse gas (GHG), a gas which absorbs and emits radiation within the thermal infrared range, is the major cause of global warming. United Nations Framework Convention on Climate Change has agreed that the future global warming should be limited to below 2.0 C (UNFCCC, 2010). According to WWF, the building construction sector is the second largest contributor to Hong Kong carbon footprint (Cornish et al., 2011). Moreover, it was generally agreed that since the sources of Hong Kong s carbon emissions are concentrated in the power sector and building sector, the greatest opportunity for Hong Kong to reduce its emissions lies in these two sectors (Cornish et al., 2011). Embodied energy and carbon have attracted much attention recently. It has been shown that embodied energy and carbon can greatly influence the life cycle energy consumption and carbon emission of contemporary buildings. Therefore, estimating the embodied carbon of commonly used construction materials can help to provide a basis for prediction and reduction of GHG emissions in the construction sector. 2

209 Application of green construction materials plays a significant role in the carbon reduction of construction sector. There are several life cycle embodied carbon databases for the selection of green construction materials, such as Ecoinvent developed by the Swiss Centre for Life Cycle Inventories, the Inventory of Carbon and Energy (ICE) by the Bath University, and the Chinese Life Cycle Database (CLCD) by the Sichuan University. In Hong Kong, a local embodied carbon database namely Embodied Carbon of Construction Materials (ECO-CM) is under development by the Hong Kong University of Science and Technology (HKUST). The ECO-CM has several differences compared with other databases. First of all, the system boundary of this study is Cradle-to-Site, which covers partial product life cycle from raw material extraction to final product transportation. The CO 2, CH 4 and N 2 O emitted in the Cradle-to-Site life cycle boundary are considered in the calculation of GHG emissions. Moreover, this project targets to conduct Hong Kong-specific estimation of CO 2 emission using the first-hand data from material manufacturers and vendors. The first hand data were collected via company-level questionnaire surveys and interviews with stakeholders. Table 1: Life Cycle Inventories of Construction Material in Different Countries Region Construction Life Cycle Inventory (LCI) Institution System Boundary Switzerland Ecoinvent Swiss Centre for Life Cycle Inventories Europe United Kingdom China ELCD (European reference Life Cycle Database) ICE (Inventory of Carbon and Energy) CLCD (Chinese reference Life Cycle Database) European Union University of Bath, UK Sichuan University, China Gate-to-Gate Cradle-to-Gate Cradle-to-Gate Cradle-to-Gate Hong Kong Embodied Carbon Of Construction Materials (ECO-CM) HKUST Cradle-to-Site The embodied carbon values are region-specific. However, estimation of embodied carbon in the construction materials used in Hong Kong still relies heavily on overseas data, which may not be applicable to the construction industry in Hong Kong. A local carbon inventory database for construction materials will be a good reference for property developers, architects, engineers, contractors, procurement officers, and material suppliers to optimize their design, construction, and logistic approaches for GHG emission reduction. The content of this paper is organized as follow: Section 2 describes the methodology framework adopted in this project with consideration of local factors; Section 3 provides an illustrative example about the calculation of embodied carbon; Section 4 concludes the paper and discusses the potential application of the ECO-CM database. 2. METHODOLOGY The LCA methodology framework in this project is developed with reference to the stages and requirements described by ISO 14040:2006 (ISO, 2006), ISO 14044:2006 (ISO, 2006) and Publicly Available Specification (PAS) 2050:2008 (defra, 2008). As 3

210 shown in Figure 1, the methodology framework consists of four main stages: (1) background study, (2) system boundary setting, (3) life cycle inventory analysis (LCI), and (4) result analysis and reporting. Figure 1: Methodology Framework for Life Cycle Carbon Measurement 2.1. BACKGROUND STUDY The purpose of background study is to ascertain the main features of a material including the characteristics, classification, manufacturing process and product market share. Literature review for material classification refers to international/regional specifications (e.g. ISO, The American Society for Testing and Materials (ASTM)) and existing databases such as ICE and Ecoinvent. Material classification differentiates the materials for construction purpose and non-construction purposes. Following the material classification, the market share information for the construction materials will be collected and the manufacturing process will be investigated. Finally, with respect to the material manufacturing process, the GHG emission sources are identified stage by stage from raw material extraction to final product transport DETERMINATION OF SYSTEM BOUNDARY System boundary separates the internal components of a construction material system from externalities. The purpose of system boundary setting is to determine the scope of study. As shown in Figure 2, the material system is divided into a series of unit stages including raw material extraction, product manufacture, final product transport, material use, disposal and recycling. Raw material extraction refers to Cradle, which means the start of a material life cycle. Correspondingly, material disposal refers to Grave, which means the end of a material life cycle. System boundary setting should cover a set of stages over the full material life cycle such as Cradle-to-Gate and Gate-to-Gate. The stages within the system boundary are the focus of the life cycle analysis. In ECO-CM, calculation of material embodied carbon is examined with 4

211 respect to the Cradle-to-Site life cycle, which covers raw material extraction to packing and shipping the final products. Figure 2. Different Life Cycle Boundary of a Product System 2.3. LIFE CYCLE INVENTORY ANALYSIS LCI involves creating and quantifying the relevant inputs and outputs of a material system during the Cradle-to-Site life cycle. The inputs refer to fossil fuel, electricity, raw materials while the outputs refer to emissions to air, discharge to water and soil, etc. In this project, the inputs and outputs are collected from material manufacturers and vendors through questionnaire survey. Some common questions are raw material usage, transportation means, location of the suppliers, consumption of fuel and electricity, etc. Following the data collection, first-hand data from material manufacturers and vendors are used to calculate the embodied carbon in the Cradle-to-Site life cycle boundary. The calculation of embodied carbon is consistent with the standard GHG auditing guidelines, such as International Panel on Climate Change Guidelines for National Greenhouse Gas Inventories (IPCC, 2006) and the Greenhouse Gas Protocol (WRI and WBCSB, 2011). Some calculation considerations are the embodied carbon of raw materials, the emissions from energy consumption, as well as the emissions from final product transport. In some special cases, non-energy emission should be considered, such as the CO 2 emitted during raw materials calcination in the process of manufacturing cement RESULT ANALYSIS AND REPORTING The final stage of the methodology framework is to analyse and report the material embodied carbon from LCI. For example, result analysis can identify and compare the proportion of gaseous emissions in different stages during the material life cycle. In this way, people can identify the stages that emit the largest amount of GHG and the optimal solutions of minimising the quantity of gaseous emissions. On the basis of the analysis results, the reporting stage should provide some key findings and recommendations for material development and improvement. 5

212 3. ILLUSTRATIVE EXAMPLE OF PORTLAND CEMENT In this section, an illustrative example is provided to demonstrate the calculation of embodied carbon of cement. First of all, the background study investigates the current cement market in Hong Kong. The system boundary of Portland cement includes raw material extraction and quarrying, raw material transport, cement manufacturing, and final product transport. After extraction and quarrying, the raw materials, which are clay, limestone, iron ore and sand, are transported to cement factory. The raw materials are grinded to fine powder and are mixed preparing for calcination. Under a temperature of , the clinker is produced and CO 2 is emitted. The last phase is the transport of the cement product to the construction sites. The accuracy of the GHG emission calculation depends on the availability and quality of the data collected from the manufacturers. Therefore, a bilingual questionnaire (English and Traditional Chinese) for cement manufacturers was designed. The questionnaire contains 11 parts which are consistent with the GHG emission sources during the material life cycle. The GHG emissions calculation method involved in this study follows the IPCC Guidelines for National Greenhouse Gas Inventories. After GHG emission calculation, revision of the questionnaire and verification of the data were needed for keeping results accuracy and data consistency. Table 2: Results of CO 2 -e for Each Part of Cement Life Cycle (1) Upstream kg CO 2 -e/kg kg CO Percentage 2 -e/kg material clinker cement Percentage Limestone Sand Clay Iron ore Coal Total CO 2 -e (1) % % (2) Concrete kg CO 2 -e/kg kg CO Percentage 2 -e/kg batching clinker cement Percentage Calcination % % Coal combustion % % Electricity consumption % % Imported clinker NA % Total CO 2 -e (2) % % (3) Transport kg CO 2 -e/kg kg CO Percentage 2 -e/kg clinker cement Percentage Limestone Sand Clay Iron ore Imported clinker Coal Cement Total CO 2 -e (3) % % Total CO 2 -e % % 6

213 The calculation results of the illustrative example are summarized in Table 2. As shown in Table 2, the cement manufacture process emits kg CO 2 -e/ kg cement and accounts for the highest contribution (90.89%) of the total GHG emission during the cement life cycle. The following contributor is raw material and the final product transport, which is 7.28% of the total GHG emission. On the other hand, raw material extraction contributes the least CO 2 emission due to much less energy consumption compared with the manufacturing process. Calcination of carbonates is the major source of CO 2 emission, which accounts for 47.33%. Coal combustion, accounting for 29.90% of total emissions, is another important source. Moreover, CO 2 emission caused by electricity consumption and import clinker account for 7.92% and 5.74% of CO 2 emission of manufacturing process, respectively. The total GHG emission of the illustrative example is 1.01 kg CO 2 -e/ kg cement. The results from different sources will be aggregated for each construction material in the ECO-CM database. The results of calculation of each construction material could be directly used to support the environmental performance assessment of a building according to recent standardization work. For other construction materials involved in this study, such as concrete, glass, steel, aluminium, and ceramics, the embodied carbon will be calculated using similar methodology as described in cement study. Finally, the result of GHG emissions calculation over Cradle-to-Site, Cradle-to-Gate and Gate-to- Gate life cycles will be summarized for developing the ECO-CM database. 4. DISCUSSION Unlike ICE and Ecoinvent which use the Cradle-to-Gate material life cycle, ECO-CM considers the product life cycle from raw material extraction (Cradle) to transportation of the construction material (Site). Moreover, in ECO-CM, first hand data from material manufacturers and vendors are collected and used to calculate the material embodied carbon. Therefore, the life cycle inventory data from ECO-CM provide a more accurate and local specific estimate of GHG emission from construction materials. ECO-CM provides several benefits to the local construction industry: (1) Green construction materials selection: In Hong Kong, there is a trend to consider the utilization of green construction materials in the green building evaluation system (i.e. BEAM Plus). The evaluation system encourages contractors to utilize green construction materials during the building construction stage. Under such circumstances, the ECO-CM database provides a benchmark for evaluation and selection of the green construction materials. (2) Prediction of GHG emission: The ECO-CM provides a guideline for prediction of GHG emission in material production as well as the GHG emission embodied in buildings and infrastructures. For example, cement manufacturers can use the gate-togate embodied carbon to estimate the GHG emission in cement production. For a building project, the Cradle-to-Site embodied carbon of each material can be applied to calculate the embodied carbon of a building. (3) Development of green construction materials: The ECO-CM provides the amount of GHG emitted in different stages during the material life cycle. The information can help identify the stage that incurs serious contaminations and the optimal solution in reducing the GHG emissions. In this way, the environmental performance of a material can be improved because the gaseous emissions during the material life cycle are reduced. 7

214 REFERENCES Cornish, A., Larson, J. et al. January Hong Kong Ecological Footprint Report 2010:Report to the World Wildlife Fund (WWF). Hong Kong. defra PAS 2050: Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Service. UK. International Organization for Standardization ISO 14040:2006 Environmental Management Life Cycle Assessment Principles and Framework. Switzerland. International Organization for Standardization ISO 14044:2006 Environmental Management -Life Cycle Assessment - Requirements and Guidelines. Switzerland. International Panel on Climate Change Guidelines for National Greenhouse Gas Inventories. Japan. United Nations Framework Convention on Climate Change (UNFCCC). November, Report of the Conference of the Parties on its sixteenth session, held in Cancun from 29 November to 10 December Cancun Climate Change Conference. Cancun. WRI and WBCSB Greenhouse Gas Protocol - Product Life Cycle Accounting and Reporting Standard.US. 8

215 BASELINE CARBON ASSESSMENT FOR THE CONSTRUCTION PROCESS OF PUBLIC AND PRIVATE PROJECTS IN HONG KONG Bruce W.H. Chong 1, Wilfred Lau & Vincent Cheng Ove Arup & Partners, Hong Kong 1 Corresponding Author bruce.chong@arup.com / bruce.chong@hku.hk, Tel: (852) , Fax: (852)

216 CARBON FOOTPRINT IN CONSTRUCTION ABSTRACT Although the construction industry takes up a major portion of the economic activities (3.4% of total GDP in 2011) in Hong Kong, construction emissions are an information gap in the construction life cycle. In the literature, a number of life cycle energy, energy consumption and embodied carbon studies have been carried out. Nevertheless, around the world, the number of study looking into the overall green house gas impact of the whole construction sector to the society is very limited. Therefore, a study is conducted to focus on energy use and emissions associated with the construction process itself, i.e. at construction sites and from related activities. The key objectives of this study are to (i) define the scope and methodology of carbon assessment specific to the local context; (ii) quantify carbon footprint for the Hong Kong construction sector; and (iii) identify key influencing construction activities and emission reduction opportunities. It is found that the construction industry is responsible for around 1.65% of Hong Kong s total GHG emissions, representation about 700,000 tonnes of carbon equivalent. Keywords: CARBON; CARBON APPRAISAL; CONSTRUCTION. 1. INTRODUCTION Over the past decade, several studies related to low carbon construction have been conducted in Hong Kong. For example, the Electrical and Mechanical Services Department (EMSD) conducted a Life Cycle Energy Analysis (LCEA) of Building Construction assessment to develop an assessment tool with model and data that appraises life cycle cost (LCC) and the life cycle performance of building materials and components (EMSD, 2002); the Hong Kong Housing Authority (HA) has also developed an in-house database, technical guidelines and procurement strategy of their major building materials in the perspective of life cycle analysis (LCA) and LCC (HA, 2005); the EMSD and the Environmental Protection Department issued a Guidelines to account for and report on greenhouse gas emissions and removals for buildings (commercial, residential or institutional purposes) in Hong Kong (EMSD, 2010) covering the significant types of greenhouse gas (GHG) emissions commonly found in commercial buildings; the University of Hong Kong (HKU) and Construction Industry Council (CIC) have developed a carbon labeling scheme (including carbon assessment methodology, labeling framework and benchmarking mechanism) for construction materials; a green building product labeling scheme in Hong Kong has also been formulated by the HKU and Hong Kong Green Building Council (HKGBC). Apart from the above projects, there have been studies on emissions data at the stages of extraction, manufacturing and operation. Nevertheless, there has not been a carbon assessment looking into the emission of the whole construction sector during the construction stage in Hong Kong. Therefore, the information gap by focusing on energy use and emissions associated with the construction process itself, i.e. at construction sites and from related activities is yet to be filled (see Figure 1). 2

217 Emissions Materials extraction or product manufacture Embodied Energy In Use Operation Energy Missing Data: Construction Emissions Figure 1 Construction Emissions Information Gap in the Construction Life Cycle With a view to fill in this gap, Ove Arup & Partners HK Ltd. (Arup) has undertaken a study 2 to fill the information gap by focusing on energy use and emissions associated with the construction process itself, i.e. at construction sites and from related activities. The key objectives of this study are to (1) define the scope and methodology of carbon assessment specific to the local context; (2) quantify carbon footprint for the Hong Kong construction sector; and (3) identify key influencing construction activities and emission reduction opportunities. 2. SCOPE AND BOUNDARY 2.1. EXISTING GHG ASSESSMENT PROTOCOLS Broadly speaking, there are two approaches to greenhouse gas accounting which align with the two ISO standards for greenhouse gas accounting. One for organizational accounting (ISO :2006 Specification with guidance at the organization level for quantification and reporting of greenhouse gases emissions and removals: and another project or product accounting (ISO :2006 Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements). However, both organisational and project/product accounting approach are not directly relevant to this study because the construction sector is not a single organisational entity for which emissions sources can be allocated into Scope 1, 2 and 3. For example, it may be clear that constructionrelated freight is part of the construction process, but it may be considered as Scope 3 for a main contractor which can be excluded in the calculation, as this function is subcontracted to another organisation SCOPE OF CONSTRUCTION ACTIVITIES As there is currently no GHG protocol for the construction sector or a universal definition of construction activities, the scope of this study was defined based on a review of major international GHG accounting protocols and standards, a literature review of the definition of the construction sector in different countries, and stakeholder engagement through meetings with government departments, developers, contractors and professional institutions. Through a combination of these channels, we have developed four criteria to classify each construction activity to either target scope, or out of scope (see Table 1). For those construction process classifed as target scope, they will be included in the carbon calculation; while for those classified as out of scope, they will not be calculated. 2 This study was commissioned by the Development Bureau of the Hong Kong Government 3

218 Table 1 Summary of Scope of Construction Activities Activities Construction activities Criteria (See Note) Extent of control by main contractor On-site activities Project based Data availability Scope Construction works Yes Direct or partial Yes Yes Target Site offices Yes Direct Yes Yes Target Transporting materials to site Transportation Yes Direct or partial Yes Yes Target Waste removal Yes Direct or partial Yes Yes Target Employee commuting (by direct site vehicle) Employee commuting (by other means of transport)? Direct or partial Yes Yes Target?? Yes Yes Target Others Off-site assembly? Direct or partial?? Out of Scope Corporate offices? Direct or partial No No Out of Scope Consolidation Centre? Direct or partial No No Out of Scope Extraction and production of materials, No No No No Out of Scope products and plant Off site waste, soil and waste water treatment No No No No Out of Scope Water extraction and treatment No No No No Out of Scope Note: Criteria 1: Whether the processes is commonly considered as construction activities Criterion 2: Extent of control by Main Contractor. Direct control means that a party is both financially and operationally controlled by the Main Contractor while partial control means that a party is either financially or operationally controlled by the Main Contractor. Criterion 3: Practicality of acquiring data at project level. Criterion 4: Availability of data for each activity 2.3. MEASUREMENT PERIOD AND BOUNDARY This study selected 2010 as the baseline year since it is the most recent year that can provide the largest amount of available and reliable emissions data at the time of this study. In terms of territorial boundary, this study accounts for construction emissions sources within the Hong Kong territorial boundary, same as the GHG accounting of EPD which follows the IPCC GHG inventory protocol (IPCC, 2006). It implies that imports and exports of construction materials are out of scope. All emissions from fuels for international aviation and marine travel and multilateral operations are excluded from the total domestic inventory. This study includes only domestic travel, which is defined as all movements within the boundary of Hong Kong. For example, if any 4

219 materials imported from Shenzhen China are directly transported to Hong Kong by land, transport emissions due to the distance between Shenzhen and the Hong Kong- Shenzhen border are not counted. Emissions would only be counted when the materials are within Hong Kong, that is, when the transporting truck has crossed the Hong Kong-Shenzhen border and entered the territory of Hong Kong. In terms of GHG in this study, we focused on the GHGs associated with construction and so, only CO 2, CH 4 and N 2 O were included DATA COLLECTION AND SAMPLING A data collection form was prepared on the basis of the scope of construction activities (as discussed in 2.3) and various types of data to collect information of each individual construction project, including activity data, physical units of fuel use, category and fiscal data of the project. Projects under four categories including domestic, nondomestic (ND), civil & infrastructure (C&I), and maintenance & refurbishment (M&I), following the same classification of the construction output data measured by the Census and Statistical Department (C&SD, 2011), were collected from the contractors. We received 85 returned samples out of 752 projects for the first three categories in 2010 (domestic, ND and C&I), the return rate is 11.3%. The total number of returned samples for all categories is 128, contributed from more than sixty contractors. Table 2 Category Summary of Sample Collection Total no. of projects in 2010 No. of sampled projects in public sector No. of sampled projects in private sector Total Returned samples (%) Domestic Buildings (9%) Non-domestic Buildings (8%) Civil & Infrastructure (17%) Maintenance and No record from 43 (Not refurbishment C&SD Applicable) (M&R) Total (Site & Nonsite Projects) (Not Applicable) 3. ASSESSMENT METHODOLOGY The calculation of carbon emissions comprised three levels project, category and sector. The project level refers to the individual construction projects sampled, the category level refers to the four categories of domestic, non-domestic, C&I and M&R and the sector level refers to the whole construction sector. The overall approach of calculating emission intensity at different levels follows the following steps: 5

220 Project Level Category Level Sectoral Level Sustainable Building 2013 Hong Kong Regional Conference Calculate the total emissions of the aggregate Emissions of Construction Sector = Summation of Emissions of each Category Calculate the total emissions of each category Emissions of each category = Activity of each category x Emissions Intensity of each category Calculate the average emissions intensity (tonnes of CO2e emission per HK$ million) of each category (domestic / non-domestic / civil & infrastructure / maintenance & refurbishment) Determine the emissions intensity (tonnes of CO2e emission per HK$ million) of each project Sample data of activities (utilities, materials transport, waste) and value of contractors work in HK$ million in each project Figure 2 Overall Approach to Calculating Emissions 4. ASSESSMENT METHODOLOGY Table 3 summarises the emission data of the contruction industry. Overall, the emission intensity of the whole construction is 6.36tCO 2 e/hk$million, representing 1.65% of the emission of Hong Kong. The C&I category has the highest emission intensity and the non-domestic category the lowest. Although the C&I category has the highest emission intensity, the M&R category is responsible for roughly half of the total emissions. The non-domestic category contributes the least to overall emissions. The M&R category gives about half of the overall construction emission, which is similar to its contribution to the GVCW 3 (45%) in The other half emission are from the total of other three categories (Domestic, Non-domestic and C&I represent the site projects). Among all categories, the non-domestic category gives the least amount of emissions, same as its least contribution to the GVCW (16%). Table 3 Emission of Hong Kong Construction Sector Category GVCW in Emission Intensity Emissions 2010 (HK$ (tco million) 2 e/hk$ million) (tco 2 e) Domestic 22,588 (20%) Non-domestic 18,251 (16%) C&I 20,683 (19%) M&R 49,752 (45%) % of overall emissions , , , , Overall 111, , Figure 3 shows the emissions results broken down by construction activity. It shows that in Hong Kong, on-site activities are the largest contributor to emissions from the construction industry. In the domestic and the non-domestic category, on-site activities 3 The Report on the Quarterly Survey of Construction Output issued by the Census and Statistical Department (CSD) provides information on the gross value of construction value (GVCW) performed by construction establishment 6

221 are the largest contributor to emissions, followed by staff commute, material transport and waste disposal. In the C&I category, on-site activities are the largest contributor to emissions, followed by waste disposal, material transport and staff commute. In the M&R category, on-site activities remain the largest contributor to emissions but the corresponding proportion is much less than that in the other three categories. Waste disposal is the second largest contributor, followed by staff commute and material transport. Overall, on-site activities (which comprise site office and construction works) take up more than 80% of emissions, followed by waste disposal, staff commute and material transport. 100% 90% 80% 70% 11% 0.2% 6% 6% 9% 0.1% 3% 7% 1% 4% 5% 2% 26% 0.4% 3% 4% 5% 2% 5% 4% 15% 5% 5% 10% 60% 50% 32% 40% 77% 81% 88% 84% 30% 67% 20% 34% 10% 0% Domestic Non-domestic C&I M&R Total (HK) Total (UK) On-site activities Material transport Waste disposal under CWDCS Alt. waste disposal Staff commute Off-site assembly Corporate office Business travel Figure 3 Results by Construction Activity As on-site activities take up more than 80% of total emissions, on-site emissions were broken down for further analysis. Figure 4 displays the results for emissions of on-site activities from site office and construction works. In the domestic and the non-domestic category, superstructure works account for the most of on-site emissions (68% for nondomestic and 76% for non-domestic), followed by piling and related foundation works and site formation and clearance. Site office accounts for the least in both categories. In the C&I category, emissions are somewhat evenly split between superstructure works and piling and related foundation works, which together account for close to 70% of on-site emissions. Site formation takes up about 18% of the on-site emissions, which is the highest among all categories. Site office takes up about 14% emission, which is higher than the domestic and the non-domestic category. In the M&R category, construction works (i.e. Others 4) take up 70% of on-site emissions and site office 30%. Emission portion from the site office is the highest among all categories. Overall, superstructure works account for almost half of on-site emissions (45%), followed by piling and related foundation works (29%) and site formation and clearance (14%). In 4 Note that Others in the M&R category represent construction works as well, but are so named as it is not possible for M&R contractors to break down their works into activities such as piling and site formation. Due to the diverse nature of M&R projects, construction works may be repainting, redecoration, electrical and mechanical repair or maintenance. 7

222 general, construction works take up almost 90% of on-site emission and site office the remaining. 100% 1% 90% 80% 32% 45% 70% 60% 68% 76% 70% 50% 36% 40% 29% 30% 20% 10% 0% 20% 18% 12% 14% 30% 8% 7% 14% 11% 4% 5% Domestic Non-domestic C&I M&R Total Site office Site formation and clearance Piling and related foundation works Superstructure works Others Figure 4 Emissions from On-Site Activities (by site office and construction works) In terms of energy sources, electricity and diesel together account for 98% of on-site emissions. Emissions from electricity use exceed those from diesel use in the domestic and the non-domestic category, with electricity accounting for around 60% of emissions and diesel 40%. Emissions from diesel use exceed those from electricity consumption in the C&I category, with diesel accounting for around 60% of emissions and electricity 40%. In the M&R category, emissions from electricity and petrol consumption take up the majority. Emissions from diesel account for only around one-fifth of emissions. Overall, diesel use takes up more than half of on-site emissions and electricity use the remaining 46%. Emissions from other sources are negligible. Table 4 Summary of onsite emissions (by fuel) Category Electricity Diesel Gasoline / LPG Domestic 62.9% 36% 0.2% Non-domestic 58.2% 41.4% - C&I 38.5% 59.8% 1.0% M&R 44.3% 22.3% 31.7% Overall 46.4% 51.8% 1.2% 5. WAY FORWARD On the basis of the results, we recommend that several key tasks should be conducted: (i) Developing comprehensive low-carbon construction action plan for implementation; (ii) Developing carbon report framework and tools; (iii) 8

223 Benchmarking methodology and best practice guideline; and (iv) Setting emission reduction target. The first task concerns with an an overall low-carbon master-plan for the whole construction industry with implementation strategy with initiatives, timeline, responsible parties, funding arrangement, etc. The second task refers to setting benchmarks for energy consumption and carbon performance since there is a need for a complete and consistent carbon appraisal for construction projects through a formal carbon reporting framework. Currently, although some companies have their own organisational carbon accounts, which may capture project-related carbon, there is no mechanism for contractors to provide voluntary energy and fuel use data for completed projects. A uniformly accepted reporting framework with guidance and tools for the collection of data and assessment of emissions from construction sites should be developed and initiated. The third task is to develop performance benchmarks to identify effective implementation of emissions reduction measures. For example, regarding fuel use benchmark, it is suggested developing local energy label or green label for different types of construction equipment and materials. The fourth recommendation is to develop set realistic targets for reduction, and also understand its overall impact on overall emissions reduction strategy of Hong Kong in the coming years. In order to realize all these, it is necessary to engage contractors through initiatives or incentives, request them to submit carbon reporting periodically and set carbon reduction targets by following the best practice benchmark. As such, for each project, the amount of carbon reduction can be obtained, and the overall total savings on carbon and cost within a given period can be estimated. 6. SUMMARY This study was undertaken to fill the information gap in the construction life cycle, which is the first in Asia to adopt to quantify emissions from the construction industry. It has quantified that the carbon emissions from the construction sector in Hong Kong is about 1.65%. In terms of reduction strategy, the key is to improve efficiency of on-site activities (comprising site office and construction work) and reduce diesel use, which represents 84% and 54% of overall emissions 7. References C&SD, Report on the Quarterly Survey of Construction Output, Census and Statistical Department, fourth quarter, 2011 EMSD, Energy Analysis and Saving Technologies: Life Cycle Energy Analysis (LCEA) of Building Construction, 2002 EMSD & ESD, Guidelines to Account for and Report on Greenhouse Gas Emissions and Removals for Buildings (Commercial, Residential or Institutional Purposes) in Hong Kong, 2010 Edition. HA, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) study of building materials and components, Housing Authority, 2005 IPCC, Intergovernmental Panel on Climate Change, Guidelines for National Greenhouse Gas Inventories,

224 ASSESSING CARBON FOOTPRINTS OF ZERO CARBON BUILDINGS Dr. Sam C. M. Hui Department of Mechanical Engineering, The University of Hong Kong Pokfulam Road, Hong Kong 1

225 ASSESSING CARBON FOOTPRINTS OF ZERO CARBON BUILDINGS ABSTRACT Building sector is a major contributor of greenhouse gas and carbon emissions in the world. Nowadays, many countries are developing policies and measures to promote zero or low carbon buildings with the aim to reduce the carbon emissions and ecological footprints. However, as a clear definition of zero carbon building (ZCB) and effective evaluation methods for building s carbon footprints are not available, people are often confused about the real performance of ZCBs and the strategy to reduce the carbon footprints. This research study investigates the meaning of ZCBs and develops assessment methods for evaluating their carbon footprints. The definition of ZCB and the related concepts are described. The meaning of footprints and the rationale for using carbon footprints as indicators to measure sustainability are presented. It is found that the footprint-based assessment requires a clear understanding of emissions categories, assessment boundaries and carbon accounting principles. The assessment outcome is depending on the problem definition and interpretation method. The main influences on the carbon footprints include building functions, site conditions, energy and carbon intensity of the building systems and components. In order to develop systematic methods for assessing the carbon footprints, a holistic approach to carbon accounting and footprint calculation is needed. When applying the concepts to assess the buildings in densely populated cities like Hong Kong, some key factors for urban density and sustainability should be considered, such as transportation strategy, urban form and typology. Keywords: Carbon emissions and reduction; Carbon footprints; Hong Kong; Urban cities; Zero carbon building. 1. INTRODUCTION To achieve sustainability and combat the climate change issue, developing a low carbon society is a global trend (ADEME, 2010; DCLG, 2007; NIES, 2009; Zuo, et al, 2012). Low or zero carbon design is essential to the carbon reduction target (Brown, 2010). Among all sectors, buildings are one of the largest sources of carbon dioxide and greenhouse gas (GHG) emissions as these gases are the by-product of electricity consumption which is used extensively in buildings. The building sector also presents the most cost effective opportunities for GHG reductions (IPCC, 2007). In recent years many countries are developing policies and measures to promote zero or low carbon buildings with the aim to reduce the carbon emissions and ecological footprints (ASBEC, 2011). Energy efficiency and carbon emission reduction in buildings have become an important trend in the world (Boake, 2008; Hui, 2012; Loper, et al., 2008). However, as a clear definition of zero carbon building (ZCB) and effective evaluation methods for building s carbon footprints are not available, people are often confused about the real performance of ZCBs and the strategy to reduce the carbon footprints (Hui, 2010). This research study investigates the meaning of ZCBs and develops assessment methods for evaluating their carbon footprints. The definition of ZCB and the related concepts are described. The meaning of footprints and the rationale for using carbon footprints as indicators to measure sustainability are presented. The current situation in Hong Kong and key factors for urban density and sustainability are discussed. 2

226 2. ZERO CARBON BUILDINGS The terms zero energy, zero carbon or zero emission are applied to buildings that use renewable energy sources on-site to generate energy for their operation, so that over a year the net amount of energy generated on-site equals the net amount of energy required by the building. Studying the definitions of the terms associated with ZCB is important because the meaning of ZCB and the related concepts are often expressed unclearly and are sometimes misunderstood (Hui, 2010) ZERO ENERGY AND ZERO CARBON BUILDINGS Zero energy building (ZEB) is often used in conjunction with ZCB. ZEB can be defined as a building that produces as much energy on-site as it consumes on an annual basis. Torcellini, et al. (2006) provided four definitions of ZEB: net zero site energy, net zero source energy, net zero energy costs, and net zero energy emissions. A classification system based on renewable energy supply options is also used to distinguish different types of ZEB. Table 1 shows a summary of the terms and definitions. building (off-site ZEB) Net zero source/primary energy building (source ZEB) Net zero energy cost building (cost ZEB) Net zero energy emissions building, zero carbon building (ZCB), zero emission building Table 1: Terms and definitions of ZEB and ZCB Terms Definitions/Meanings Zero energy building (ZEB) A building that produces as much energy on-site as it consumes or net zero energy building on an annual basis (NZEB) Net zero site energy building Amount of energy provided by on-site renewable energy (site ZEB) sources is equal to the amount of energy used by the building Net off-site zero energy Similar to previous one, but consider purchasing of energy offsite from 100% renewable energy sources It produces as much energy as it uses in a year, when accounted for the source. For electricity, only around 35% of the energy used in a fossil fuel power plant is converted to useful electricity and delivered. Site-to-source conversion multipliers are used to calculate a building s total source energy The cost of purchasing energy is balanced by income from sales of electricity to the grid of electricity generated on-site The carbon emissions generated from the on-site or off-site fossil fuel use are balanced by the amount of on-site renewable energy production In recent years, many researchers and governments have investigated the definitions of ZEB and ZCB with the goal to develop an internationally agreed and consistent definition (ASBEC, 2011; DCLG, 2008; ECEEE, 2009; Fulcrum, 2009; Marszal, et al., 2011; Sartori, Napolitano and Voss, 2012; UK-GBC, 2008). It is believed that promotion of ZEB and ZCB can help control carbon emissions and improve building performance. In general, ZEB design differs from ZCB design in that it is more concerned with the reduction of the operating energy requirements for a building, focusing on the eventual use of zero fossil energy. By using renewable and low-carbon energy sources, it is possible to offset or balance the carbon emissions produced from the building BALANCING CARBON CONCEPT Figure 1 shows the balancing carbon concept for ZCB. To develop a systematic methodology for studying ZEB/ZCB, Sartori, Napolitano and Voss (2012) identified two major types of balance, namely the import/export balance and the load/generation balance, which are suitable for defining ZCB and ZEB, respectively. 3

227 Balancing Carbon Operating energy of building Embodied carbon in building materials People, use and transportation Zero 0 On-site renewable and generation Off-site renewable, generation and supply Other purchased carbon offsets Figure 1: Balancing carbon concept for ZCB After studying the definitions and calculation methodologies of ZEB, Marszal, et al. (2011) identified the following sources of difference between definitions: (a) The metric of the balance (e.g. primary energy, final energy, carbon emission) (b) The balancing period (monthly, seasonal, operation year, life cycle) (c) The type of energy use included in the balance (e.g. HVAC, lighting, appliances) (d) The type of energy balance (import/export and load/generation) (e) The accepted renewable energy supply options (f) The connection to the energy infrastructure (grid connected or standalone) (g) Other requirements relating to energy efficiency, the indoor climate and buildinggrid interaction DEFINITIONS OF ZCB In Australia, ASBEC (2011) has tried to develop a suitable definition for ZCB to assist stakeholders to progress towards zero emissions. Their definition is given below. A zero carbon building is one that has no net annual Scope 1 and 2 emissions from operation of building incorporated services. Building-incorporated services include all energy demands or sources that are part of the building fabric at the time of delivery, such as the thermal envelope, water heater, built-in cooking appliances, fixed lighting, shared infrastructure and installed renewable energy generation Zero carbon buildings must meet specified standards for energy efficiency and onsite generation Compliance is based on modelling or monitoring of greenhouse gas emissions in kg CO 2- e/m 2 /yr. Some variations of ZCB were identified by ASBEC (2011) as shown in Table 2. The scope and nature of the ZCB must be clearly defined to avoid misunderstanding. Sometimes, for the sake of simplicity, the definition of ZEB/ZCB might include only the balance between daily operating energy of the building and the renewable energy generation. Another method of zero carbon calculation is to consider building structure, building materials and equipment, production, transportation, construction process, etc. in order to indicate the embodied energy or embodied carbon emissions. 4

228 Standard Sustainable Building 2013 Hong Kong Regional Conference Table 2: Variations of ZCB [adapted from ASBEC (2011)] Zero carbon occupied building Include occupant emissions Zero carbon embodied building Include embodied emissions Zero carbon life-cycle building Include all emission sources in the building life cycle Autonomous zero carbon building No grid connection Carbon positive building Achieves less than zero emissions A more stringent and broader definition would consider the whole life cycle, from planning and design, building materials production, materials transportation, construction process, daily building operations, renovation and maintenance repairs, waste disposal. However, the calculations for this zero carbon life-cycle building are very difficult and complicated (Hernandez and Kenny, 2010) EMISSION REDUCTION OPTIONS One critical issue to consider for ZCB is the allowable options for emission reduction. Figure 2 shows the options proposed by ASBEC (2011) which include both on-site and off-site methods for renewable/low carbon energy sources. It is a three-tier approach that includes a target for energy efficiency of the building design and construction as a priority. In addition, there is a target for on-site low or zero carbon energy generation. The third tier includes off-site solutions which should only be considered after maximising the previous two tiers. 3a: Off-site generation 3b: Off-site supply e.g. Green Power 3. Off-site renewable / low carbon energy 2. On-site renewable / low carbon energy 1. Energy Efficiency 2a: In building footprint 2b: On land title 2c: Private wire 2d: On-site generation from off-site resources Figure 2: Allowable emission reduction options for ZCB [adapted from ASBEC (2011)] From a holistic life-cycle point of view, a building is considered sustainable in the model if by the end of its expected lifetime the total amount of carbon emissions are completely offset (Bendewald and Zhai, 2013). In general, zero carbon demands a numerical assessment and validation of the building design. ZCB compliance requires designers to numerically validate the effectiveness of their approaches; there are various means by which this can be done, as well as relative scales of the problem that might be examined (Boake, 2008). Therefore, it is important to clearly describe the calculation methods and assumptions when assessing ZCB. 3. ASSESSMENT OF CARBON FOOTPRINTS Carbon is frequently used as shorthand for either carbon dioxide (CO 2 ) or carbon dioxide equivalents (CO 2 -e), which includes both CO 2 and other gases with significant global warming potential (GWP). A footprint is a quantitative measurement indicating the appropriation of natural resources by humans; it describes how human activities can impose different types of burdens and impacts on global sustainability (Čuček, Klemeš and Kravanja, 2012). 5

229 Carbon footprint is a measurement of the exclusive direct (on-site, internal), and indirect (off-site, external, embodied, upstream, and downstream) CO 2 emissions of an activity, or over the life cycle of a product, measured in mass units. A process-oriented life-cycle carbon footprint analysis is an analytical tool that focuses attention on hot spots and inefficiencies over the entire life cycle, and provides a framework for tradeoffs and optimisation (Hernandez and Kenny, 2010) CARBON FOOTPRINT OF BUILDINGS The carbon footprint of a building is the total amount of CO 2 and other GHGs emitted over the life cycle of that building, expressed as kilograms of CO 2 equivalents (kg CO 2 - e). This includes all GHGs generated in the manufacture of the raw materials, construction of the building, transport of materials to the construction site, operation of the building, periodic refurbishment and replacement of materials, and end-of-life disposal of the building materials. Figure 3 shows a building s carbon footprint and its components. Most of the carbon footprint emissions for buildings come from indirect sources, i.e. fuel burned to produce electricity. Thus, the most effective way to decrease a carbon footprint is to either decrease the amount of energy needed for production or to decrease the dependence on carbon emitting fuels (Brown, 2010). Materials manufacturing Materials transport Demolition wastes transport Demolition wastes treatment Building construction Building operation Building renovation Electricity consumption On-site fuel consumption On-site waste water treatment On-site solid wastes treatment Industrial processes housed in the building De-construction Figure 3: Carbon footprint of a building and its components 3.2. MEASURING CARBON FOOTPRINTS A building s carbon footprint can be measured by undertaking a GHG emissions assessment or other calculative activities denoted as carbon accounting (Kennedy and Sgouridis, 2011). The following international standards are often applied for carbon footprint analysis using the principle of life-cycle assessment and GHG protocol. ISO 14040: Life Cycle Assessment - Principles and Framework BSI: PAS Specification for the Assessment of Life-Cycle GHG Emissions of Goods/Services WRI/WBCSD: Greenhouse Gas Protocol IPCC: 2006 Guidelines for National Greenhouse Gas Inventories 6

230 In Hong Kong, the government has prepared a set of carbon audit guidelines for buildings to report on GHG emissions and removal (EPD and EMSD, 2010). The assessment process focuses on the following aspects: Physical boundaries (usually the site boundaries of the building) Operational boundaries (to identify and classify the activities to determine the scope) o Scope 1 direct emissions and removals o Scope 2 energy indirect emissions o Scope 3 other indirect emissions Reporting period (usually one year) Collecting data and information to quantify the GHG performance The footprint-based assessment requires a clear understanding of emissions categories, assessment boundaries and carbon accounting principles (Čuček, Klemeš and Kravanja, 2012). The assessment outcome is depending on the problem definition and interpretation method. The main influences on the carbon footprints include building functions, site conditions, energy and carbon intensity of the building systems and components. In order to develop systematic methods for assessing the carbon footprints, a holistic approach to carbon accounting and footprint calculation is needed PRACTICAL ISSUES In practice, to assess the impact of buildings at the outset of a project, carbon estimators are used to provide a more general figure on project inputs like building size, primary structural system, and site conditions (Boake, 2008). As the project proceeds, carbon calculators that are more detailed and project-specific can be applied to assess the GHG emissions. All calculations need to examine the holistic aspects of the project in order to achieve a balance between carbon costs and the ability of the project to sequester carbon. Once the size of a carbon footprint is known, a strategy can be devised to reduce it. Table 3 shows four approaches to carbon reduction (ASBEC, 2011). Strictly zero carbon Net zero carbon Carbon neutral Low carbon Table 3: Different carbon reduction approaches No carbon is emitted within Scopes 1 and 2; neither balancing nor offsets are allowed. All carbon emissions within emissions Scope 1 are eliminated, and emissions within Scope 2 are balanced through export of low or zero carbon goods, internal or external sequestration, or import substitution of Scope 3 emissions. Any and all emissions for which the building is responsible under Scopes 1 and 2 can be managed through the purchase of offsets from third parties that lie outside the building s boundaries. Emissions under Scopes 1, 2 and 3 are reduced compared to a baseline. The reduction level is often not clearly specified. Performing the footprint analyses can be costly and time consuming. There are still many difficulties of implementing carbon debt accounting because the building development and construction activities are fragmented and very complicated. Chen, et al. (2011) have developed an evaluation framework for detailed life cycle carbon accounting of buildings based on multi-scale input-output analysis. Nine stages have been suggested including building construction, fitment, outdoor facility construction, transportation, operation, waste treatment, property management, demolition, and disposal for buildings. 7

231 4. DISCUSSIONS The act of carbon accounting is beginning to permeate a multitude of sectors. To systematically assess ZCB and develop effective strategies to decrease carbon footprints, it is essential to understand, quantify, and manage GHG emissions in a holistic and scientific way. It is also important to promote ZCB design strategies in the society to influence people for the cultural change and foster sustainable lifestyle SUITABLE CANDIDATES OF ZCB Brown (2010) pointed out that not all buildings are suitable candidates of ZCB. Adhikari, et al. (2012) raised some doubts about the affordability of ZCB/ZEB. Fong and Lee (2012) indicated that for subtropical cities like Hong Kong only the low energy design for buildings can be made possible, not the zero energy. It is commonly agreed that ZCB is an ideal goal at the present moment and cannot be realised in some situations. For example, given the high operating loads in facilities such as hospitals, hotels and laboratories, sufficient energy reductions may be impractical. Also, buildings in urban areas may have inadequate solar exposure due to shading by adjacent buildings and may not be able to achieve net zero energy. Furthermore, medium- to high-rise buildings will be problematic candidates given the high ratio of solar panel surface to total floor area required for ZCB/ZEB. It is believed that implementing ZCB/ZEB for low-rise residential buildings is more feasible (Fong and Lee, 2012). For commercial building developments, Zuo, et al. (2012) found that the lack of a clear definition of carbon neutral building presents a significant barrier and the key success factors include market demand, material selection, facility manager s knowledge, government support and leadership. Often, an exemplar project, such as a ZCB, can play a pivotal role in promoting cultural change. In order to speed up the transformation and achieve significant carbon reduction in the society, building refurbishment towards zero carbon is a critical aspect (Xing, Hewitt and Griffiths, 2011). Not only the development of new building design and planning, the existing building renovation should also attach importance to reduce GHG emissions GREEN BUILDING SUSTAINABILITY ASSESSMENTS Ng, Chen and Wong (2013) found that the current green building assessment schemes (such as BEAM Plus, BREEAM and LEED) focus primarily on operational carbon instead of the emissions generated throughout the entire building life cycle. Also, the baseline and benchmark for carbon evaluation vary significantly among the schemes. Bendewald and Zhai (2013) suggested that building sustainability assessment should evolve toward an absolute method using a credible science such as carrying capacity. Čuček, Klemeš and Kravanja (2012) believe that carbon footprints can be used as indicators to measure sustainability. However, the definition of a suitable sustainability metric for supporting objective sustainability assessments is still an open issue. As a type of environmental footprints, the carbon footprint has become an important environmental protection indicator in many disciplines. As described in Section 3, carbon footprint is an effective carbon accounting method for facilitating GHG trade-offs and optimisation in buildings. It is also a logical way to implement life cycle thinking into building planning and design. If a wider perspective is needed for the sustainability assessment, composite indicators including environmental, social, and economic footprints can also be developed to satisfy the need of multi-objective optimisation problems in the society (Čuček, Klemeš and Kravanja, 2012). 8

232 4.3. ZCB DESIGN STRATEGIES Hui (2012) has discussed the meaning of ZCB and indicated that construction innovation and environmental design are crucial for ZCB design. In many cases, ZCB design may be more complicated than the design of general buildings because of the need to study the specific location, requirements and actual energy usage to determine suitable arrangements for building energy efficiency and renewable/low-carbon energy. For many building categories, passive solar or low-energy design is often more costeffective than active systems like photovoltaics (PV). Common building energy efficiency measures include natural lighting, natural ventilation, proper building siting and massing, energy-efficient lighting, energy- efficient cooling and heating, energysaving office equipment and energy management. Table 4 shows a summary of the basic design strategies for ZCB. Table 4: Design strategies for ZCB At the outset, the building project should take into account building energy efficiency and use of renewable energy Select the appropriate building site; allow opportunity to apply renewable energy and to reduce transportation and food production needs Optimise passive design strategies to protect the natural and comfortable environment in order to reduce energy demand Conserve water and reduce the demand for hot water Appropriately select materials in order to reduce the environmental impacts Reduce energy use in all aspects of the building operation Consider building energy efficiency first before introducing renewable energy offsets Very often, the design of ZCB/ZEB requires analyses through dynamic building energy simulation and modelling in order to evaluate the design options and control strategies (Jankovic, 2012). As pointed out in Section 2.4, numerical assessment and calculations are needed for the validation of the ZCB design. Usually the information obtained from building energy simulation is critical for estimating and monitoring the energy use and related GHG emissions. It is also helpful to invoke life cycle assessment in the building development, design and management process (Hernandez and Kenny, 2010). 5. HONG KONG SITUATION Over 60% of the GHG emissions in Hong Kong come from buildings (Hui, 2012). When promoting ZCB and applying the carbon footprint concepts to assess the buildings in densely populated cities like Hong Kong, some key factors for urban density and sustainability should be considered carefully URBAN DENSITY Located in a sub-tropical hot and humid climate, Hong Kong is a densely populated city with many high-rise buildings. The land and space available for housing the population are very limited. Fortunately, Hong Kong has highly efficient mass transit and public transportation systems, which can greatly reduce the transport energy consumption and the associated GHG emissions from private vehicles. As mentioned in Section 4.1, high-rise buildings in urban areas are problematic candidates for ZCB. Therefore, more creative ideas and innovative technologies are needed to overcome the difficulties and constraints of designing ZCB or low energy building in such a high density urban city (Hui, 2001). The initial experience of exploring ZCB/ZEB in low-rise residential buildings in Hong Kong may be helpful too for developing the future ZCB design strategies (Fong and Lee, 2012). 9

233 If Hong Kong is to achieve environmentally friendly green building for the society, comprehensive urban planning and efficient high-performance building design are needed for controlling and reducing the GHG emissions in the high-rise, high-density building development and urban environment. By integrating sustainable transportation strategy, urban form and typology, it is possible to greatly improve the urban living environment and building performance. To achieve these objectives, it is important to develop a clear green building policy and foster life cycle thinking in the building development, design and management for the whole society. It is believed that carbon footprint analyses will be useful for developing effective assessment and guidance for the key decision makers COMMUNITY SUSTAINABILITY In Hong Kong, achieving ZCB on an individual basis is not easy (Civic Exchange, 2011). However, the high population densities and compact buildings of the city can provide opportunities for implementation of larger scale community based energy systems and cost-effective energy and utility supply arrangements (Hui, 2001). At the community level, if the infrastructure for the society and/or districts have been planned and designed to optimise the overall system efficiency and to reduce the carbon footprint, a zero carbon community could be established. For example, the use of district cooling system, waste-to-energy recovery approach, centralised solar thermal or other renewable energy systems, and community based greening and water recycling programmes can be applied to increase the overall resources efficiency and environmental performance, and to reduce the total GHG emissions of the community. By integrating architectural design, energy systems, community facilities, social development and environmental resources into coordinated comprehensive arrangements, the overall resources efficiency can be optimised. In fact, holistic zero carbon or carbon neutral design is looking to reduce the GHG emissions associated with all aspects of the project. The assessment of carbon footprint for such a project in Hong Kong will require consideration of the neighborhood and local or regional planning issues, as well as the human activities directly or indirectly affected by the sustainable community measures. 6. CONCLUSIONS Nowadays many countries in the world are developing zero- or low-carbon buildings in order to achieve GHG emission reduction and improve the awareness of environmental design. It is believed that ZCB/ZEB will lead the transition into low-carbon societies. In the near future, ZCB and low-carbon buildings will become a mainstream architecture. To overcome the barriers of ZCB, a clear definition and effective assessment methods are urgently needed. By examining the meaning of ZCB/ZEB and the rationale for using carbon footprints as indicators to measure sustainability, it is possible to improve the understanding of zero carbon life cycle design and develop clear scientific calculation methods for evaluating ZCB and other building projects. This research has discovered that using carbon footprint as the metrics for assessing ZCB can help decision makers to identify options for reducing and offsetting the GHG emissions. It should be noted that the market demand for ZCB/ZEB is still growing at an embryo stage. The progression of green/sustainable building design to include issues of carbon is highly complicated. At present, the application of carbon footprint and other footprintbased assessments are often hindered by limited data availability and uncertainty of data. More work is needed to develop reliable data and information for footprint or sustainability assessment of buildings. By developing integrated interdisciplinary ZCB 10

234 design and technology and properly integrating environmental, social and economic, considerations during decision making, it is hoped that an effective strategy can be built up for controlling GHG emissions and climate change. To conclude, zero carbon is a lifestyle, not a specific criterion. ZCB is produced using a variety of means to reduce the pollution, promote the rational use of waste, and encourage the use of environmentally clean energy sources to reduce GHG emissions. The ultimate aim is to achieve zero waste, zero energy and zero carbon in an ideal state. This spirit can be extended to zero-carbon transport, zero-carbon energy, zero carbon home, as well as zero-carbon city. REFERENCES ADEME, Roadmap for Positive-energy and Low-carbon Buildings and Building Clusters, French Environment & Energy Management Agency (ADEME), Angers Cedex, France. Adhikari, R. S., Aste, N., Del Pero, C. and Manfren, M., Net zero energy buildings: expense or investment?, Energy Procedia, 14 (2012): ASBEC, Defining Zero Emission Buildings, Australian Sustainable Built Environment Council (ASBEC), Sydney, Australia. Bendewald, M. and Zhai, Z., Using carrying capacity as a baseline for building sustainability assessment, Habitat International, 37 (2013): Boake, T., The leap to zero carbon and zero emissions: understanding how to go beyond existing sustainable design protocols, Journal of Green Building, 3 (4): Brown, H., Toward Zero-Carbon Buildings, The Post Carbon Reader Series: Cities, Towns, and Suburbs, Post Carbon Institute, Santa Rosa, CA. Chen, G. Q., Chen, H., Chen, Z. M., Zhang, B., Shao, L., Guo, S., Zhou, S. Y. and Jiang, M. M., Low-carbon building assessment and multi-scale input-output analysis, Communications in Nonlinear Science and Numerical Simulation, 16 (1): Civic Exchange, Less Than Zero? The Future for Buildings & Carbon Emissions, Forum Summary Report, 1 November 2011, Hong Kong. Čuček, L., Klemeš, J. J. and Kravanja, Z., A review of footprint analysis tools for monitoring impacts on sustainability, Journal of Cleaner Production, 34 (2012): DCLG, Definition of Zero Carbon Homes and Non-Domestic Buildings: Consultation, Department for Communities and Local Government (DCLG), London. DCLG, Building a Greener Future: Policy Statement, Department for Communities and Local Government (DCLG), London. ECEEE, Net Zero Energy Buildings: Definitions, Issues and Experience, European Council for an Energy Efficient Economy (ECEEE), Stockholm, Sweden. EPD and EMSD, Guidelines to Account for and Report on Greenhouse Gas Emissions and Removals for Buildings (Commercial, Residential or Institutional Purposes) in Hong Kong, 2010 Edition, Environmental Protection Department (EPD) and Electrical and Mechanical Services Department (EMSD), Hong Kong. Fong, K. F. and Lee, C. K., Towards net zero energy design for low-rise residential buildings in subtropical Hong Kong, Applied Energy, 93 (2012): Fulcrum, Fulcrum s Dream Definition of Zero Carbon Buildings, Fulcrum Consulting, London, 11

235 Hernandez, P. and Kenny, P., From net energy to zero energy buildings: Defining life cycle zero energy buildings (LC-ZEB), Energy and Buildings, 42 (6): Hui, S. C. M., The meaning of zero carbon buildings for construction innovation and environmental design, In Proceedings of the 2012 The 10th Cross Strait Two Coasts and Four Places Engineers (Hong Kong) Forum, November 2012, Hong Kong Productivity Council Building, Hong Kong, pp (in Chinese). Hui, S. C. M., Zero energy and zero carbon buildings: myths and facts, In Proceedings of the International Conference on Intelligent Systems, Structures and Facilities (ISSF2010): Intelligent Infrastructure and Buildings, 12 January 2010, Kowloon Shangri-la Hotel, Hong Kong, China, pp Hui, S. C. M., Low energy building design in high density urban cities, Renewable Energy, 24 (3-4): IPCC, Climate Change 2007: Synthesis Report, Intergovernmental Panel on Climate Change (IPCC), Geneva, Switzerland. Jankovic, L., Designing Zero Carbon Buildings Using Dynamic Simulation Methods, Earthscan, Abingdon, Oxon and New York, NY. Kennedy, S. and Sgouridis, S., Rigorous classification and carbon accounting principles for low and zero carbon cities, Energy Policy, 39 (9): Loper, J., et al., Reducing Carbon Dioxide Emissions through Improved Energy Efficiency in Buildings, Alliance to Save Energy, Washington DC. Marszal, A. J., Heiselberg, P., Bourrelle, J. S., Musall, E., Voss, K., Sartori, I. and Napolitano, A., Zero energy building a review of definitions and calculation methodologies, Energy and Buildings, 43 (4): Ng, T. S., Chen, Y. and Wong, J. M. W., Variability of building environmental assessment tools on evaluating carbon emissions, Environmental Impact Assessment Review, 38 (2013): NIES, Japan Roadmaps towards Low-Carbon Societies (LCSs), National Institute for Environmental Studies (NIES), Tsukuba, Ibaraki, Japan. Sartori, I., Napolitano, A. and Voss, K., Net zero energy buildings: A consistent definition framework, Energy and Buildings, 48 (2012): Torcellini, P., et al., Zero energy buildings: a critical look at the definition, In Proceedings of the 2006 ACEEE Summer Study on Energy Efficiency in Buildings, August 14-18, 2006, Pacific Grove, CA, 12 pp. UK-GBC, The Definition of Zero Carbon, Zero Carbon Task Group Report, UK Green Building Council (UK-GBC), London, available at Xing, Y., Hewitt, N. and Griffiths, P., Zero carbon buildings refurbishment A Hierarchical pathway, Renewable and Sustainable Energy Reviews, 15 (6): Zuo, J., Read, B., Pullen, S. and Shi, Q., Achieving carbon neutrality in commercial building developments Perceptions of the construction industry, Habitat International, 36 (2):

236 BENCHMARKING DEVELOPMENT OF THE SUSTAINABILITY OF HONG KONG BUILDINGS HKQAA SBI SUSTAINABLE BUILDING INDEX Connie Sham 1 and Caroline Ma Hong Kong Quality Assurance Agency, Hong Kong 1 Corresponding Author connie.sham@hkqaa.org, Tel: (852)

237 BENCHMARKING DEVELOPMENT OF THE SUSTAINABILITY OF HONG KONG BUILDINGS HKQAA SBI SUSTAINABLE BUILDING INDEX ABSTRACT This study presents the overview, development process and uniqueness of the benchmarking tool HKQAA Sustainable Building Index (HKQAA SBI), aiming to encourage the users of buildings, such as building owners or property managers to periodically evaluate buildings sustainability performance in terms of the triple bottom line principle, i.e. the environmental, social and economic aspects such that improvement opportunities can be identified for subsequent enhancement. Over the past decade, various green building rating systems or certification schemes were promoted across the globe. Notwithstanding the fact that the environmental performance of buildings becomes the core issue, however, the social and economic performance also plays an important role in measuring the sustainability performance of buildings. In addition, incidents related to ageing, maintenance, safety, security, quality and environmental issues of buildings in recent years has clearly signified the need of durable and sustainable buildings. In view of this, the Hong Kong Quality Assurance Agency (HKQAA) endeavours to develop a territory-wide benchmarking tool HKQAA SBI, which made reference to the latest international standards and best practices of the sustainability in building construction together with several key ISO standards. The HKQAA SBI is developed as a composite index of current sustainability performance along with thethroughout buildings life cycle;. tthe index encompasses 20 performance indicators (P.I.) for evaluating the performance of 10 core issues of the social, economic and environmental aspects of the building. Factual based measurement approach is adopted to reflect the status of the respective performance indicators. Building sustainability performance data were gathered by conducting a territory-wide benchmarking survey. The survey inputs were analysed via a statistical model, as such ranking for each sustainability performance indicator was generated, as a result the benchmarking tool to measure buildings sustainability performance in Hong Kong is formulated and made known to the public. Keywords: Buildings Benchmarking; Building Life Cycle; Sustainability; Sustainability Performance Indicators; Sustainable Building Index. 1. INTRODUCTION Over the past decade, various green building rating systems or certification schemes were promoted across the globe. For instance, BREEAM is the BRE Environmental Assessment Method owned and operated in the UK by BRE Global (BREEAM, Accessed 31 May 2013); CASBEE is the Comprehensive Assessment System for Building Environmental Efficiency owned and operated in Japan by the Japan Sustainable Building Consortium (CASBEE, Accessed 31 May 2013); GREEN STAR is the environmental rating system to evaluates the environmental design and construction of buildings and communities, owned and operated in Australia by the Australian Green Building Council (GREEN STAR, Accessed 31 May 2013); LEED is Leadership in Energy and Environmental Design, which is a green building rating system owned and operated in the USA by US Green Building Council (LEED, 2

238 Accessed 31 May 2013); and BEAM Plus is the environmental assessment scheme for new buildings and existing buildings, which is owned by BEAM Society Limited, recognised by the Hong Kong Green Building Council and operated in Hong Kong (HKGBC et al., Accessed 31 May 2013). This phenomenon shows that the environmental performance of buildings has becomes the an international core issue. However, the social and economic performance also plays an important role in measuring the sustainability performance of buildings (Clare Lowe et al., 2009). In addition, incidents related to ageing, maintenance, safety, security, quality and environmental issues of buildings in recent years has clearly signifyied the need of durable and sustainable buildings. In view of this, the Hong Kong Quality Assurance Agency (HKQAA) endeavors to develop a territory-wide benchmarking tool HKQAA Sustainable Building Index (HKQAA SBI). 2. BACKGROUND OF HKQAA SBI HKQAA SBI (The index) aims to encourage the users of buildings, such as building owners or property managers, to periodically evaluate buildings sustainability performance along withthroughout the building life cycle in terms of the triple bottom line principle, i.e. the environmental, social and economic aspects, such so that improvement opportunities can be identified for subsequent enhancement. The ultimate goal of the index is to drive for promote the culture towards sustainability sustainable development in Hongk Kong in the long run. The uniqueness of the index index is that to not alike the common international green building rating systems or certification schemes, it it focuseses on the building s evaluation ofin the operational phase of the buildingsevaluation with regard to the triple bottom line principle, whilst some in majority the international green building rating systems are mainly encompassed the building s design and construction phases evaluation merely on within the environmental aspect. The index is formulated to provides a flexible application tofor different users, and it is applicable to any type of buildings, namely, which includes domestic building, accommodation building, office building, industrial building and shopping centre. The index offers a composite index of current building sustainability performance indicators and it encompasses 20 performance indicators (P.I.) for evaluating the performance of existing buildings under 10 core issues with respect to under the social, economic and environmental arenas of the buildings. The indicators are easily understandableood by various building professionals. Each indicator is supplemented with a detailed or technical definition or explanation in order to minimise potential misinterpretation and the risk of ambiguity. for each indicator. Factual based measurement approach is adopted to reflect the status of the respective performance indicators. Building sustainability performance data were gathered through by conducting a territory-wide benchmarking survey in The survey inputs were analysed via a statistical model, as such ranking for each sustainability performance indicator was generated, as a result the benchmarking tool to measure buildings sustainability performance in Hong Kong is formulated and made known to the public. The index raises aims to raise the awareness to building sustainability awareness of both professional and the public;, as a clear messages regarding of building sustainability issues are is to be conveyed to thosethe professionals who may enthuses 3

239 in bringing improvement towardsultimately bring about improved sustainable development in Hong Kong., on the other hand Furthermore, the index is designed and formulated to disseminate the message to the general public. By subscribing toto the index, introduction of innovativeon and advancedappropriate technology are highly encouraged so as to improve the overall built environment throughout the building life cycle of the building. 3. OVERVIEW OF HKQAA SBI FRAMEWORK 3.1. FRAMEWORK DEVELOPMENT The framework of the index is made reference to the latest international standards and best practices related to of the sustainability in building construction together with several key ISO standards. According to ISO/DIS 26000, the the concept of sustainable development consists of three interdependent dimensions economic, social and environmental (International Standardization Organization, ). In addition, ISO/TS and ISO concur that the sustainability performance of buildings should be closely linked with the environmental, social and economic aspects in its life cycle (International Standardization Organization, 2008 and 2006). By reviewing the common international green building rating or certification schemes and UNEP SBCI research papers, suitable i Indicators of the respective Issues have beenwere identified. The index offers a composite evaluation method for measuring the current building sustainability performance of the buildings related in theto its social, economic and environmental aspects of a building. It focuses on measurable outcomes that can be linked to current statutory requirements, recommended practices and the Hong Kong building sustainability performance data gathered from desktop research or the territory-wide building sustainability performance benchmarking survey conducted by HKQAA PERFORMANCE INDICATORS The index encompasses 20 performance indicators (P.I.) for tracking and evaluating the performance of 10 core issues of the social, economic and environmental aspects of a chosen building. The performance indicators with regards to each core issues in different aspects are tabulated in table 1. Table 1: Performance Indicators of HKQAA SBI Aspects Issues Performance Indicators Environmental Climate Change Greenhouse gas (GHG) Emissionsemissions Ozone Destruction Release of ozone-depleting substances into the atmosphere Biodiversity Use of Resources Ecology in building Use of fresh water Use of biodegradable or organic materials Waste recycling Social Building Security and Safety Building strength and quality Fire prevention Safety of lifts and escalators Emergency planning Designing out crime Health and Comfort of Users User comfort Lighting comfort 4

240 Aspects Issues Performance Indicators User comfort Thermal comfort User comfort Noise control Indoor air quality Quality of fresh water Social Infrastructure Accessibility to transportation, public facilities and barrier free facilities Harmonized Neighbourhood Relationship Neighbours satisfaction Economic Asset Value Rateable value of building Building Maintenance Expenses on maintaining building s operational continuity 4. TERRITORY-WIDE BENCHMARKING SURVEY The territory-wide benchmarking survey (the Survey) was conducted by the HKQAA from July to November Information collected from the Survey provides a wealth of data on the sustainability performance in the environmental, social and economic aspects of the buildings in Hong Kong. The objective of the Survey is to identifyfind out the norms of the building s sustainability performance in Hong Kong, which form the measurement benchmarks of the Index METHODOLOGY COVERAGE OF THE SURVEY The Survey covers 5 building types, they are Domestic Building, Accommodation Building, Industrial Building, Office Building and Shopping Centre DATA COLLECTION AND CONVERSION Operational performance data were collected from the buildings that fall into the scope of the survey, which coverscovering the following issues: Waste recycling; Use of fresh water; Consumption of refrigerant with ozone-depleting substances; Use of environmentally-friendly materials; Criminal case reporting; Provision of emergency plans; Installation of ecological facilities; Greenhouse gas emissions; and Percentage change in rateable value of building. In addition, the basic information of the building, such as the saleable area of the building, age of building, building type and the location of the building, was collected for analysis. Data was collected by self-administered questionnaire. A set of questionnaire along with a covering letter was mailed, ed and faxed to the building owners, property managers, incorporated owners, owners committee, etc. of the sampled buildings. 5

241 Installation of ecological facilities Greenhouse gas (GHG) emission Consumption of refrigerant with ozonedepleting substances Findings Categories Sustainable Building 2013 Hong Kong Regional Conference The figure was reported on both the basis of per 10,000 square feet of saleable are of building and the basis of an accumulation of the data of the past 12 months, therefore the data of the buildings with different size can be analysed on the same basis SAMPLE SELECTION Buildings from the database of the Home Affairs Department of HKSAR and those managed by HKQAA s clients were invited to participate in this Survey. In total, 813 building undertakings that fell within the scope of the survey were successfully enumerated. Data reported by the respondents have been thoroughly checked to ensure that they are reliable for analysis. Checked items included completeness of entries, consistency among data items and creditability of reported data. Dubious cases were followed by telephone call or by field verification visit RESULT MAJOR FINDINGS OF THE SURVEY As reflected in the Survey, several major findings are discovered and listed in table 2. Table 2: Major Findings of the Survey Domestic and Accommodation Buildings Industrial Buildings, Offices and Shopping Centre Over 50% of the buildings reported 0kg consumption. For buildings using ozone depleting refrigerant, the average consumption is around 1kg. The range is from 0 to 16kg. The age of buildings that do not consume ozone depleting refrigerant is generally 5 years older than those buildings that consumed ozone depleting refrigerant. The average emissions are 18 metric tons. The range is from 0.7mT to over 300mT. The average emissions for buildings situated in Hong Kong Islands are around 4mT lower than those situated in Kowloon and New Territories. The GHG emissions of buildings aged above 30 years old are significantly lower than those buildings with less than or equal to 30 years old. Over 88% of buildings installed 1 to 3 types of ecological facilities (out of 10 suggested facilities). The range is from 0 type to 7 types. Garden, landscaping with Native Plants and Nursery Plants are commonly found. Over 80% of the buildings reported 0kg consumption. For buildings using ozone-depleting refrigerant, the range is from 2kg to over 1,000kg. No significant differences in age and saleable area between buildings that consumed or not consumed ozone depleting refrigerant. The average emissions are 178 metric tons. The range is from 0.36mT to over 3,000mT. No significant difference between Industrial Buildings and Offices and Shopping Centre on the average emissions. The GHG emissions of buildings aged above 30 years old are significantly higher than buildings with less than or equal to 30 years old. Over 90% of building installed 1 to 2 types of ecological facilities (out of 10 suggested facilities). The range is from 0 type to 3 types. Landscaping with Native Plants and Nursery Plants are commonly found. 6

242 Waste recycling Use of fresh water Use of environment ally friendly materials Provision of emergency plan Findings Categories Sustainable Building 2013 Hong Kong Regional Conference Domestic and Accommodation Buildings Industrial Buildings, Offices and Shopping Centre The performance of public buildings and private buildings are similar. The performance of shopping centre, office and industrial buildings are similar. Over 55% of building installed 7 to 8 types Over 50% of building installed 6 to 8 of emergency plans (out of 11 suggested types of emergency plans (out of 11 plans). suggested plans). Buildings aged less than or equal to 30 Buildings aged less than or equal to 30 years old are generally better than years old are generally better than buildings aged above 30 years old. buildings aged above 30 years old. Buildings in average used 3.65 types of Buildings in average used 2.48 types of biodegradable materials (out of 8 biodegradable materials (out of 8 suggested materials). suggested materials). Recycled materials, locally produced Recycled materials and locally produced materials and biodegradable materials are materials are commonly used. commonly used. The average consumption is 215 m 3. The average consumption is 1,201 m 3. The range is from 0m 3 to over 7,000m 3. The range is from 0m 3 to over 4,400m 3. The consumption for buildings in Kowloon The consumption for shopping centre and New Territories is generally higher was significantly higher than that of office than that of buildings in Hong Kong Island. and industrial building. The average recycled amount is 1,304kg. The average recycled amount is 2,573 kg. The range is from 0kg to over 12,000kg. The range is from 0kg to over 150,000kg SCORING APPROACH By analysing the survey data with our statistical model, a representative 3-level ranking scorecard is developed for each performance indicator. The performance data collected were ranked and divided into three equal intervals. The lower and upper boundaries of the middle intervals will be set as the mark for scoring. According to different questions, the group ranked ahead will score the highest 3, the other two groups will score 2 and 1 in sequence. 5. BENCHMARKING PROCESS The benchmarking process consists of 4 steps. Step 1: Submission of subscription form Buildings representatives wishing deciding to subscribe to the Index should complete and submit the HKQAA SBI subscription form to HKQAA, indicating the subscription category opted for. The subscription categories are Verified Report Disclosure and Self-Declared Report Disclosure. Step 2: Filling in the building sustainability performance report Buildings representatives should fill in their sustainability performance in the HKQAA SBI Metrics Handbook and Report Template. Note: Buildings subscribing to the Verified Report Disclosure category have to engaged thea listed SBI verifierd to verify the integrity of the reported information before submitting the report to HKQAA. 7

243 Step 3: Compiling of the HKQAA SBI score HKQAA will calculate the Index score of the subscribing buildings by comparing the buildings reported performance in accordance withto the three levels of performance targets., with a maximumhighest score of 3 to bebeing awarded to buildings which conform to the level 3 criteria, and so on. Scores are then aggregated and averaged to arrive at the final HKQAA SBI score. Step 4: Disclosure of reported performance The reported performance information of the Subscribing buildings reported performance information will be publisheddisplayed on the HKQAA SBI website. Buildings will be entitled to use the HKQAA SBI Mark, either HKQAA SBI Self- Declared Mark or HKQAA SBI Verified Mark in their printed materials and websites. This Mark will also be showndisplayed on the HKQAA SBI website next to the building s name. 6. SUMMARY HKQAA SBI is a building sustainability performance disclosure and benchmarking scheme developed based on the latest international standards and best practices of the sustainability in building construction together with several key ISO standards, with the following benefits: A simple and inexpensive tool for building stakeholders to benchmark, discloseure and understand the sustainability performance of their buildings; Identifies areas for continual improvement, enhances the building s performance and sustains valuationappreciation potential; Showcases Demonstrates the building s quality and value by reporting of sustainability performance; Designed with a balance of social, economic and environmental considerations; Facilitates buildings to measure and benchmark their sustainability performance against the norm performance of the buildings in Hong Kong as a whole. 7. ACKNOWLEDGEMENTS With many thanks for the generous contribution of: Ir Prof. Peter M.K. Mok, Chairman at Hong Kong Quality Assurance Agency; Mr. PC Chan, Chief Operating Officer at Hong Kong Quality Assurance Agency; Mr. Coleman Tse, General Manager of Construction Branch at Hong Kong Quality Assurance Agency. 8. REFERENCE BEAM, 2012 BEAM Society Limited. About BEAM [online]. Available from: [Accessed 31 May 2013]. BREEAM, BRE Global About BREEAM [online]. Available from: [Accessed 31 May 2013]. CASBEE, Japan Green Build Council (JaGBC) / Japan Sustainable Building Consortium (JSBC). Overview [online]. Available from: [Accessed 31 May 2013]. 8

244 GREEN STAR, Green Building Council of Australia Green Star overview [online]. Available from: [Accessed 31 May 2013]. HKGBC, 2013 Hong Kong Green Building Council Limited. BEAM Plus [online]. Available from: [Accessed 31 May 2013]. International Standardization Organization, ISO Sustainability in Building Construction General Principles. 1 st Place of Publication, Geneva. International Standardization Organization, ISO/DIS Guidance on Social Responsibility. 1 st Place of Publication, Geneva. LEED, 2013 U.S. Green Building Council. LEED [online]. Available from: [Accessed 31 May 2013]. 9

245 ZERO CARBON BUILDINGS: A POLICY REVIEW Wei Pan 1 and Yan Ning Department of Civil Engineering, The University of Hong Kong, Hong Kong 1 Corresponding Author wpan@hku.hk, Tel: (852)

246 ZERO CARBON BUILDINGS: A POLICY REVIEW ABSTRACT Zero carbon building (ZCB) has been regarded in many countries and regions as an important approach to reducing the GHG emissions and energy consumption associated with buildings. This paper aims to review the policies relevant to ZCB in the world and Hong Kong in particular. It is found that despite emerging ZCB policies in a number of countries, most of them are grounded on the specialisation of research into ZCB, i.e. the carbon emissions associated with the energy use of a building are zero or negative over a period of time, which oversimplifies the multiple functions of as well as the multiple challenges facing buildings. There also exists a lack of knowledge of systems ZCB policy models, and the sharing of this knowledge is constrained. In Hong Kong, although the first ZCB has been built with government support, there exists little reported research on how ZCB practice can move from prototypes to mainstream industry practices. Nevertheless, the existing building carbon and energy regulations, codes and policies in Hong Kong, within its overall carbon, energy and climate change policy context, go beyond the building sector and interact with energy supply and the market of end-users and occupants. It is suggested that policy attention should be paid to how, rather than if, a ZCB policy could help transit the society and built environment of Hong Kong towards sustainability and low carbon. The ZCB policy should then be grounded on holistic theory to guide ZCB, in the form of both product and process, to address environmental, social and economic concerns within the physical, climatic, political boundaries of Hong Kong. Keywords: Zero carbon building; Energy policy; Energy efficiency; Renewable energy; Review. 1. INTRODUCTION Zero carbon building (ZCB) has been regarded in many countries and regions as an important approach to reducing the GHG emissions and energy consumption associated with buildings (Wilford and Ramos 2009; Pan and Garmston 2012). However, very few countries and regions have set their ZCB policies, most regarding it as part of their climate change policy or building energy codes and regulations. Hong Kong has been working closely with the international community to cope with the impact of climate change and mitigate GHG emissions. Notably, the Hong Kong Special Administrative Region (HKSAR) government devised Hong Kong s Climate Change Strategy and Action Agenda and proposed setting a target to reduce the carbon intensity level in Hong Kong by 50-60% by 2020 as compared with 2005 (Environment Bureau 2010). In the building sector in Hong Kong, there have been a series of building energy codes and regulations from the first Building (Energy Efficiency) Regulation Cap.123 implemented from July 1995 to the Building Energy Efficiency Ordinance came into full operation from September However, underlying all these regulations is an incremental policy approach, with a lack of a strategic outlook for achieving ZCBs. The first ZCB in Hong Kong was completed in 2012 but remains as a prototype to showcase state-of-the-art eco-building design and technologies to the construction industry internationally and locally and to raise community awareness of sustainable living in Hong Kong (Construction Industry Council CIC 2012: 2), far from mainstream practice. It remains underexplored but the most challenging if and how a ZCB policy should be established to help achieve a low carbon economy in Hong Kong. Therefore, this paper aims to examine ZCB policies in the world and building carbon and energy policies in Hong Kong, and to develop recommendations for establishing a possible ZCB policy in Hong Kong. 2

247 2. ZCB POLICIES IN THE WORLD Some countries and regions have set their ZCB policies, explicitly or implicitly as part of their climate change policy or building energy codes and regulations (see Table 1). Initiatives Communities and Local Government (CLG, 2008) European Directive 2010/31/EU (recast) (European Commission, 2010) Energy Independence and Security Act 2007 (EISA, 2007) Presidential Executive Order (EO)13514 (Federal office, 2009) Table 1: ZCB INITIATIVES AND TARGETS Targets 2010 to a 25 per cent improvement in the energy/carbon performance set in Building Regulations; then second, in 2013, to a 44 per cent improvement; then, finally in 2016, to zero carbon. As of 31December 2020, all new buildings are nearly zero-energy buildings After 31December 2018, new buildings occupied and owned by public authorities are nearly zero-energy buildings As of 2025, all new commercial buildings must be zero net energy As of 2050, all US commercial buildings must be zero net energy including retrofits of pre-2025 buildings As of 2020, all planning for new Federal buildings requires design specifications that achieve zero net-energy use As of 2015, large government buildings have to start showing progress As of 2015, at least 15%of any Federal agency s existing buildings and building leases above 500m 2 must conform to zero net energy and ongoing improvements are required The UK is the first country to set a timetable for delivering ZCBs, i.e. to achieve zero carbon for domestic buildings from 2016 and for non-domestic buildings from 2019 (CLG 2008). However, the definition and policy of ZCB, since its announcement in 2006, have encountered serious debate. A key point of the debate is the scope of the energy with which carbon emissions are associated, i.e. from the original proposed genuine or complete zero carbon (including both regulated, i.e. for space heating, cooling, ventilation, lighting and hot water; and unregulated energy, i.e. for cooking, washing and electronic entertainment appliances, DCLG 2006:7) to regulated energy only (HM Treasury 2011:117). Another point of debate is the three-tier hierarchy of measures to achieving zero carbon, i.e. energy efficiency, carbon compliance, and allowable solutions (CLG, 2008b), with the allowable solutions being criticised for its fundamental weakness (McLeod et al. 2012:29). European Directive 2002/91/EC on the energy performance of buildings (EPBD) and the EPBD recast (Directive 2010/31/EC) are the main two legislative instruments for improving building energy efficiency in European Union (EU). EPBD mandates that by 2006 all EU Member States bring into force national laws, regulations and administrative provisions for setting minimum requirements on the energy performance of new and existing buildings above 1000m 2 that are subject to major renovations, and for energy performance certification (EPC) of buildings (Dascalaki et al. 2012). The key points of the EPBD recast include (Dascalaki et al. 2012): All new buildings must be nearly zero energy buildings after 31 December 2020, while new buildings occupied/owned by public authorities must be nearly zero energy buildings after 31 December 2018; All EU Member States implement a common methodology for calculating the integrated energy performance of buildings using common benchmarks for calculating cost-optimal levels, minimizing the building s life cycle cost; All existing buildings that undergo major refurbishment (25% of building surface or value) should meet minimum energy performance standards and not only for those above 1000m 2 foreseen in EPBD, while national policies and specific measures should stimulate the transformation of refurbished buildings into nearly zero energy buildings; 3

248 EPC is issued for buildings or building units which are rented out to a new tenant and buildings where a total useful floor area over 500m 2 is occupied by a public authority and frequently visited by the public; All EU Member States introduce minimum energy use requirements for all HVAC technical building systems. By Executive Order 13514, US President Barack Obama mandated that by 2015, 15% of existing Federal buildings conform to new energy efficiency standards and 100% of all new Federal buildings be Zero-Net-Energy by 2030 in US (Federal office, 2009). For commercial buildings in US, another zero energy agenda was set in Energy Independence and Security Act 2007: as of 2025, all new commercial buildings must be zero net energy; as of 2050, all US commercial buildings must be zero net energy including retrofits of pre-2025 buildings (EISA, 2007). A net-zero energy building (NZEB) here refers to a building that produces as much energy as it uses when measured at the site. On an annual basis, it produces or consumes as much energy from renewable sources as it uses while maintaining an acceptable level of service and functionality (ASHARE, 2008). In Australia, no policies pertaining to ZCB were explicitly formulated, although the Australian Sustainable Built Environment Council (ASBEC) has proposed the definition of ZCB and roadmaps to ZCBs (see ASBEC, 2012; Riedy et al., 2012). The policy most relevant to ZCB to date is the Nationwide House Energy Rating Scheme (NatHERS), which uses computer simulations to assess the potential thermal comfort of Australian homes on a scale of zero to 10 stars. The more stars, the less likely the occupants need cooling or heating to stay comfortable. Occupants of a 10 star home are unlikely to need any artificial cooling or heating. Before the introduction of national energy efficiency regulations for houses in 2003, less than one per cent of Australian houses achieved NatHERS 5 stars. Many well designed houses are now being built with ratings over 6 stars (NatHERS, 2008). Despite an emerging of ZCB policies in a number of countries, most of them are grounded on the specialisation of research into ZCB, i.e. the carbon emissions associated with the energy use of a building are zero or negative over a period of time (e.g. Torcellini et al. 2006; Marszal et al. 2011; Sartori et al. 2012), which oversimplifies the multiple functions of as well as the multiple challenges facing buildings; hence problematic. Also, the existing ZCB policies seem to adopt various principles, with no general consensus on how the boundaries of the carbon emissions, the energy use, the building and the period of time, when interpreting ZCB, can be defined. There is a lack of knowledge of systems ZCB policy models, and the sharing of this knowledge is constrained. 3. THE CASE FOR A POSSIBLE ZCB POLICY IN HONG KONG 3.1GHG EMISSIONS AND ENERGY CONSUMPTION IN HONG KONG Hong Kong is a service-based economy with no energy-intensive industries. By type of energy end-use, electricity accounts for more than half (53.7% in 2010) of Hong Kong energy end-use, followed by oil and coal products (29.3%), and then town gas and LPG (16.4%), with a very small share of renewable energy (0.6%) (EMSD 2012). By type of sector, commercial accounts for 42% (in 2010) of HK energy end-use, followed by transport (32%), residential (20%) and then industrial (6%) (EMSD 2012). Electricity generation is the major source (accounting for typically over 67%; Figure 1) of GHG emissions in Hong Kong (EPD 2012), followed by transport (around 17%). 4

249 Town gas production accounts for only about 1% of GHG emissions caused by energy production. The use of fuel for combustion in commercial, industrial and domestic premises accounts for a very small share (less than 7%) of the total GHG emissions (EPD 2012). Therefore, the fundamental strategy for reducing GHG emissions in Hong Kong is to reduce GHG emissions associated with electricity generation. Figure 1 GHG EMISSIONS IN HONG KONG BY SECTOR Figure 2 ELECRICITY CONSUMPTIONS IN HONG KONG BY SECTOR Among various end uses of electricity, all buildings account for about 90% (Figure 2) (EMSD 2012). Therefore, the further fundamental strategy for bringing down GHG emissions in Hong Kong is to reduce and/or decarbonise electricity consumption for building operations. 3.2 OVERALL CARBON, ENERGY AND CLIMATE CHANGE POLICIES IN HONG KONG During the past two decades or so Hong Kong has undertaken a series of initiatives to reducing GHG emissions in addressing climate change. The HKSRA, as part of China, is a Party to the United Nations Framework Convention on Climate Change (UNFCCC) (adopted in New York on 9 May 1992) and its Kyoto Protocol (1998). The UNFCCC is an international treaty committing countries to take steps to reduce the threat of global climate change. Countries that have signed and ratified the UNFCCC agreed to work towards achieving an ultimate objective of stabilizing "greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system". The Kyoto Protocol further commits industrialized countries to reduce their combined greenhouse gas emissions by at least 5% compared to 1990 levels over the period Along with 20 other Asia-Pacific Economic Co-operation (APEC) economies, Hong Kong has subscribed to the Sydney Declaration on Climate Change in September 2007, working towards achieving an aspirational goal to reduce energy intensity in the Asia-Pacific region by at least 25% by 2030 from the 2005 level (c.f. EPD and EMSD 2010: 4). Hong Kong joined the C40 Cities Climate Leadership Group (C40; in October Formed in 2005, C40 aims to promote collaboration amongst cities in the world to reduce greenhouse gas emissions and enhance energy efficiency. London, Tokyo, New York, Sydney, Beijing and Shanghai are among the participating cities. The Government will work closely with the participating cities to combat climate change. The Hong Kong SAR government devised Hong Kong s Climate Change Strategy and Action Agenda and proposed setting a target to reduce the carbon intensity 5

250 level in Hong Kong by 50-60% by 2020 as compared with 2005 (Chief Executive 2010). In the Policy Address , the Chief Executive (2011:37-38) commented that We also suggested a number of emission reduction measures and are now seeking input from the community to improve energy efficiency and enhance the management of electricity demand, and On the wider use of clean energy, we are consolidating views collected during public consultation. In deciding the power generation fuel mix in the future, we will take into account the impact of the Fukushima incident earlier this year on nuclear energy development, and balance such factors as safety, reliability, environmental protection and affordability. Also, the HKSRA Government has been promoting the use of cleaner fuel and renewable energy for over a decade in order to reduce the production of GHG from power generation. The construction of new coal-fired generating units has been banned since 1997 in favour of natural gas, which emits around 50% less GHG for the same amount of electricity produced (Environment Bureau, 2010). The Government has also signed a Memorandum of Understanding with National Energy Administration in August 2008 to ensure a long-term and stable supply of nuclear electricity and natural gas (for a further term of 20 years). For renewable energy, the HKSAR Government has also proposed to increase the share of renewable energy to about 3-4% of the fuel mix by 2020 in the Hong Kong s Climate Change Strategy and Action Agenda consultation document (Environment Bureau, 2010). The current Scheme of Control Agreements (SCAs), signed between the Government and the two power companies, includes provisions to encourage the use of renewable energy sources. Under the SCAs, the companies will enjoy a higher rate of return on investment in renewable energy facilities, and will be offered bonuses in the level of permitted return depending on the extent to which they use renewable energy and the environmental performance of their electricity generation (GovHK, 2012). 3.3 BUILDING CARBON AND ENERGY REGULATIONS, CODES AND POLICY IN HONG KONG Building energy codes and regulations in Hong Kong have evolved during the past nearly two decades since their introduction, towards more stringent requirements on energy efficiency (Table 2). Table 2 BUILDING ENERGY CODES (BEC) IN HONG KONG Time BEC in Hong Kong Status Scope Jul The first Building (Energy Efficiency) Regulation Cap.123 was implemented 1998 BEC (lighting and air-conditioning) 1999 BEC (Electrical) 2000 BEC (lift and escalator) 2004 Performance based Sep The Building Energy Efficiency Ordinance came into full operation Mandatory by BD Voluntary by EMSD Voluntary by EMSD Voluntary by EMSD Voluntary by EMSD Mandatory Building envelope (OTTV); commercial buildings and hotels All buildings except domestic, industrial and medical ones All buildings except for special industrial process All buildings except for special industrial process All buildings except for special industrial process 6

251 In 1995 the first Building (Energy Efficiency) Regulation was implemented in Hong Kong. In October 1998, EMSD has launched the voluntary Hong Kong Energy Efficiency Registration Scheme for Buildings (HKEERSB) to promote the application of the Building Energy Codes. The BECs cover lighting, air conditioning, electrical, and lift and escalator installations, which stipulate the minimum energy performance standards (MEPS) of these installations. Up to Sep 2012, 3257 registration certificates were issued to 1462 building venues involving 3412 installations (EMSD 2012). The abovementioned four BECs, launched from 1998 to 2000, are of prescriptive nature and are often called the prescriptive BECs (2005 and 2007 Editions). EMSD launched in April 2003 the fifth code - Performance-based Building Energy Code (BEC(PB)) (2005 and 2007 Editions). The BEC(PB) focuses on a building's total energy consumption as compared to the energy budget of a hypothetical building (a building meeting all the prescriptive code requirements), and the energy saving over the energy budget can be used as a trade-off for some of the requirements in the prescriptive codes. The BEC(PB) serves to provide compliance flexibility to energy efficient design and to encourage innovative design, such as the capture of daylight benefit, adoption of heat recovery and use of renewable energy. The Buildings Energy Efficiency Ordinance (Cap. 610) was enacted in 2010 and has come into full operation from 21 September 2012 onward, to stipulate the minimum energy performance standards (i.e. to comply with the design standards of the Building Energy Code (BEC), currently the BEC 2012 Edition) of four major building services installations, namely, lighting, air conditioning, electrical, and lift and escalator installations (EMSD 2012). Apart from the mandatory measure, the Government also rolled out the Buildings Energy Efficiency Funding Schemes on April to subsidise building owners to carry out energy-cum-carbon audits as well as energy improvement projects, which ended on April as scheduled. Building carbon and energy regulations, codes and policy in Hong Kong also promote energy efficiency and conservation of building-related products and systems. The HKSRA Government had implemented the initial phase of Mandatory Energy Efficiency Labelling Scheme in 2008 through the legislation of Energy Efficiency (Labelling of Products) Ordinance (GovHK, 2013). The initial phase of the scheme required room air-conditioners, refrigerating appliances and compact fluorescent lamps to carry energy labels before they were supplied to the local market. To further facilitate consumers in choosing energy-efficient products, the Government extended the coverage of the scheme to washing machines and dehumidifiers in the second phase. The second phase was fully implemented on 19 September Other than the energy efficiency control in products, there is a movement towards regional development. The Government will implement a district cooling system (DCS) at the Kai Tak Development to supply chilled water to buildings for energy-efficient airconditioning purpose. The maximum annual saving in electricity consumption will be up to 85 million kwh per annum (GovHK, 2012). 4. CONCLUSIONS Although ZCB policies have emerged in a number of countries, most of them are grounded on the specialisation of research into ZCB, i.e. the carbon emissions associated with the energy use of a building are zero or negative over a period of time, which oversimplifies the multiple functions of as well as the multiple challenges facing buildings; hence problematic. Also, the existing ZCB policies seem to adopt various principles, with no general consensus on how the boundaries of the carbon emissions, 7

252 the energy use, the building and the period of time when interpreting ZCB can be defined. There is a lack of knowledge of systems ZCB policy models, and the sharing of this knowledge is constrained. In Hong Kong, although the HKSAR government has committed to addressing climate change, the policies on reducing GHG emissions of buildings have been incremental, with no ZCB policy in place to the time of writing this paper. The first ZCB has been built in Hong Kong with government support, which may be a signal of efforts exploring the future of building carbon and energy policy towards zero carbon. However, there exists little reported research on how ZCB practice can move from prototypes to mainstream industry practices. Nevertheless, the existing building carbon and energy regulations, codes and policies in Hong Kong, within its overall carbon, energy and climate change policy context, go beyond the building sector and interact with energy supply and the market of end-users and occupants. It is suggested that policy attention should be paid to how, rather than if, a ZCB policy could help transit the society and built environment of Hong Kong towards sustainability and low carbon. The ZCB policy should then be grounded on holistic theory to guide ZCB, in the form of both product and process, to address environmental and social and economic concerns within the physical, climatic, political boundaries of Hong Kong. 5. REFERENCES ASHARE ASHRAE Vision 2020, providing tools by 2020 that enable the building community to produce market-viable NZEBs by 2030 [on line]. Available from [accessed on 30/06/2013]. ASBEC Net zero emission homes: an industry roadmap [on line]. Available from [accessed on 30/06/2013]. CIC ZCB Fact Sheet, Construction Industry Council (CIC), Hong Kong. Chief Executive Sharing Prosperity for a Caring Society, Policy Address, Government of the HKSRA, Government Printer, Hong Kong. Dascalaki, E.G., Balaras, C.A., Gaglia, A.G., Droutsa, K.G. and Kontoyiannidis, S. (2012) Energy performance of buildings-epbd in Greece. Energy Policy, 45, DCLG Definition of zero carbon homes and non-domestic buildings: consultation, London: UK. EMSD Code of Practice for Energy Efficiency of Building Services Installations [on line], Available from [accessed on 30/06/2013]. EMSD The Buildings Energy Efficiency Ordinance (Cap. 610), EMSD: HK. Environment Bureau, Hong Kong s climate change strategy and action agenda consultation document. Environment Bureau, HKSAR Government. Federal Office, Federal leadership in environmental, energy and economic performance - EXECUTIVE ORDER [on line]. Available from [accessed on 30/06/2013]. GovHK Climate Change [on line]. Available from [accessed on 30/06/2013]. GovHK Energy Efficiency & Conservation [on line]. Available from [ accessed on 30/06/2013]. HM Treasury The Plan for Growth, HM Treasury, London. Marszal, A.J., Heiselberg, P, Bourrelle J.S., et al Zero energy building a review of definitions and calculation methodologies. Energy and Buildings, 43(4): McLeod, R. S., Hopfe, C. J. and Rezgui, Y., An investigation into recent proposals for a revised definition of zero carbon homes in the UK. Energy Policy, 46, Pan, W. and Garmston, H., Compliance with building energy regulations for new-build dwellings. Energy, 48(1), Riedy, C., Lederwasch, A. and Ison, N., Defining zero emission buildings review and recommendations: final report. Sartori, I., Napolitano, A. and Voss, K., Net zero energy buildings: A consistent definition framework. Energy and Buildings, 48, Torcellini, P., Pless, S., Deru, M., and Crawley, D., Zero energy buildings: A critical look at the definition. Preprint. ACEEE Summer Study Pacific Grove. California, USA, August, Wilford, C. and Ramos, M., Zero Carbon Compendium: Who s Doing What in Housing Worldwide, NHBC Foundation, Amersham. 8

253 Sustainable Buildings and use of Advanced Technology in Current Practice in PRC Malcolm Laverick CEng, FCIBSE, FHKIE, MASHRAE AECOM Limited, China 36-38/F Wheelock Square 1717 West Nanjing Road Shanghai China

254 Sustainable Buildings and use of Advanced Technology in Current Practice in PRC The purpose of this paper is to share our recent experiences in creating new building designs and how we see China, which is developing at great speed is addressing the sustainable design approach. This paper presents case studies that demonstrate the trend in recent years in China and how technology and sustainable approach have been applied to transform the industry from high consumption design to low energy and low carbon, environmentally friendly solutions. The paper draws on the personal experience that AECOM Building engineering teams who have been engaged in a number of high-end development projects in China realize such approach and innovative technology applications. These real project examples illustrate the importance of integrated solutions across not only engineering but planning, architecture, interior and construction management aspects and also take the life time operation and maintenance aspects into account in the early stages of the project. This has resulted in providing a clear direction for the projects to reach the sustainability targets. The use of appropriate technology has played a major part in the design including micro climate study, building thermal analysis, day-lighting performance, energy and carbon consumption modeling and BIM. It will also demonstrate the varying external environments in China in which these buildings are located and how there is a need to consider such environments in finding appropriate sustainable solutions. We have concluded that whilst there is an underlying current of desire to achieve such objectives of a sustainable design, and in many cases this is achieved, there are more opportunities to expand such objectives into the wider market place. To achieve this objective professional designers will need to continue to expand their knowledge base, gain personal in country understanding of the environment and the development process so that such skills can be brought to bear on the buildings of the future. Keywords: innovative technology; integrated solutions; local knowledge; sustainable design. 1. INTRODUCTION The application of sustainable design and smarter construction is a growing trend in China as China seeks to expand its building stock to cater for both international and local development with reduced liability on energy and on-going operational costs. This changing pattern in design and procurement, has expanded significantly in the last 2 years and the first buildings are now well into construction or coming on line. As a provider of design services, covering full multi-discipline capability working across the whole of China we have played a part in this changing approach and this paper provides examples of current projects where such practice is being adopted. Design solutions that were considered not feasible in China are now being adopted and whilst there still remains large sectors of the built environment that follows traditional solutions the more ambitious clients that recognise the benefits of investing in the building stock to improve performance is growing. From the construction perspective contractors with a desire to improve and follow the new trends are actively developing their business around such models and growing their teams to react to the new quality and efficient design and construction business and will learn quickly from the consultants who are currently developing highly efficient strategies and quality buildings. They have recognised the need to enhance their skill base and take a more proactive approach to win, invest and construct this new era of buildings. 2

255 2. INTEGRATED DESIGN SOLUTIONS The ability to communicate remains a key component to achieving the success of these new designs with strong sustainable features. We see a growing interest in single source supply with internal management coordinating the detail and providing a single point of contact. Where the project still requires external offshore consultant interface is primarily in terms of the concept architecture where experienced knowledge in the building type mixed with a leading flair for design will require often an overseas architect or key designer in the early stages of design. China clients are always having the desire to have the best and most individual designs that separate them from others however the overseas designer requires support in terms of this local knowledge and code interpretation to ensure the design is progressed through a route that will not only be distinctive and innovative but also approved through the China codes and certification. This is particularly relevant in terms of life safety systems where we are often seeking to balance local code with international insurance requirements and sustainability solutions which may be commonplace outside China but are viewed with caution within China. Also the procurement of certified products and clients wish to retain the production of such materials in China. Bringing these variables together in China is demanding as we seek to create the sustainable design solutions. 3. CHINA CODE AND DRAWING STANDARDS The provision of China code that is not only National but also has local supplements which may take precedence together with the need to interpret codes and also deal with the process of Local Design Institute approval generates within itself a complex process. Add to this the desire in creating innovative sustainable solutions that may not have been tried and tested in China and one can see the complications that may ensue. The application of standard designs that are tried and tested remove risk however are less likely to recognize the latest technology and demanding standards required by Clients and the design team when creating the new sustainable designs. 4. BUILDING INFORMATION MODELING. As part of the drive to generate efficient sustainable construction the application of Building Information Modeling (BIM) is a growing initiative in China that is now being used as a real design tool to enhance the quality of the drawings prepared and ensure better coordinated and efficient solutions. It can now be seen that the application of BIM has driven smarter and more compact solutions, brought a surety of constructability to designs, reduced cost, improved maintainability however more needs to be done. The procurement of such 3D modeling requires to be carefully considered, it requires to be balanced against how he team is assembled. It cannot be seen as a bolt on service and needs to be integrated from the beginning as a design tool. This currently is not always understood in China and the true values more carefully explained and understood. The transfer of the model into the construction team is now a standard process with some contractors, to assist in the production of installation drawings, however the skill base requires to be upheld and the project knowledge base can be lost destroying the real values of this service. China is leading an initiative to develop BIM customized for the local market supported by independent consultants as well as the Local Design Institutes. 3

256 5. PROJECT EXPERIENCES. The following projects are live examples where the above issues have all been addressed as we seek to improve the performance of the building stock, produce energy efficient solutions and reduce carbon footprint. 5.1 PROJECT EXAMPLE 01 - RESEARCH AND DEVELOPMENT CAMPUS This project is located in Shanghai. The initial development encompassed two office buildings and two laboratory buildings in phase 1 and two office buildings and a cafeteria building in phase 1A. A combined basement accommodates a variety of facilities including an animal center, an energy center, car parks, plant rooms and other ancillary support provisions including a bomb shelter provision. A future phase 2 is planned. This is a multidisciplinary project that includes structural, MEP, landscape engineering, façade review, architectural lighting and BIM. A number of green technical solutions were incorporated such as Variable Air Volume (VAV), chilled ceilings, chilled beams, displacement ventilation / below floor air conditioning, fresh air and exhaust air volume controlled by the concentration of Carbon Dioxide (CO 2 ) in the occupied space, rainwater treatment and recycling system, solar water heating system. MEP coordination and 3D BIM modeling was carried out in key areas in order to demonstrate the design s maintainability and accessibility and then was fully modeled in 5No. buildings. Design deliverables were required to meet high international standards including bilingual (Chinese and English) documentation and be fully code compliant. The buildings are of 6 storey height and fall into the category of high rise and have a floor to floor height of generally 5 metres with internal ceilings at 3.2 to 3.5 metres. Floor voids vary from 200mm to 700mm depending on the application of use and environmental design solution. The initial requirement for the design was to address the building envelope. It was understood that if low energy consumption was to be achieved a high quality high performing envelope was essential both in terms of U value thermal transmittance and air leakage. Shanghai has a very wide band of external environmental conditions with periods of very low humidity and equally very high humidity so to apply some of these radiant cooling installations required control of fresh air and the operating temperature of the ceilings and chilled beams. Natural smoke ventilation and stair pressurization where desirable strategies and simplified the design form a safety perspective. A column free environment with a full height triple glazed faced required the application of CFD modeling to ensure the application of internal blinds was fully integrated with the perimeter air return system, glare and daylight calculations and the application of lighting control to create an environmentally acceptable working space adjacent the perimeter wall. To comply with environmental discharge requirements and dispersion of contaminated kitchen air exhaust plus fume cupboard exhaust site wide CFD site modeling was adopted to reduce any opportunity to a minimum for re-entrainment of this contaminated air. Some buildings focused heavily on building orientation and focused on solutions that used heavy weight structure to mitigate thermal transfer whilst others adopted a transparent solution for visual effect, external shading with perimeter balconies was adopted on one building and a move away from a typical curtain wall solution to a window wall application on another however the environment systems had to retain on a building by building basis the high performance requirements. Such variety and yet demanding visual and performing characteristics to be achieved has stretched the technology commitment and innovation. 4

257 Building envelope U-value and shading coefficient U-value w/m 2.k Shading Coefficient Eternal Wall(Including opaque curtain wall) 0.55 Roof 0.70 Floor 1.5 Partition 1.5 Window Sample Energy Performance Conditioned Area M 2 Watts / m 2 Watts / m 2 Cooling Load kw Cooling Index Heating Load kw Heating Index 4, PROJECT EXAMPLE 02 DEMONSTRATION BUILDING TIANJIN This 10-story commercial building in Tianjin incorporates the multiple functions of office, retail, exhibition and restaurant, with the development objective of being a demonstrative green building in the Tianjin Economic- Technological Development Area (TEDA). Four green building credentials were targeted: China Green Building (3- star grade), USA LEED (Gold grade), European BREEAM (Very Good level) and Japanese CASBEE (Grade S). We were commissioned as the structural, MEP and China Green Building, LEED and BREEAM certification consultants for this building to explore feasible state of the art green techniques which meet the most stringent criteria amid the four green building standards. AECOM s team worked closely with the client and the project team undertaking research over a period of 9 months to tackle technical aspects, explore options, and complete schematic design and extended preliminary design. Optimal green techniques adopted in this project include: - Passive design for all-year natural ventilation; - Double glazed (low-e) ventilated facade on the southern elevation and doublepane low-e facade on the northern elevation to achieve optimal building envelope performance; - High efficiency and low carbon emission MEP system and equipment utilizing under floor air distribution. - Other conservation measures include ground source heat pumps and SCBH15 high performance transformers; - Recycled grey water use for landscape irrigation, car washing and toilet flushing water - Water conservation sanitary fittings - Vertical and horizontal daylight tubes to basement and exhibition floors to reduce artificial lighting. - High efficiency lighting adopted for typical floors with auto occupancy and light level sensors. - Renewable energy sources including PV panels on the roof and PV vertical wall on the southern elevation, energy regeneration lifts, and solar hot water system; - Recyclable steelwork for structural perimeter columns, recycled aggregate concrete (RAC) for basement floors; - Other recyclable non-structural and architectural materials were widely used from local sources. The design achieved KWh/m 2 /y energy saving and Kg/m 2 /y carbon reduction in comparison with the benchmark specified in the national Public Building Energy Saving standard, i.e % energy and carbon reduction, respectively. The design of this project has successfully achieved the targeted grades of green building credentials. 5

258 Building Type Energy Consumption in KwHrs / square metre / year CO 2 Discharge in Kg CO 2 per sq metre 1980 Reference Building Building Based on GB Energy Saving Code LEED based Building Demonstration Building Performance Savings % Energy Saving % Carbon Saving CO2 Discharge Reduction Fresh Air Volume Control by Request Original Design Ground Source Heat Pump Dehumidify by Br-Li + heat Recovery PV Panels Horizontal Daylight Tubes Lift Energy Re-generation Solar Hot Water Underfloor Air Conditioning IPM Motor Vertiocal Daylight Tube Green Roof Wind Power Double Façade PROJECT EXAMPLE 03 A LOW CARBON ECO DEVELOPMENT This project is located in Ningbo and was developed to establish the area as a Low carbon eco-development. This coastal tourism and holiday resort, covering eight square kilometers, is located in an urban planning area, eight kilometers away from Xiangshan, Ningbo City, Zhejiang Province. This project required research to be carried out on how this low carbon eco-development could be established and prepare a strategy for environmental protection and enhancement of building energy efficiency. After site investigations, interviews with local experts and more than 200 surveys, Key Performance Indicators (KPI) were studied and guidelines were given to local district developers. These covered health and well-being, water efficiency, energy saving and low carbon, ecology and environment, materials and resources, as well as innovation in design. Specific building types were identified including low rise and high rise residential, commercial retail, commercial office and hotels and guidelines were established for each type. Specific directions that the Developer will be required to follow under the development of this area include: 6

259 Materials & Resources Regional Materials Non-potable Water Source Water Water efficient Fixtures Natural Ventilation Energy Efficiency Energy Monitoring Building Efficiency Sustainable Building 2013 Hong Kong Regional Conference Category Credit Request Goal Related Credit At least 70% energy saving compared to the 1980s million tons building energy saving standards (satisfies the CO 2 emission LEED energy saving requirements; Recommended reduction during Energy modeling software includes: PKPM, the building life equest, DeST, IES, Energyplus) cycle. Residential Building: energy saving at least 65% (use geothermal heat pump system), calculated by PKPM Energy efficiency & Low Carbon Pre-requisite1: Fundamental Building Efficiency Design Public Building: energy saving at least 62% (use geothermal heat pump system), calculated by PKPM. Every public building (>20,000m 2 ) must install energy monitoring and control system. Residential building must install sub-meters to monitor the electricity, natural gas and portable water usage; Public building must have sub-meters for HVAC system, lighting, receptacle equipment and natural gas usage. The area of operable window must be at least 5% of the total building gross area, Energy monitoring and control system recovers 100% public constructions, and also monitors the energy consumption of each area. 100% residential buildings have natural ventilation. Energy efficiency & Low Carbon Pre-requisite 4: Sub-metering and Management Thermal comfort Pre-requisite 3: Operable Windows All the building must install water-efficient fixtures in the development area. 62,000 tons CO 2 emission reduction during the building life cycle, million tons water reduction. Water Efficiency Prerequisit1: Water-efficient Fixtures Residential, commercial/public buildings use nonpotable water for irrigation. 67,000 tons CO 2 emission reduction during the building life cycle, million tons water reduction. Water Efficiency Credit1: Non-potable Water Source Use a minimum 60% of the combined weight of construction materials that are extracted, harvested, or recovered, as well as manufactured regionally within a radius of 500km. Use the building materials and products that are extracted and manufactured regionally within a radius of 500km, contributes to CO 2 reduction during the transportation activities. It s estimated 148,000 tons CO 2 emission reduction during the building life cycle in the development area. Materials & Resources Prerequisite 2: Regional Materials 7

260 Pollution Control Construction Environment Renewable Energy Solar Hot Water Geothermal Heat Pump System Daily-Life Waste Waste Management Construction Waste Sustainable Building 2013 Hong Kong Regional Conference Category Credit Request Goal Related Credit Provide an easily accessible dedicated area for Green collection and storage of the construction waste, at Construction & least 80% of construction waste must be recycled, Operation materials include at a minimum metal, brick, wood Prerequisite1: and plastic. Sort and recycle the construction waste, which contributes to CO2 reduction. It s estimated 1.51 million tons CO 2 emission reduction during the building life cycle in the development area. Waste Management Every 20 households install a central garbage collection facility and every 100 households set up a waste sorting and collecting room in the residential community. At least 40% of the total life waste is sorted and recycled in the residential community, which can reduce 5,694 tons CO 2 emission annually. Green Construction & Operation Prerequisite 2: Waste Sorting & Disposal Set up an energy center for district cooling and heating in development area, and all the buildings must connect the geothermal heat pump system from the energy center million tons CO 2 emission reduction during the building life cycle. Energy efficiency & Low Carbon Pre-requisite 4: District Cooling & Heating Install Solar hot water system on the feasible building of the development area million tons CO 2 emission reduction during the building life cycle. Innovation in Design Credit1: Renewable Energy Develop different pollution control plans, such as water and soil erosion control, noise and light pollution control.. All the construction sites must have pollution control plan to ensure the daily life of the residents nearby is not disrupted. Green Construction & Operation Pre-requisite 3: Construction Environment Management Notes:Building life cycle is considered at 50 years; As a conclusion the energy performance of the buildings was set to achieve 70% reduction based upon the China based comparator of CONCLUSION There is undoubtedly a requirement by both local and international developers to address the question of sustainable design and we see this in many areas of our business and more frequently these days. Equally there is an increasing requirement for designers to have a wider understanding of how such measures may be implemented into designs with surety of performance and cost efficiency. The introduction that is now mandatory in many other countries or will be so soon is an initiative that will happen, we just need to be proficient at using this design tool competently as an integrated solution finder. Multi-disciplinary teams that can efficiently integrate are essential for the success of sustainable buildings Note: The views expressed in this manuscript are those of the author and do not necessarily represent the views of AECOM. 8

261 ENERGY CASCADE IN RECENT ZERO CARBON/ENERGY DEVELOPMENT Wai-Ho LEUNG 1, Dr. Raymond YAU and Dr. Vincent CHENG Building Sustainability Group, Arup 1 Corresponding Author wai-ho.leung@arup.com, Tel: (852) , Fax: (852)

262 ENERGY CASCADE IN RECENT ZERO CARBON/ENERGY DEVELOPMENT ABSTRACT In today s world, few will doubt that climate change is our greatest challenge. It is a problem so immense that it can radically alter our world and the way we live in it. In the last few decades, developers have been actively engaged in applying innovative ideas in low to zero carbon building projects that aims to reduce emissions and mitigate global warming; from the Beddington Zero Energy Development, UK Kingspan Lighthouse, Korea Green Tomorrow, to recent HK CIC Zero Carbon Building. Those developments are adopted the similar concept Energy Cascade. We lined up the energy use in terms of their grade, and constructed a system such that the lower grade energy output of one piece equipment, becomes the input for another. This paper focuses on the innovation in energy cascade concept from recent zero carbon/energy development in Hong Kong. Keywords: Zero Carbon, Zero Energy, Energy Cascade, Combined Heating, Cooling and Power, Bio-diesel tri-generation 1. INTRODUCTION From the inventory of Kyoto Protocol to the United Nations Climate Change Conference 2009, commonly known as the Copenhagen Summit, the climate change and carbon emission reduction keep a hot topic over the world. Buildings and Premises consume large portion of carbon emission over the long building operation life. In the last few decades, developers, architects, planners and engineers have been actively engaged in applying innovative ideas in low and zero carbon building projects that aims to reduce emissions and mitigate global warming. This paper focuses on the innovation in energy cascade concept and provides a case study on the application of trigeneration system and the challenges. 2. IMPORTANCE OF ENERGY CASCADE AND ITS PRINCIPLE Based on the first law of thermodynamics energy is not destroyed, just becomes lower grade when used. The energy cascade concept is to line up the energy use in terms of their grade, and constructed a system such that the lower grade energy output of one piece equipment, becomes the input for another. Based on this concept, from building level, we could fully utilize the energy generated from the fuel source with different strategy. Also from utility level, application of energy cascade concept could also significantly reduce the carbon emissions from primary energy source. In Hong Kong, electricity consumed is mainly generated by fossil fuel, coal with portion of natural gas and renewable source connected to mainland. The coal fire power not only cause air pollution problem but also cause inherently inefficient of primary energy source use due to the high-rate of heat rejection. Generally, only 40% of the source energy is captured. The thermal energy from the combustion of fuel is captured in an energy cascade 2

263 concept that first utilizes the highest grade heat for electricity generation, then recover the waste heat for other usages which could potentially capture over 60% of the fuel energy from primary energy source. A case study showing the application of energy cascade concept is discussed in the later section. Figure 1: Energy Cascade Concept 3. CASE STUDY OF ENERGY CASCADE CONCEPT IN HONG KONG 3.1. PROJECT BACKGROUND In response to the quest of low carbon technologies applicable to Hong Kong, the Construction Industry Council (CIC) commissioned the design and construction of a ZCB in Hong Kong in The purpose of the buildings is to create a place for the industry to demonstrate the technologies of the construction and practices of building design and construction. The CIC ZCB has designed with various uses to engage the professionals and practitioners for a common goal of creating a better, safer and more sustainable environment to the industry. The ZCB features more than 80 sustainable installations. The architectural outlook design is shown Figure 2. The construction was completed in June Figure 2 Image of Construction Industry Council Zero Carbon Building 3

264 3.2. CARBON NEUTRALITY The CIC ZCB has its mission in carbon neutrality. Four primary strategies of the stepby-step energy management concepts with over 80 energy conservation strategies to achieve zero carbon emission are listed as follows: a. Identifying the local context, baseline and best practices A critical step in identifying viable solutions; preliminary targets and potential technology are specified at this stage. b. Demand controls - Application of passive design strategies to reduce demand on some architectural integrated design approaches including high performance facade, air tightness, external shading provision, building orientation etc c. Efficient use of Energy - Design of active energy efficient system on MEP design by application of high efficiency system, Thermal recovery, daylighting control, etc d. Renewable energy source - Use of on-site Renewable Energy to overcome the residual energy demand, i.e. photovoltaic system, solar thermal and the key energy cascade technology Bio-fuel Tri-generation System Figure 3 Zero Carbon Hierarchy Items to be considered first should be the low-cost and highly-effective measures the so-called, low-cost, low hanging fruits passive design strategies. Good passive strategies are expressed in the architectural design, they do not require involved operation and can enhance the reduction in artificial lighting, cooling, heating and costs under a large range of conditions. To successfully incorporate passive design, a thorough understanding of the local climatic conditions is required, such that the natural flows and forces can be utilized to enhance the performance of the building. Some strategies are incorporated in the ZCB including high performance envelope, green coverage and green walls, cross-ventilation and high volume low speed fans, automatic windows and user control, microclimate monitoring, natural lighting and light tube etc. Passive design should be followed by careful consideration of the building design to minimize energy use, and the selection of energy efficient systems. The key challenge in implementing active systems is the seamless integration of a large number of interacting energy efficient technologies including the underfloor air-supply, radiant system and desiccant dehumidification, task-lighting and occupancy control, active skylights, low energy office equipment etc. 4

265 By modeling of energy consumption of ZCB, the estimated Energy Use Intensity of ZCB is about 86 kwh/m2 which is about 45% lower than the local Building Energy Code (BEC) compliant baseline building. To further reduce the remaining irreducible energy demand to obtain carbon neutral, on-site renewable source should be adopted. We applied the idea of energy grading to match renewable energies to the remaining energy demands. Apart from the PV and solar thermal system, the innovation of energy cascade concept Tri-generation plant adopted with renewable source of bio-fuel plays a crucial role for carbon neutrality which offset the remaining energy consumption. Figure 4 Snapshot for selected energy conservation strategies 3.3. APPLICATION OF ENERGY CASCADE CONCEPT The 100kW biofuel tri-generation system as a renewable fuel for normal operation is firstly adopted in Hong Kong. It is the combined cooling, heating and power plant (CCHP) that supply space heating, cooling and electricity to ZCB. The high grade heat from combustion of biofuel is first used for electricity generation in an internal combustion engine. Then, the lower grade waste heat from this process is then used in the adsorption chiller for chilled water production. Finally, the remainder energy is used to regenerate the silica in a desiccant dehumidification process. Analogous to the heat strategy, the cooling strategy also runs in a cascade concept. Hot external air is first cooled by the earth as it passes through the earth cooling chamber. It is then dried by the desiccant wheel, before being cooled by the high temperature chilled water coil. The return water from the coil is then used again in the radiant ceiling system to ensure every last drop of cooling energy is extracted. Figure 5 Energy cascade concept applied in CIC ZCB 5

266 3.4. BIODIESEL TRI-GENERATION SYSTEM COMBINED COOLING, HEATING AND POWER The biodiesel tri-generation system is the beating heart of ZCB on zero carbon strategy. It is also a core technology that leads to the energy cascade concept. This technology refers to the simultaneous generation of electricity, heating and cooling in an energy cascade from the combustion of fuel source. Combustion occurs in the Internal Combustion engine driving the pistons to generate electricity. A water jacket cooling system surrounds the engine block to prevent overheating and also as a source of waste heat capture. In addition a high efficiency chimney economizer further increase waste heat capture through recovery through flue gas. The waste heat will be first utilized for driving an absorption chiller to generate chilled water, with the remainder lower grade heat used for dehumidification (in the regeneration of desiccant at heat wheel). Under this energy cascade, 70% of the fuel energy is captured, as compared to 30% in conventional electricity supply. Figure 6 Biodiesel Generator (Left); Adsorption Chiller (Right) After 4 months of operation, the biodiesel tri-generation system is able to produce 1MWh per day, offsetting 0.7 tonnes of carbon. The waste heat captured is also able to generate 20 tonnes of cooling, sufficient for 50% of the A/C period (30% of maximum load). After the building is fully commissioned, it is expected to consume approximately 130 MWh of energy each year (~ 70kWh/sqm/yr for building related energy), while on-site renewable are expected to supply approximately 230 MWh of electricity per annum, of which 100MWh will be exported to the public grid. Not only will the operation of the building be zero carbon, the energy export will also offset over 1000 tonnes of CO2 over its 50 year life-cycle approximately equivalent to the embodied carbon within its major structural components. 4. CHALLENGES OF TRI-GENERATION SYSTEM APPLIED IN HONG KONG The application of tri-generation technology and is still limited to Hong Kong development. There are still many barriers must be overcome for this technology. This began with lots of design considerations, practical, legislative and technical difficulties occurs during the application: 4.1. STRATEGIC LEVEL a) Connection with power utility: When applying the tri-generation plant, it could not be avoided that the issue of imbalance or excessive power generation under fluctuation of power demand in buildings. In some cases, the exceeded amount of 6

267 electricity will be stored by battery and discharged for peak demand period. However, energy loss would be occurred during storage and discharge period through cables and wiring and also the capacity and physical size of battery is mainly depended on the amount of power generation which may not be suitable for medium to large power plant. Grid-connection is a possible way to utilize the exceeded power. The Electrical and Mechanical Services Department published the technical guideline on Grid Connection of Small-scale Renewable Energy Power Systems in 2005 which describes the application procedure to obtain power company's consent to connect a user-constructed small-scale RE power generation system to the grid. The power quality, harmonic, power cut-off time should be specified to ensure that it met the grid-connection requirements. b) Energy Trading Market: Surplus of power back to the grid would come up with the growth of energy trading market. However, this trading market in Hong Kong is still under developed. For example, there is not actual cost benefit or carbon certificate provided by two power companies if the owner surplus power back to the utility grid. More sophisticated energy trading process should be developed in future DESIGN AND APPLICATION LEVEL a) Environmental Impact: The energy generation of tri-generation system is based according to combustion process. Improper design of chimney and flue gas emission will cause high environmental impact. There are some relevant regulatory and environmental requirement from Environmental Protection Department should be considered. b) Fuel Source: Different fuel sources of tri-generation system available in Hong Kong such as diesel oil, town gas and biodiesel. The supply and stability of supply volume sources should be determined during the design. Also, the storage of some fuel source type may be classified as dangerous goods that need to apply for approval by Fire Services Department. c) Integration of systems and control strategy: Tri-generation system is the combined system that is connected to the heating, air conditioning and electrical supply system. The characteristics of each component should be carefully studied and designed in order to identify how best to integrate them into a robust system. The tri-generation system also works together with conventional electric chiller to provide cooling. Comprehensive chiller plant control strategy should be developed to optimize chiller operation sequencing so as to achieve high system efficiency and ensure cooling performance in fast response time. 5. CONCLUSION The energy cascade concept is strategic method on how we utilize the energy source effectively and it is well applied in the first zero carbon building in Hong Kong. Trigeneration system is the core technology applied for energy cascade and some design considerations and challenges for Hong Kong situation has been discussed. 7

268 REFERENCES Electrical and Mechanical Services Department, 2005, Technical Guideline on Grid Connection of Small-scale Renewable Energy Power Systems The Hongkong Electric: Connecting Renewable Energy Power System to Grid Electrical and Mechanical Services Department, Code of Practice for Energy Efficiency of Building Services Installation. Environment Bureau, Hong Kong s Climate Change Strategy and Action Agenda. 8

269 GREEN TRAVELLING STAYING IN SUSTAINABLE HOTEL NGAN Siu Tak, Emil and CHAN Wai Ping, Sammi Yau Lee Construction Company Limited, Hong Kong LEUNG Yan Wah, Esther Biology & Chemistry Department, City University of Hong Kong, Hong Kong 1

270 GREEN TRAVELLING STAYING IN SUSTAINABLE HOTEL ABSTRACT It is generally perceived that development is associated with economic growth and increased energy consumption. Whilst metropolitan cities like Hong Kong would aim to strive towards development advancements, considerations should be made on the adverse impacts caused due to increased energy consumption. The Holiday Inn Express Hong Kong SoHo Project is used as an example to illustrate such an achievement. The Project adopted numerous innovative features and technologies in energy savings and environmental friendly features in its design, including automatic curtain system, photo sensors, energy efficient lighting, airconditioning optimization, counterweight optimization, chilled headboard, etc. The building s entire life cycle has been thoroughly considered prior to construction in creating a comfortable and sustainable building for guests and visitors. As a result, the hotel achieved more than 50% annual energy saving over the half year s operation when comparing to the EMSD s Energy Consumption Indicators (2007) due to the implementation of energy efficient features. Besides the building s architectural design, the execution of the construction process was considered prior to the actual construction. The adoption of these green planning and features led to the Project to receive Platinum awards in both LEED and BEAM Plus, and Provisional Platinum award in BCA Green Mark of Singapore, it was also the recipient of the Merit Prize for Green Building Award 2012 and also Intelligent Building Award in The Project has become an iconic landmark in the green building industry and demonstrates that with the combined effort of the developers, architects, engineers and consultants, the generally higher energy consumption in hotels can in fact also be significantly reduced. With the implementation of green planning and innovative approach, the project could be executed in a sustainable fashion whereas promoting corporate responsibility at the same time. Comment [e1]: Combined used for many parties, joint for only 2 parties 2

271 INTRODUCTION The Holiday Inn Express Hong Kong SoHo is situated amidst the heart of the commercial center in Hong Kong. The project commenced in 2009 and opened in September 2012, being managed by the InterContinental Hotels Group (IHG). The project site is m 2 with a total Gross Floor Area (GFA) of approximately 9,200 m 2. It consists of 36 storeys comprising main lobby, restaurant with podium garden, back-of-house area, 274 guest rooms and function rooms. The project has successfully obtained LEED-NC Platinum in March 2012, which is the first New Building, the first High-Rise Building and the first Hotel to achieve such accreditation in Hong Kong (USGBC, 2013). It is the first project in Hong Kong to achieve BEAM Plus New Building Platinum and Singapore Green Mark s Provisional Platinum (Building Construction Authority, 2013; HKGBC, 2013). This is the first building in the world to achieve Triple Green Building Platinum awards (Lee, 2013). Moreover, the building received the Merit Prize for the Hong Kong Green Building Award 2012 and is also the recipient of the Asian Institute of Intelligent Buildings (AIIB) s Intelligent Building Award 2012 (Green Building Award, 2012). 1 ARCHITECTURAL ASPECTS Consideration was made on the building s architectural design. The window area of the building was minimized in the West where the highest heat load is received in this direction. By reducing the amount of heat load entering the building, the demand for air-conditioning is significantly reduced, thus lowering the energy consumption. A green wall was installed from 2/F to 6/F and together with greenery at the podium garden and the rooftop, the total landscaping area equals to 47.5% of the site area. It could minimize the heat island effect by reducing the heat absorbed at the building façade. Large glazed windows are implemented at the lift lobbies to maximize the amount of natural light entering the building. An open staircase was installed with no window glazing, allowing natural ventilation and lighting into the staircases, thereby contributing to energy saving. The guest rooms are located at the North and South directions to optimize daylight harvest and view, and Insulated Glass Unit (IGU) with low-emissivity coating is adopted for the curtain wall to provide better insulation against additional heat entering the building. In addition, motorized roller blind system is installed in all hotel guest rooms, which is connected to the key card system. When guests enter the hotel rooms and insert the key card, the roller blinds would be raised automatically. As the guests leave the room and remove the key card, the roller blinds will be drawn down to prevent sunlight from entering the building, which can reduce the cooling load of the building. Time control has also been set on the roller blind system to be drawn down by itself to minimize light pollution to the neighboring buildings. Comment [e2]: Replaced as reduce and reducing in same sentence 2 STRUCTURAL ASPECTS The design team took into account the structural aspects of the building in terms of the amount of materials required for the building envelope. A wind tunnel modeling study was conducted on the building to determine the actual amount of materials needed to support the structural loading of the 36-storey hotel while fulfilling local regulations set by the Buildings Department. The study concluded that 45 tons of reinforcing steel could be reduced from the original design, thereby saving resources. On the other hand, the building components are standardized for the guest room floors, whereas precast façade and off-site fabricated components such as staircases are used which reduce the amount of construction waste generated at the site, labor costs and the amount of air pollutants generated if components are fabricated on-site instead. 3

272 3 ELECTRICAL AND MECHANICAL ASPECTS Much effort has been made on the electrical and mechanical (E&M) design of this project, and are divided into 5 major aspects: 1) Heating, Ventilation and Air- Conditioning; 2) Electrical; 3) Lifts; 4) Plumbing and Drainage; and 5) Innovative Technologies. 3.1 HEATING, VENTILATION AND AIR-CONDITIONING SYSTEMS Water-cooled chiller with a Coefficient of Performance (COP) higher than both local and international regulations is implemented, implying that the selected chiller can generate air-conditioning more efficiently than conventional ones. Variable Speed Drive (VSD) controls are installed at the system s chiller, cooling tower fans, condensing water pumps and chilled water pumps. VSD controls are used to provide variable flow for the chilled water system depending on the building demand throughout the day to optimize energy consumption on air-conditioning. Apart from the water side system, the air side system s primary air handling unit is coupled with CO 2 sensors so that the amount of air entering the area will be adjusted based on the CO 2 concentration detected. The concentration of CO 2 is a measure of occupancy inside the building; thus when CO 2 level increases, it means that the area is occupied and fresh air would be drawn in accordingly to meet the needs and comfort of the occupants. The air flow is additionally controlled by the volume control dampers at the air ducts of the fan coil units to optimize the amount of air-conditioning, ultimately saving energy. The building has also set up a Building Management System (BMS) where controls on HVAC, lighting for common areas, fire services and plumbing services are centralized. The BMS is monitored and controlled by the facility management, so that when there is any system malfunction, signals and alarms will be generated from the BMS for operators to take appropriate action. 3.2 ELECTRICAL SYSTEMS For the electrical system, energy efficient lighting fixtures such as Light-Emitting Diode (LED) lights, which have longer service life than compact fluorescent lamps are installed. T5 light tubes with high-efficiency electronic ballasts are installed in the building to reduce energy consumption. Daylight sensors are installed at the lift lobbies where unnecessary lighting can be turned off when natural light is adequate in order to save energy. The staircases are provided with minimum lighting to meet and comply with the local regulations. Solar lawn lights are placed at the rooftop to harvest and store solar energy in nickel cadmium batteries inside the lamps. The charged batteries are then being used during the night. In addition, over 98% of the energy appliances adopted in the hotel that are eligible under the Electrical and Mechanical Services Department s (EMSD) Voluntary Energy Efficient Labeling Scheme are with Grade 1 or 2 Energy Labels. 3.3 LIFT SYSTEMS There are four passenger lifts implemented in the hotel and have energy-efficient features. The lifts motors are driven under Variable Voltage Variable Frequency (VVVF), where alternating current is first turned into direct current before converting back to alternating current with variable amplitude and frequency (EMSD, 2000). VVVF motor drive requires almost 80% less starting current than the conventional lift motors (EMSD, 2000). In hotels like the Holiday Inn Express Hong Kong SoHo, the passenger traffic varies throughout the day, with long periods of idling time. When the lifts are idled for more than 15 minutes, the lighting and ventilation of the lift cars would be switched off and undergo sleep mode to reduce unnecessary energy consumption. Moreover, an optimization technique was conducted by researchers on the lift s counterweight. A counterweight is like a balance against the lift car which is normally 50% heavier than the lift car itself (Lam et al., 2006). It was found that when the counterweight is adjusted to 35% heavier than the lift car, more than 13% can be saved 4

273 on lift energy consumption while maintaining the safety standards as required by local regulations (Lam et al., 2006). 3.4 PLUMBING AND DRAINAGE SYSTEMS The hot water system for this building uses heat pump coupled with solar energy to generate hot water supply. In a conventional building, boiler is used to generate hot water. In replacement of the boiler, rejected heat from the air-conditioning plant is recycled through the return chilled water. On the other hand, solar panels are installed on the upper roof and solar reclaimed cladding is embedded into the façade on the top floor to harvest solar energy. Together with the reclaimed heat from the HVAC system, the combined energy is utilized by heat exchanger to pre-heat the cold water for general usage. This system saves the most significant amount of energy in this project. Rainwater collection system is implemented in this project by collecting and treating the rainwater on the roof and podium garden. Also, condensate water from the building s air-conditioning system is collected and treated using carbon filter and ultraviolet lamp to remove suspended solids before re-used for irrigation purposes. Moreover, the water fixtures installed in the building are water-efficient, including shower heads and faucets added with regulators, dual-flush water closets with low capacity flushing and water efficient washing machines at the laundry room. 3.5 INNOVATIVE TECHNIQUES A number of innovative techniques have been introduced in the building, one of them being the lift counterweight optimization which has been discussed previously. Another innovative technique is called intelligent fan coil unit (ifcu). Unlike the conventional fan coil unit which uses alternating current motor, ifcu uses direct current motor through magnetic forces to operate. The power consumption of ifcu can be reduced by as much as 80%, and the motor s operating temperature rise can be reduced by at least 50%. On top of that, ifcu can be self-adjusted in each guest room to provide better thermal comfort to the individual needs of the hotel guests. An innovative technique is incorporated at the top two guest floors as a showcase and experiment, which is the Chilled Headboard. This technique is similar to a personalized air-conditioner embedded into the headboard of the beds. During sleeping hours, the timer-controlled headboard generates cool air and the ifcu which is linked up with the headboard would be adjusted to low speed. The room temperature can be raised from 24 C to 27 C without affecting the guests comfort by adopting Chilled Headboard. This technique s objective is to reduce the amount of energy consumed by cooling down the entire guest room when guests are sleeping. In addition, a pattern recognition technology is being introduced, coupling closed-circuit television (CCTV) cameras with motion sensors to observe the occupancy status of the corridors. When body movement is not captured, lights would be dimmed and air-conditioning would be adjusted to reduce energy consumption. Finally, an energy management analysis software is used to log real-time data, which can be used to monitor, analyze and optimize the building performance during operation. 4 MATERIALS ASPECTS Greener and sustainable building materials are adopted in the building. All sealants and adhesives, paints and coatings contain low Volatile Organic Compounds (VOC) content to enhance the indoor air quality. All timber products purchased are from sustainable sources, including doors, wood panels, furniture and temporary timber works. The timber decking located at 2/F s podium garden is made from recycled timber as well. The refrigerants used in the project do not contain chlorofluorocarbons (CFCs), which was found to be associated with global ozone depletion and cause adverse impacts to the environment as indicated during the Montreal Protocol (Morrisette, 1989). 5

274 5 CONSTRUCTION ASPECTS During construction works, monthly environmental monitoring was conducted on air quality, noise quality and water quality to ensure pollution does not exceed the local standards. Vehicle wheels were washed prior to entering and leaving the construction site whereas materials that could generate dust were covered to minimize air pollutants. Building Information Modeling (BIM) was applied while constructing the building s façade and underground utilities. It is a software that can integrate layers of materials to detect any overlapping problems and also allows for correction. By adopting BIM in the project, it enhanced site safety, communication while saving construction time and avoiding unnecessary defaults in construction works. Moreover, construction wastes were sorted on-site before disposal, to encourage materials reuse and recycling. Comment [e3]: Present tense as these abilit are current Photos of the green features implemented in this project are illustrated below: 6 CONCLUSION To summarize, Holiday Inn Express Hong Kong SoHo took consideration in energy savings and environmental friendly features during the preliminary design, from architectural and structural planning to construction and operation. The building s entire life cycle was considered in creating a comfortable and sustainable building for guests and visitors. It has also become an iconic landmark in the green building industry and demonstrates that with the combined effort of the developers, architects, engineers and consultants, the generally higher energy consumption in hotels as compared to other building types can in fact also be significantly reduced. 7 REFERENCES Building Construction Authority, Available from: [Accessed 30 May 2013]. Electrical and Mechanical Services Department, Guidelines on Energy Efficiency of Lift and Escalator Installations, Available from: [Accessed 30 May 2013]. Green Building Award 2012, Available from: [Accessed 1 June 2013]. Hong Kong Green Building Council, 2013, Available from: [Accessed 29 May 2013]. Lam D.C.M., So A.T.P and T.K. Ng, Energy Conservation Solutions for Lifts and Escalators of Hong Kong Housing Authority, Elevator Technology 16, Proceedings of 16 th World Congress on Elevator Technology, IAFE, Helsinki: D. Lee, Passion Drives World s First Triple-Platinum Green Hotel. Available from: [Accessed 21 April 2013]. P.M. Morrisette, The Evolution of Policy Responses to Stratospheric Ozone Depletion, Natural Resources Journal, 29: U.S. Green Building Council, Available from: [accessed 30 May 2013]. 6

275 Hysan Place Innovative environmental solutions to urban density Hysan Place in Causeway Bay, at one of the busiest and most expensive locations in the world, found innovative solutions to environmental problems of high density, and happily married green initiatives with commercial success. With 15 floors of Grade A offices and 17 floors of retails, totaling 710,000 sq. ft., it is the first LEED-CS platinum and Beam Plus platinum mixed-use vertical mall in the world. Despite of its limited size, it manages to integrate many uses under one roof giving its users excellent convenience and connectivity. Offices, shops and its anchor tenants are expressed individual boxes with different identities stacked into an interesting massing and interconnected by lifts and escalators. Between these boxes, openings are carved to create "urban windows" that encourage urban ventilation and alleviate problem of pollution in the canyon of streets lined with high rise buildings. These openings also make the building more permeable to eye and break the continuous wall of building frontages. These urban windows form semi external spaces for various uses at different levels. At podium level, the 3-storey high opening becomes a sky garden that provides community with a green oasis right in the heart of a busy shopping district. Above the building boxes, the main roof is turned into an urban farm that allows city dwellers to squeeze organic farming into their busy working life. The roof above the retail floors is being turned into an artificial wetland where an academic institution can test out biological treatment of grey water in an urban high rise setting. Being a vertical development which renders the use of renewable energy device difficult, it is carefully designed to take advantage of good planning and passive devices to minimize energy intake and optimize the use of natural or mechanical ventilation both in office and retail floors. 7 June 2013

276 Performance Synergies in Small Urban Zones Nils Larsson, International Initiative for a Sustainable Built Environment (iisbe) Salat, Serge, Urban Morphology and Complex Systems Institute, Paris Bourdic, Loeiz, Urban Morphology and Complex Systems Institute, Paris 1

277 Performance Synergies in Small Urban Zones Abstract This document outlines a systems model for small urban zones to maximize operational efficiencies by optimising supply, demand and storage functions of energy, potable water, greywater, materials and local transportation systems associated with multiple buildings and community services. Keywords: Energetic Urban Planning, Building clusters, Urban Neighbourhoods, System synergies; Thermal energy; greywater; DC power 1. Introduction In the developed world, communities are facing massive costs to renew ageing infrastructure under conditions of a weak economy, while a large portion of communities in the developing world are seeing rapid growth outpacing their ability to expand using traditional infrastructure models. At the same time communities in both the developed and developing world are under increasing pressure to become much more sustainable and competitive in an increasingly globalized economy. Some of the barriers to improved building performance that remain are due to the limitations on what measures can be taken within a single building and a single building type. For example, it will always be more difficult to reach nearly-zero energy performance in an office building than a multi-unit residential building, because of the functional requirements of office buildings. Conversely, residential buildings will always consume more water than office buildings, because of the water-intensive nature of residential activities. Considerable performance improvements can be achieved if use is made of the varied characteristics of a cluster or group of different buildings located in close proximity. Factors that make some of these synergies possible are shown below for residential, office and school buildings. Issue / System Residential Office w. interior zone Space to install PV or thermal solar collectors (orientation issue not considered) Space heating (heating season) In low-rise, space for large arrays on roofs. 2 Roof or ground installation is problematic, and spandrel panel types are expensive. Thermal surplus from interior zones School Space for large arrays on roofs. Energy deficit for space heating Variable, depending on student density Domestic hot water High constant demand Low demand Low and intermittent demand Rainwater collection for use Good possibilities in Could have surplus in lowrise Surplus is likely due as greywater low-rise family projects projects, but deficit in to large collection (if there is storage and more with open landscaped high-rise. area on roof and than 500 mm/yr. rain) areas and flat roofs grounds. Vehicle parking Night-time peak demand Day-time peak demand Day-time peak demand Figure 1: Overview of relationship between selected generic building types The table shows, in a very generalized way, the fit between generic building type and various system types and indicates that, in many cases, buildings with deficits in energy,

278 water, or even parking spaces, could be supplied by other buildings with surpluses, sometimes concurrently and sometimes at different times. Small urban zones also have open spaces of various types (parks, parking lots) that provide other possibilities for rainwater harvesting or locations for PV arrays. Obviously, more specific observations depends on specific building locations and designs. 2. Moving Towards Zero Carbon in The Netherlands Recent work carried out in Rotterdam, Amsterdam and other Dutch locations, has shown the considerable potential for reductions in energy, water and material consumption. The initiatives are based on three separately developed methods: Energy Potential Mapping, the New Stepped Strategy and the Rotterdam Energy Approach & Planning. The Energy Potential Mapping method was developed to integrate knowledge of potential energy sources within an area, in horizontal sub-surface layers The method uses GIS mapping, with data based on topographic, geophysical and infrastructure information. The method can produce maps that show the potential for renewable fuels, power generation and thermal potentials. The New Stepped Strategy is an outgrowth of the well-known Trias Energetica (Lysen, 1996), which posited a stepped strategy to reduce energy consumption. This approach became influential over the last decade amongst European designers, probably because of its simplicity and logic. 1. Reduce demand (review program requirements, use passive solar approach 2. Use renewable energy 3. Supply the residual demand with very efficient systems The New Stepped Strategy was proposed by Dobbelsteen in 2008 as a replacement for the Trias Energetica. Dobbelesteen s proposal was based on his observation that Step 2 (use of renewables) was under-used, leaving too much emphasis on step 3, the use of efficient fossil-based systems. The NSS approach eliminates Step 3 (the efficient use of fossil fuels), on the assumption that the residual energy needs can be fully met by renewable energy sources. This is made possible by a new Step 2, reuse of waste streams, where waste includes waste heat, water and material. A final proviso (3b) is that any truly residual waste must be benign enough to be returned to nature. Figure 2: Steps in New Stepped Strategy (Dobbelsteen 2008) 3

279 The Rotterdam Energy Approach & Planning (REAP) applied the NSS approach to real urban problems at scales ranging from buildings, clusters of buildings, neighbourhoods, districts, and the city. A key concept is that supply and demand is balanced at higher scales before energy generation is considered. This approach also implies efficient storage and control systems. The relationship of the REAP scalar approach to the steps in the New Stepped Strategy can be seen in the diagram below. Figure 3: Relationship of REAP scalar approach with steps proposed in the New Stepped Strategy (adapted from Dobbelsteen, 2011) In the Rotterdam Hart Van Zuid case study, Tillie et al. (Tillie et al. 2009b) apply the REAP method to a whole district, by optimizing 4 clusters (neighborhood scale): Zuidplein cluster, Ikazia cluster, Motorstraat cluster and Ahoy cluster. For each cluster, the method aims at reducing the overall energy needs of the cluster, using a stepped strategy. The first step consists in inventorying the energy consumption at the cluster scale. It also aims at adding new functions (shops, supermarkets, leisure infrastructures ) in order to balance the heat:cold ratio. A building office for instance requires cooling most of the time. But to cool a given amount of air, any air conditioning system produces an equivalent amount of hot air. This heat is currently wasted in most of the buildings, whereas it could be reused by other buildings that require heating instead of cooling (housing for instance). Tillie et al. inventory a wide range of buildings, with different cooling/heating needs patterns: housings, offices, shops, supermarkets, ice rinks, swimming pools, etc. The need for cooling or heating of these buildings changes throughout the day and the year. With an adapted mix of buildings (a heat : cold ratio close to one) and heat/cold storage infrastructures, the heat/cold waste streams could be reused. With a perfect mix 4

280 (heat:cold ratio equals one) and appropriate heat/cold storage systems, this process could theoretically lead to a 50% reduction in energy consumption for heating and cooling: as all the heat usually wasted by cooling systems is reused, heating is free. Tillie et al s detailed case study shows that significant reductions (up to 44%) could be achieved just by an appropriate mix of buildings, heating/cooling requirements, and heat/cold storage facilities at the neighborhood scale. Further investigations have to be made to analyze the dynamic of such heat transfers, and the possibilities of heat and cold storage, to confirm the potentialities of such an approach. In applying the Dutch experience to other regions, care must be taken to consider the probable supporting role of the temperate Dutch climate in achieving the positive results reported. 3. Smart Grids The work being undertaken in the Netherlands described in the previous section is establishing promising new directions for greatly reducing energy, water and materials consumption by balancing supply and demand and reducing waste. Although here is little activity in Europe or North America to extend this work, there is considerable R&D activity in so-called Smart Grid development, which also seeks to reduce GHG emissions. Smart Grid work focuses on optimising the supply and demand of electricity through the use of storage and smart control systems, and by promoting the use of regional and local sources of renewable power generation. The scale of application of Smart Grid projects tends to be regional, reflecting the leading role of electric power utilities in promoting this work. A smart grid can theoretically collect the optimal amount of information necessary for customers, distributors and generators to change their human and equipment behavior in a way that reduces system demands and costs, increases energy efficiency, optimally allocates and matches demand and resources to meet that demand, and increases the reliability of the grid. The potential social and technical benefits of a smart grid are reduced greenhouse gas and other emissions, lower costs, increased reliability, greater security and flexibility to accommodate new energy technologies, including renewable, intermittent and distributed sources. The issue of GHG emissions is key in driving climate change, and the focus on electrical production goes to the heart of the issue, since commercial buildings in developed countries use the majority of all electrical output, and most electricity is generated in very inefficient thermal power plants. Although we cannot yet identify the scale of energy, emissions and materials savings that may accrue from the introduction of Synergy Zones, we do have some credible estimates related to he implementation of smart grids at a national scale in the U.S.A. The U.S. Department of Energy has sponsored a report (Pratt et al. 2010), aiming at estimating both the energy and CO 2 benefits that the implementation of a smart grid at the U.S. national scale could provide. The robust methodology used in this report takes into account both direct reductions (savings in the end-use energy consumption or reduction in the generation requirements) and indirect reductions (cost savings produced by smart grid functions and reinvested in energy efficiency and renewable resources). By 2030, expected reductions in CO 2 emissions associated to the reductions in the electricity consumption directly due to a U.S. national scale implementation are expected to be up to around 12%, and 6% indirectly. These reductions are very significant, but are not sufficient in the urgent context of climate change mitigation. 5

281 Table 1. Potential Reductions in Electricity and CO2 Emissions in 2030 Attributable to Smart Grid Technologies (Pratt 2010) The authors note that The estimates assume full deployment (100% penetration) of smart grid technologies. Since the reductions are expected to be linear with respect to penetration level, this assumption enables the estimates to be readily scaled to lower levels of assumed penetration. The importance of these reduction estimates is in their combined effect. While several of the mechanisms are estimated to have small or negligible impacts, five of the mechanisms could potentially provide reductions of over 1%. Moreover, the combined effect of the direct mechanisms is 12%, and the indirect mechanisms total 6% of energy and emissions for the U.S. electricity sector. These correspond to 5% and 2% of the U.S. total energy consumption and energy-related CO2 emissions for all sectors (including electricity). The magnitude of these reductions suggests that, while a smart grid is not the primary mechanism for achieving aggressive national goals for energy and carbon savings, it is capable of providing a very substantial contribution to the goals for the electricity sector. 4. Possible New Directions The two previous sections have outlined approaches towards the goal of carbon-neutral urban areas that appear to be somewhat independent. The strategy used in the Netherlands is more comprehensive, since it covers energy, water and materials and at a series of scale levels. It is not clear, however, whether the performance gains The Smart Grid work will undoubtedly pay dividends, considering the funding and intellectual effort going into it, but it does seem that it could benefit from an application at smaller scales and a more inclusive look at the systems involved, building on the work done in the Netherlands. Specifically, there are many other building services beyond electrical power that could create new levels of efficiency and reduction of waste from the optimization of supply and demand, but these cannot be dealt with at a regional scale. If the Smart Grid concept were to be developed at a smaller scale it would be possible to deal with the interaction of a wider range of systems. Some of the neighborhood-scale (zone) systems that could benefit from the Smart Grid focus on optimization of storage, supply and demand, and a reduction in wasted energy and material flows include. 6

282 Thermal energy for space heating or cooling; Domestic hot water; Grey water; Local use DC power at the zone level; Utilisation of solid waste generated by building operations; Synergies in use of vehicle parking facilities for various occupancy types. Each of these urban sub-systems could benefit from appropriate storage systems, controls and algorithms for optimization of supply and demand, and distribution networks. The optimistion of supply and demand of parking spaces is a related issue in view of the large amounts of embodied energy and emissions represented by the construction of unnecessary parking facilities. One aspect that is neglected in both the Netherlands and Smart Grid work is the centrality of questions of property ownership and management control. The development and implementation of these concepts will require a pattern of property control and management that facilitates the integration of individual building systems and operation into the larger local zone. 5. Synergy Zones The Synergy Zone initiative has been developed (Salat 2012) by the International Initiative for a Sustainable Built Environment (iisbe) to address issues of system synergies that are made possible by focusing on small building cluster or neighbourhood areas. We believe that this approach provides a useful and practical synthesis of the Dutch and Smart Grid concepts. A Synergy Zone, as we define it, would include the following elements within a small urban neighborhood (here referred to as a Zone for convenience). 1. The starting point in a new development is to maximize the passive solar performance potential of the buildings in the Zone, individually and collectively. At the level of individual buildings in new zones, this means that the solar access of buildings should be impaired as little as possible, and that the orientation and configuration of each building should maximize its passive performance. Even a zone containing buildings that are sub-optimal in terms of passive solar potential may have a high level of passive performance as a whole if inter-building spaces are tight enough to maintain a high level of density and if they are strategically oriented. These arguments obviously do not apply to existing zones. 2. The Smart Grid proposals we have seen are silent on the topic of space heating or cooling, and the possibility of thermal generation in the zone (GSHP, CHP or biomass), as well as thermal storage in the zone to serve such thermal sources. This is especially logical in the context of some buildings producing a heat surplus (captured through heat-recovery ventilation systems), while others could benefit economically from zone-supplied heat. On the cooling side, some building operators may find it more economical to draw on a chilled thermal source supplied from the zone. We therefore see a need for thermal mid-term storage of thermal generation sources and a re-distribution system of low-temperature heating systems of buildings in the zone that have thermal deficits. Optimization controls and software are essential to optimize such a system. 3. Domestic hot water systems are another candidate for optimisation of supply and demand, given that some occupancies (residential, hotels, restaurants) have high demand, while commercial or public occupancies have little demand, but offer the possibility of DHW production through waste heat produced in combined heat and 7

283 power (CHP) systems or (for DHW pre-heating) recapture of thermal energy from HRVs. 4. Many modern buildings make provision for rainwater capture and grey water use, but some (e.g. highrise) have relatively minimal opportunities for rainwater capture, while low-rise buildings can produce large amounts. There is therefore logic in exploring a zone-wide greywater treatment, storage and redistribution system for all buildings in the zone. Such a system would filter and treat grey and black-water within the zone before storage. Again, optimization controls and software are essential to optimize such a system. 5. A similar case can be made for a zone-wide system for solid waste capture and storage for all buildings in the zone, such as provided by central vacuum systems. Such a system could be linked to a local zone bio-generation plant. 6. The role of DC power generation is dealt with in some Smart Grid proposals, but usually in relation to power contributions by regional renewable energy sources and with respect to use by plug-in electric vehicles. In the restricted area of a Synergy Zone, the source of DC power may include that produced from CHP, PV, wind power, bio-mass or other common renewable source in the zone. Power can also be produced on buildings in the zone that have orientations or configurations suited for solar, which would ensure diversity of supply. The storage of DC power will be an important feature of a Synergy Zone approach, to store power generated in the zone as well as off-peak power from outside sources, for redistribution to other buildings in the zone with a DC deficit. The ability to use DC power in the zone would minimize conversion losses due to the normal conversion to AC for transmission and then back to DC again at the point of use. Of course, as in Smart Grid projects, excess DC power could be converted to AC and exported back to the grid. 7. We also propose to explore the installation of DC power distribution systems in commercial buildings in the zone, operating in parallel with conventional AC systems to directly provide power to low-voltage DC equipment. Such direct use of DC would increase operating efficiencies by reducing conversion losses. The proposal for use of direct DC building systems reflects the greater availability of DC power sources and also the increasing prevalence of DC-powered systems in buildings, such as electronic light ballasts and computer equipment. Such parallel systems would represent a major shift in systems thinking, and would also require that parallel lines of electronic equipment be developed. Another use is DC power for the re-charging of electric vehicles in the zone. 8. The issue of jurisdiction and management is of critical importance in cases where a zone is not under single ownership. Coordinated system implementation and operation within a zone under multiple ownership could easily fail at the beginning unless there are contracts and agreements in place that allow a common management body to build, operate and charge for the required systems. In such cases, the physical implementation of systems, their operation and the revenue and cost sharing will require a new form of cooperative zone management to be successful. 8

284 Figure 4: Schematic representation of a Synergy Zone 6. Scenarios for mixes of occupancy and configuration types within Synergy zones and clusters It is obvious from the nature of Synergy Zones and also from the analysis of Dobbelsteen, Tilley et al, that the mix of occupancy and building configuration (low-rise, high-rise, fat, thin shapes etc.) will greatly affect the maximum level of efficiencies possible. The issues are complicated further when the concept is applied to existing zones, which have a greater diversity of configuration and technical characteristics than new construction. Finally, when the interaction of technical systems at these various scales is considered, the picture becomes still more complex. The total performance gains are likely to vary with the type of zone in the following ways: The location of the zone with respect to wind regimes will affect the viability of wind power generation within the zone, while the potential for geothermal-based heating or cooling will be affected by aquifers and geology; Open space uses (green areas, playgrounds, parking lots) will be good collectors of rain and storm water and may be sites for solar energy systems, but are obviously irrelevant with respect to thermal exchanges; Heterogeneity of building configurations will affect potential. For example, a combination of some low-rise and medium to high rise will enhance potential for 9

285 solar renewable generation and greywater exchanges because of greater roof area in low-rise and more demand with less roof area in higher buildings. Residential and non-residential occupancies will be another factor in performance potential, since residential occupancies have heavy demand for DHW and space heating, while commercial uses typically generate excess internal heat gains; In many cases, older urban neighborhoods may have the best conditions, while areas from 1950 to 1990 may be too homogeneous to be good prospect Zones with heterogeneous ownership may face intractable management issues in implementing the sharing financing and operation of technical services as envisaged. It may be that a new form of high-level partial ownership, somewhat as in condominiums, will have to be developed. 7. Conclusions We have already outlined the benefits that are awaited from the broader application of the REAP principles and the introduction of Smart Grids. We see Synergy Zones as adding additional energy and environmental benefits from the integration of other systems, beyond what is currently planned. Perhaps most important are gains in resiliency, efficiency and quality of service. More detailed theoretical and practical work is needed to test this hypothesis, with a special emphasis on developing solutions for the management issues that are inherent in the concept. 8. References Dobbelsteen A. van den, Jansen S., Timmeren A. van & Roggema R.; Energy Potential Mapping - A systematic approach to sustainable regional planning based on climate change, local potentials and exergy, in: Proceedings of the CIB World Building Congress 2007; CIB/CSIR, Cape Town, 2007 Lysen E.H.; The Trias Energetica - Solar Energy Strategies for Developing Countries, in Proceedings of the Eurosun Conference; Freiburg, 1996 Pratt RG et al., "The Smart Grid: An Estimation of the Energy and CO2 Benefits" U.S. Department of Energy, PNNL-19112, Revision 1, Salat Serge, Bourdic Loeiz, Larsson Nils, Hovorka Frank; Smart and Synergy Grids: the Leaf Versus the Tree, in Proceedings of the Technoport 2012 conference, Trondheim, Norway, Tillie N., Dobbelsteen A. van den, Doepel D., Jager W. de, Joubert M. & Mayenburg D.; REAP - Rotterdam Energy Approach & Planning ; Rotterdam Climate Initiative, Rotterdam, 2009a Tillie N., Dobbelsteen A. van den, Doepel D., Jager W. de, Joubert M. & Mayenburg D.; Towards CO2 Neutral Urban Planning - Introducing the Rotterdam Energy Approach and Planning (REAP) in: Journal of Green Building, Vol. 4, No. 3, summer, 2009b ( ) Van den Dobbelsteen, A.A.J.F and Tillie, N.M.J.D. Energetic urban planning: A novel approach to carbon-neutral cities, paper presented at World Sustainable Building Conference SB11, Helsinki, Finland, October

286 Topic: The Street and the Sustainable City. Name: David Grahame Shane GSAPP Columbia University

287 Abstract Architects, planners and urban designers have used the street as an organizing device since ancient times. Its form mutated over time, changing scale, becoming controlled by the symbolism of scientific, single point perspective and then becoming a scientific instrument of public hygiene, as well as potent symbol of industrial might and modern state power in the modern metropolis. By 1900 the colonial wealth concentrated in European imperial capitals amplified and extended the symbolic dimension of the street, while American cities like Chicago and New York introduced the steel framed skyscraper as a new, commercial and industrial building type producing new concentrations of enormous density. Much of the effort of urban designers in the twentieth century involved adaptations of the traditional metropolitan street morphology to accommodate the skyscraper. These buildings increased density and created new forms of pubic space at the interface between street and tower. Another American invention, the automobile simultaneously set in motion an equal and opposite force, amplifying the network capacity of the early industrial railway system and enabling much more personal mobility, blending town and country in an new peri-urban commuter belt. Highway engineers over the course of the 20th century developed methods of modeling and managing traffic flows, building huge arteries into the city and setting up tree like street hierarchies. These street arteries lead away from and around the center of the metropolis, creating the megalopolis, a linear city stretching over vast city territories, housing tens of millions of people at low densities. This paper explores the interaction of these forces of concentration and dispersal in terms of an altered understanding of current global settlement patterns, future predictions of energy resources, changing climate predictions and the switch from eco-footprint concerns to urban resilience. In its conclusion the paper explores different potential combinations in the city and street section that might enable highdensity cities to be more resilient under current models of ecological and population pressures. Keywords: Density; Desakota; Megacities; Megalopolis; Metropolis; Resilience; Sectional Development; Skyscrapers; Streets.

288 Keynote Presentation Dr Michael Voigt Head of EcoCommercial Building Centre of Excellence China Bayer MaterialScience (China) Co. Ltd. Title: "Case Study of an Energy-efficient Metropolitan Commercial Building" Abstract: The EcoCommercial Building program is comprised of Bayer MaterialScience and a network of experts. In cooperation with its interdisciplinary EcoCommercial Building network Bayer MaterialScience supports building decision makers in the implementation of public and commercial buildings that significantly exceed existing standards of energy saving and sustainability. The program is guided by its far sighted vision of achieving net-zero emission buildings through an integrated design concept and integrated system solutions. Within the frame of its EcoCommercial Building program Bayer already operates several low-energy and zero-energy buildings in different countries and in different climate zones. In China the ECB program set up the 1st zero-emission office building in Qingdao in Continuous performance monitoring during its first one year operational cycle has confirmed the successful realization of the set zero-emission target. In addition to the real cases ECB network partners have worked out virtual and real case studies. As the realization of low-energy buildings and access to renewable energy supply in large metropolitan areas is quite challenging the EcoCommercial Building program's team cooperated with Tokyo University to develop based on an actual building in a downtown area an illustrative case study of a low-energy building incl. the financial implications of its potential realization. The case study shows that the EcoCommercial Building concept is also valid for high density districts and applicable to retrofits of existing building under highly demanding condition of urban centers like Tokyo or Hong Kong.

289 INTEGRATED URBAN ELEMENTS FOR LOW ENERGY, LOW CARBON PERFORMANCE BUILDINGS Mark Richardson 1 and Mark Cameron 2 Arup, Building Sustainability, Hong Kong 1 Corresponding Authors mark-a.richardson@arup.com, Tel: (852) Corresponding Authors Mark.cameron@arup.com, Tel: (852)

290 INTEGRATED URBAN ELEMENTS FOR LOW ENERGY, LOW CARBON PERFORMANCE BUILDINGS ABSTRACT Dense high rise cities such as Hong Kong create unique challenges and opportunities for sustainable buildings. As cities become denser, many systems and processes become challenging or costly to install in buildings. This paper considers how low energy, low carbon buildings can push their own systems to the commercial limit before integrating with cities to achieve greater energy consumption reductions. This paper considers key elements of buildings: Understanding how cost profiling can inform building system choice. Understanding how to predict the commercial limit of technology viability. Integration potentials beyond the boundary of the building. And through looking beyond the boundary of the building: Identify how closed loop design can reduce energy, carbon and waste footprints. Keywords: Energy / cost abatement curve, commercial viability, community energy, closed loop design, HK30/ INTRODUCTION In light of pressing concerns over catastrophic climate change immediate actions to reduce carbon emissions are essential. Figure 1 shows the challenge that Hong Kong faces to contain a temperature rise to 2 o C as purported by Intergovernmental Panel on Climate Change (IPCC) to combat change and have a fair chance of avoiding catastrophic consequences 3. Working alongside the governments proposed supply side measures to reduce carbon emission factors 4 demand side reduction of energy consumption is also required. The buildings of Hong Kong account for around 90% and 60% of Hong Kong s electricity consumption and carbon emissions 5 respectively and as such a heavy responsibility relies on building designers to act in a proper manner to collectively enable a sustained future for Hong Kong and the world. 3 Baer, P. and M. Mastrandrea, 2006, "High Stakes: Designing emissions pathways to reduce the risk of dangerous climate change", Institute for Public Policy Research, 4 Emission factor according to Guidelines To Account For And Report On Greenhouse Gas Emissions And Removals For Buildings In Hong Kong (2010 Edition) by the Environmental Protection Department, HKSAR Government 5 Council for Sustainable Development, 2011, Invitation for Response Document 2011: Combating Climate Change: Energy Saving and Carbon Emission Reduction in Buildings. 2

291 Per Capita Emissions [t/p/y] Sustainable Building 2013 Hong Kong Regional Conference t/p/y In % associated with buildings 6 5 Decarbonizing Electricity RE Introduction of nuclear power Increasing use of natural gas Increasing population, productivity and quality of life 4 t/p/y by t/p/y by 2030 Low Carbon Buildings and Retrofitting Smart Urban Form Active System Passive Design 1 t/p/y by Baer and Mastrandrea 2 degree limit trajectory Figure 1: Interventions To Achieve The 2oC Temperature Rise Limit The Hong Kong Green Building Council (HKGBC), through their HK30/30 plan, proposes an absolute reduction of electricity consumption in buildings of 30% by the year 2030, as compared to the 2005 baseline 6. The onus on new buildings is substantially higher to balance poor legacy stock. This is a challenging target and methodologies to cost effectively contribute to the achievement of this are to be derived by considering firstly building level and then district level interventions. 2. DESIGNING TO THE LIMIT Understanding how far to practically push a design requires a thorough technical and cost assessment. Through this exercise the designer then has the ability to consider the following quantified features How much energy, carbon, water or materials reductions will a certain initiative deliver; How much will this cost and what is the payback / return on investment; How does this compare to other alternatives; How much do I need to spend to achieve a certain goal. Figure 2 presents a flow diagram which highlights the design process required to enable a detailed energy / cost assessment. It should be noted that in order to make this process worthwhile the concept design stage needs to be more detailed than is typical; involving close collaboration with all professionals including the project quantity surveyor. 6 Hong Kong Green Building Council 2012 HK3030 A Vision for A Low Carbon Sustainable Built Environment in Hong Kong by

292 Concept + Design Advanced energy modelling Engineer/Architect Quantity Surveyor Refined options Capital/life cycle costs Engineer/Architect Quantity Surveyor Generate requirements to reduce uncertainty Figure 2: Closed Loop Design Process This process is highlighted by considering energy aspects of two projects in Hong Kong, both currently under design. Key project details are highlighted in table 1. For the projects detailed, the terms energy and electricity consumption are taken to be interchangeable as minimal natural gas is utilised, therefore total energy is equal to electrical consumption. Table 1: Project A and B Comparison Project A Public accessible building & associated support spaces Medium dense urban environment Developer, owner, occupier with tenant retail space Project B Grade A Office Dense urban environment Developer, owner, occupier with majority tenant lettable space To enable comparative analysis of different technologies energy / cost abatement curves are plotted for each project (figure 3 & 4). The vertical axis of the graph shows cost per unit of energy saved (HK$ / kilowatthour), i.e. the lower the value the more cost effective the measure. The horizontal axis shows % energy saving, i.e. the wider the bar the bigger the range. By plotting the data in ascending order of cost effectiveness the client / designers can then choose the systems with the least costs to achieve a desired energy consumption reduction. Two lines have been indicated on the chart, the first being the typical energy saving percentage (>20%) for a number of assessed BEAM Plus Gold/Platinum projects. The second being an upper level where advanced systems with little market validation or systems which require alterations to construction processes. Towards the right hand side of the graph are a number of systems that are relatively costly and the relevant energy savings small. As these systems are newer to the market they are expected to decrease rapidly in cost, around 5-10% per year is anticipated whilst efficiencies will also increase 7 meaning that in future the energy / cost abatement graphs will be constantly evolving. 7 Nagy B, Farmer JD, Bui QM, Trancik JE (2013) Statistical Basis for Predicting Technological Progress. PLoS ONE 8(2): e doi: /journal.pone

293 Basic Efficient lighting design Variable flow pumping Chiller control optimization Pressure control optimization Electronic Filters Office FCU Horizontal movement Efficient lighting layout and directional control Condensate heat recovery Vertical movement EC fans DC FCU Set point raise due to air movement Water cooled chillers with direct sea water cooling Heat recovery Air economizing (exhaust air dump) Occupancy Sensors Single oil-free chiller plant to cater for part load steps Solar desiccant dehumidification PAU Daylight Design Task lighting Cost HK$/kWhr saved Solar desiccant dehumidification AHU Direct Seawater cooled chillers including large ground works Distribution fan optimization Photovoltaic's - Option A - Thin Film Free-cooling (PAHU & AHU bypass 100% Oil-free chiller plant Common BEAM Plus Gold/Platinum Performance Advanced systems or construction implication Sustainable Building 2013 Hong Kong Regional Conference Figure 3 shows the energy / cost abatement plotted against capital expenditure for Project A in Hong Kong. 250 Solar heat protection Radiant cooling Earth Cooling 200 Preferable Higher potential energy saving for a single system 150 Preferable - Lower cost per energy saving % 5% 10% 15% 20% 25% 30% 35% 40% Arup 2013 % Energy Saving Figure 3: Energy / Cost Abatement For Project A Figure 4 shows the energy / cost abatement plotted against capital expenditure for Project B. Whilst both buildings are substantially different they have one key similarity achieving large energy and associated reductions in carbon emissions becomes very costly when energy savings are around 30%. It is worth noting at this juncture that costs relating to certain technologies can vary significantly from project to project. As such this is a bespoke exercise that must be carried for each project. It should also be noted that the energy / cost abatement figures here are assessed against the Electrical and Mechanical Services Department s (EMSD) Building Energy Code (BEC) In different climates the savings will be substantially different due to differing climate, conditioning and regulatory requirements. 8 EMSD 2012 Code of Practice for Energy Efficiency of Building Service Installation

294 Direct Seawater cooled chillers AC plug fan Active Silencer Ductwork air velocity enhancement Selection of Filters - High efficiency bag filter Higher Δt chilled water loop Air side static pressure reset Air side economizer Optimized lighting illuminance Lighting type - 13W T5 VAV Beam (perimeter) + Passive Chilled beam (interior) Demand control ventilation Heat wheel Solar cooling Wind Turbines Selection of Filters - Electronic filter Natural curve control Low Friction Oil-free chillers Cost HK$/kWhr saved Cooling coil rows type Bio-diesel tri-generation (with absorption chiller) Daylight control Dry type Fan Coil Unit + DDhum PV fins Raised Floor Plenum Pressurized Type (Supply and return louver on floor) Common BEAM Plus Gold/Platinum Performance Advanced systems or construction implication Selection of Filters - Electric filter EC plug fan Occupancy control AHU Sub-zoning Lighting type - LED Sustainable Building 2013 Hong Kong Regional Conference Preferable Higher potential energy saving for a single system Preferable - Lower cost per energy saving Heat pipevsd cooling tower Free cooling PV roof Variable Speed Drive Chiller 0 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% Arup 2013 % Energy Saving Figure 4: Energy / Cost Abatement For Project B 3. LOOK BEYOND THE BUILDING As noted above, when buildings reach a figure of around 30% energy saving over the BEC it becomes more cost effective to look towards district level systems which offer increased energy savings and the added benefit of spreading capital expenditure across multiple developments. The following section highlights three areas where looking beyond the building can add significant cost-effective energy reduction in particular DISTRICT SEA WATER HEAT REJECTION The application of direct sea water cooled chillers has significant energy benefits for project A at 1.7% reduction in building energy consumption. Whilst other Hong Kong projects have shown energy reductions in the order of 3-4%. This energy reduction is due to the reduced chiller lift required due to the lower condenser water temperatures during the peak cooling season. The capital expenditure uplift compared to conventional chillers was however significant for project A at 61 HK$/kWhr, placing it as one of the most expensive technologies. The cost uplift is largely driven by the extent of ground works to connect the chiller plant to the sea, with Project A baring sole responsibility for the costs. This case highlights that the uptake of district networks can share ground work costs among multiple buildings and increase financial viability. This is essential for the large scale uptake of district systems. 6

295 It should be noted however that this paper does not consider the commercial nature of contracts for connection to district systems and the possible increased operation expenditure associated with purchased cooling 3.2. BIOFUELS FROM WASTE COOKING OIL One element of waste with potential in Hong Kong are biofuels from waste cooking oil generated from restaurants. Through relatively simple processes this oil can be turned into bio diesel and used to power tri-generation combined cooling heat and power (also commonly known as CCHP). This offsets the carbon emissions associated with the use of grid electricity and has the added benefit of reducing the need to treat cooking oil as a waste stream. Based on our studies a biofuel volume of around 0.04 to 0.06 tonnes/m 2 /annum (based on an energy usage intensity (EUI) of kwhr/m 2 ) is required to produce cooling, heating and power through tri-generation. Assuming a typical 20 story building of total area 60,000m 2 at an EUI of 100 kwhr/m 2 would require around 2,400 tonnes / year of biofuel to feed a tri-generation plant. Proposed production plants (under construction) 9 are proposed to handle 100,000 tonnes / year RENEWABLE TECHNOLOGIES One could argue that adding more renewable technology to building lowers the energy demand. However, the calculation below demonstrates that, in the dense urban context, building space to locate technology becomes very limited. For a typical 20 storey high rise the roof space will struggle to locate enough photovoltaic (PV) panels that could significantly reduce building emissions. Consider a 20 story building 60,000m2 at an EUI of 100kWhrs/m2/yr, it will consume 6,000 MWhrs/yr. Assume PV panels generate 120kWhrs/ m2/yr and 50% of the roof area is used then only around 3% of building energy can be generated. The assumptions for energy generation, PV space utilization and low building EUI are highly optimistic and it is expected that in practice substantially less energy would be generated. The costing for Projects A & B showed that PV is a relatively expensive product varying between 63 and 123 HK$/kWhr. However, there may well be economies of scale available for larger energy farms, indeed, this costing exercise showed that for Hong Kong s climate, thin film amorphous PV costs are over 30% more cost effective (HK$/kWhr) compared to polycrystalline panels, but require almost twice the area. Locating such technology away from dense urban centres relieves to some extent space pressure in Hong Kong. 9 Based on proposed ASB Biofuels manufacturing site 7

296 Cost HK$/kWhr saved Sustainable Building 2013 Hong Kong Regional Conference 3.4. SUMMARY Figure 5 shows that at around 30% energy saving, costs for systems grow rapidly and potential energy reductions reduce. It can be argued that this is the point at which district systems and district integration should be employed to reduce emissions further and indeed to achieve stretched performance targets cost-effectively this is the sensible choice. 250 Project A Project B Low Hanging Fruit Zone Cost Premium Zone Low and Zero Carbon Technology Investment Zone Or District Investment User behavior change and technology efficiency improvements* Likely performance requirements for new buildings with greater opportunities for improvements Cost of photovoltaic panels 0 0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0% % Energy Saving *User behavior change and technology efficiency improvements are assumed to enable a 25% improvement in small usage Carbon Zero Buildings Figure 5: Energy / Cost Abatement Summary 4. CONCLUSION It is apparent that the energy consumption of buildings in Hong Kong has to be reduced considerably in order to play our part in the global attempt to reduce carbon emissions and limit climate change. The key findings from this study are; Current designs and technologies mean building level energy reduction is difficult and costly beyond ~30% New build electricity consumption savings of significantly over 30% required to meet HK30/30 targets District wide systems such as direct sea water district cooling, waste to energy and district scale renewable technology should be investigated to provide further energy reduction Whilst this paper has considered the demand side reductions, it should also be noted that supply side reform through grid decarbonisation shall have a role to play in addressing the overall reduction of Hong Kong carbon emissions. 8

297 There is no single technology or method available to reduce carbon emissions to the levels required, therefore a range of measures are essential to solve the energy and carbon emissions crisis. 5. REFERENCES Council for Sustainable Development, 2011, Invitation for Response Document 2011: Combating Climate Change: Energy Saving and Carbon Emission Reduction in Buildings. Hong Kong Green Building Council 2012 HK3030 A Vision for A Low Carbon Sustainable Built Environment in Hong Kong by Baer, P. and M. Mastrandrea, 2006, "High Stakes: Designing emissions pathways to reduce the risk of dangerous climate change", Institute for Public Policy Research, Nagy B, Farmer JD, Bui QM, Trancik JE (2013) Statistical Basis for Predicting Technological Progress. PLoS ONE 8(2): e doi: /journal.pone Hong Kong Green Building Council, HK3030 A Vision for A Low Carbon Sustainable Built Environment in Hong Kong by Hong Kong EMSD, Code of Practice for Energy Efficiency of Building Service Installation Hong Kong 9

298 A NEW DIMENSION FOR ENVIRONMENTAL FRIENDLY TEMPORARY OFFICE ENERGIZING KOWLOON EAST OFFICE Alan SIN 1 Architectural Services Department, HKSAR Government, HKSAR Vincent CHENG Building Sustainability Group, Arup And Jimmy YAM Building Sustainability Group, Arup 1 sinkla@archsd.gov.hk, Tel: (852) , Fax: (852)

299 A NEW DIMENSION FOR ENVIRONMENTAL FRIENDLY TEMPORARY OFFICE ENERGIZING KOWLOON EAST OFFICE ABSTRACT In late 2011, the Development Bureau of HKSAR looked for a temporary office accommodation for the Energizing Kowloon East Office (EKEO), set up to steer the transformation of Kowloon East. Upholding the Government s clear direction for sustainable development especially for this new development area, it is important to stem a clear image of green building for EKEO. A piece of unattractive land underneath the Kwun Tong Bypass was identified which is ideally located at the heart of the Kowloon East area. After spending just 6 months from design to construction, a two-storey building that can accommodate 20 staff and 50 visitors within its 1,200 m 2 floor area was expeditiously built in May Apart from the required office facilities, there are an Information Kiosk with briefing hall, exhibition area, 2 conference rooms, washrooms and a central courtyard. Modular construction by using recycled freight containers and mild steel framing structures fixed by bolts and nuts for flexibility in layout changes was adopted. These materials can also be easily dismantled and reused elsewhere at the end of the building s life. Low embodied energy and sustainable materials were also used. Passive designs help reduce EKEO s energy footprint while creating a pleasant and comfortable environment. Simple idea like using the Kwun Tong Bypass to shade the building significantly reduces solar heat gain. Perforated external walls with cross-ventilated windows facilitate cool breeze to flow through the whole office space. Other energy efficient installations like variable refrigerant volume (VRV) air conditioners and T5 fluorescent tubes with daylight and motion sensors save significant energy consumption. Low-flow taps and harvesting rainwater for irrigation greatly reduce water consumption. As a result of the above, EKEO was certified as the first Platinum (Provisional) rated BEAM Plus temporary building in Hong Kong, attracting over hundreds of visits from all over the world. Keywords: Low Carbon; Low Embodied Energy; Environmental Friendly Construction; Passive Designs; Water Saving. 1. INTRODUCTION Hong Kong is globally renowned for its high-rise, high-density urban context. The challenge is how to create a compact livable built environment for the population of over 7 million in a territory of merely 1,000 square kilometers CHALLENGES ON SUSTAINABLE BUILT ENVIRONMENT CARBON FOOTPRINT According to the latest figure issued by the Environmental Protection Department (EPD) of the HKSAR Government, the carbon footprint of Hong Kong is 6.1 tonnes per capita, which is about double that of the global average. Electricity generation accounted for around two thirds of the total emissions, among which 90% related to buildings (Environment Bureau, 2010). In other words, electricity consumed by buildings contributes to about 60% of Hong Kong s carbon emission. This implies that reducing building electricity consumption plays a key role in minimizing Hong Kong s carbon footprint. Other major contributing sectors include transportation and waste. 2

300 RESOURCES AND WASTE MANAGEMENT Other than energy consumed by buildings, waste minimization and resources conservation, such as material and water, are also key issues for sustainable development of Hong Kong. For instance, it is identified that annual solid waste disposed at landfill is close to 13,500 tonnes per day in 2011 (EPD 2012). Currently, the waste treatment in Hong Kong is mainly relying on disposing the waste to landfills, and the existing landfills would be filled up by 2015 if the trend continues (EPD, 2005). Solid waste management becomes one of the local priority issues. In addition, material conservation and water management are also important to maintain a quality living environment while minimizing environmental impacts GOVERNMENT POLICIES AND INITIATIVE FOR SUSTAINABLE DEVELOPMENT To foster the development of a low carbon sustainable built environment, the HKSAR Government has established a series of policies and initiatives. Some of them are highlighted below TECHNICAL CIRCULARS To take the lead in driving green buildings in Hong Kong, the HKSAR Government has published a set of technical circulars (TCs) requiring all new government buildings to adopt environmentally friendly measures where practicable, such as: (i) Development Bureau TC No. 5/2009. Green Government Buildings - It stipulates that all new government buildings with construction floor area (CFA) of more than 10,000m 2 should aim to obtain the second highest grade of above under an internationally or locally recognised building environmental assessment system, such as BEAM Plus. (ii) Development Bureau TC (Works) No. 2/2011. Encouraging the Use of Recycled and other Green Materials in Public Works Projects - It sets out a comprehensive framework for a procurement of recycled and other green materials with a view to promoting their use in public works projects. (iii) Environment, Transport and Works Bureau TC (Works) No. 16/2005. Adoption of Energy Efficient Features and Renewable Energy Technologies in Government Projects and Installations - It sets out the guidelines and procedures on the adoption of energy efficient features and renewable energy technologies in government projects and installations SUSTAINABLE BUILDING DESIGN GUIDELINES (SBD GUIDELINES) The SBD Guidelines were developed from a consultancy study named Building Design that Supports Sustainable Urban Living Space in Hong Kong commissioned by the Buildings Department (BD) to promote building separation, building set back and site coverage of greenery (BD, 2011). The compliance with the SBD Guidelines would be taken into account as a pre-requisite in exempting or disregarding green/amenity features and non-mandatory/non-residential plant rooms and services from gross floor area (GFA) and/or site coverage calculation (GFA concessions) in new building developments. 3

301 BUILDING ENERGY EFFICIENCY ORDINANCE (BEEO) To promote building energy efficiency, the HKSAR Government enacted the BEEO in September 2012 which mandates the following 3 key requirements: (i) The 4 key types of building services installation of newly constructed buildings, namely air-conditioning, lighting, electrical as well as lift and escalator installations, should comply with the Building Energy Code (BEC) issued by the Electrical and Mechanical Services Department (EMSD, 2012a). (ii) The responsible persons (i.e. owners, tenants or occupiers etc.) in buildings should ensure that the 4 key types of building services installation comply with the design standards of the BEC when major retrofitting works are carried out. (iii) The owners of commercial buildings (including the commercial portions of composite buildings, e.g. shopping malls under residential storeys) should carry out energy audit for the 4 key types of central building services installation in accordance with the Energy Audit Code (EAC) (EMSD, 2012b) every 10 years MANDATORY ENERGY EFFICIENCY LABELLING SCHEME (MEELS) To facilitate the public in choosing energy efficient appliances and raise public awareness on energy saving, the Government has introduced the Mandatory Energy Efficiency Labelling Scheme (MEELS) through the Energy Efficiency (Labelling of Products) Ordinance. Under MEELS, energy labels are required to be shown on the prescribed products for supply in Hong Kong to inform consumers of their energy efficiency performance. MEELS currently covers five types of prescribed products, namely room air conditioners, refrigerating appliances, compact fluorescent lamps (CFLs), washing machines and dehumidifiers ENVIRONMENTAL FRIENDLY MATERIALS & EQUIPMENT For government buildings, the use of environmental friendly materials such as certified timber from sustainable forest, low VOC paints have been incorporated into the General Specification for Building. Environmental friendly building services equipment & installations are also specified in a series of General Specifications for Building Services Installation in Government Buildings WATER EFFICIENCY LABELLING SCHEME (WELS) The Voluntary Water Efficiency Labelling Scheme (WELS) is a water conservation initiative of the HKSAR Government. Products participating in WELS will incorporate a water efficiency label that will tell consumers the level of water consumption and water efficiency to help consumers choose water efficient products for water conservation. The WELS covers different groups of plumbing fixtures and appliances including water taps, shower heads, washing machines and urinal equipment. 2. THE ENERGIZING KOWLOON EAST OFFICE (EKEO) The EKEO (Figure 1) is established under the Development Bureau to oversee a new policy initiative called Energizing Kowloon East announced by the Chief Executive in the Policy Address to facilitate the transformation of Kowloon East into an 4

302 attractive alternative Central Business District and to support Hong Kong s long term economic development. The new initiative covers the business areas in Kwun Tong and Kowloon Bay and also the strategic planning of Kai Tak Development (KTD). The temporary office accommodation for the EKEO is located at Hoi Bun Road underneath the Kwun Tong Bypass with close proximity to both the KTD and the target industrial areas within Kowloon East. Apart from the exhibition of project related information, the office also serves as a venue for holding public engagement events and providing educational resources for promotion of green building technology. Figure 1: The Energizing Kowloon East Office (EKEO) 3. SUSTAINABLE DESIGN APPROACH To foster the notion of low carbon footprint through practical and innovative sustainable measures, specialist consultants were engaged to formulate a sustainable design solution for the EKEO building. A series of integrated building innovations and sustainable building design strategies have been adopted as detailed below MODULAR CONSTRUCTION To reduce embodied energy, construction waste and associated environmental impacts, modular construction approach was adopted. This includes the use of recycled freight containers and mild steel framing structures fixed by bolts and nuts. As a result, the use of prefabricated building components as well as flexibility in layout changes are maximised. The building materials can also be easily dismantled and reused elsewhere at the end of the building s life. Figure 2: Modular Construction using Standardised Freight Containers and Steel Members 3.2. USE OF ENVIRONMENTAL FRIENDLY CONSTRUCTION MATERIALS Low embodied energy and sustainable materials were also adopted in the construction of the EKEO building. The use of second-hand freight containers as the main building structure minimised the energy consumed and environmental impacts during the extraction of virgin materials and manufacturing process. From the Life Cycle Assessment (LCA) using the EMSD LCA Tool, the estimated amount of embodied 5

303 energy saved is equivalent to 2.3TJ. Similarly, the embodied energy and environmental impact due to transportation of construction materials were also reduced by using nearly 100% of regionally manufactured building materials (within 800 km of the project site). In addition, the paving blocks for the site were manufactured from recycled materials (recycled aggregates, recycled glass and fly ash), coated with titanium dioxide (TiO 2 ), which helps abate nitrogen oxide (NO x ) from road vehicles. This purifies the ambient air and benefits the health of the building users and pedestrian. Besides, the wood cabinets in the office were made of certified timber from sustainable forest PASSIVE DESIGNS One of the key strategies for minimising energy footprint is to reduce the building energy demand. In this connection, various passive design measures are utilised. For instance, the building disposition was carefully planned such that around 80% of the roof areas are covered by the Kwun Town Bypass to minimise solar heat gain. Other than that, perforated external walls in form of bamboo fence were installed to capture cool breeze to the courtyard area. Moreover, windows were installed on opposite sides of the office areas and Information Kiosk to facilitate cross ventilation. (a) Perforated wall at Central Courtyard (b) Airflow simulation at the Information Kiosk (c) Opposite windows for cross ventilation Figure 3: Perforated External Walls and Opposite Windows to Facilitate Natural Ventilation To enhance daylighting, the underside of the Bypass, painted white, is used as a lightshelf to reflect daylight, making the central courtyard well-lit throughout the day without artificial lighting. The shallow depth of the office space (less than 5m) and the opposite windows also facilitate daylight penetration (a) Central Courtyard (b) Entrance Foyer (c) Office Figure 4: Daylighting to Reduce Lighting Energy Consumption 3.4. ENERGY EFFICIENT SYSTEMS Another energy reduction measure is the use of energy efficient systems. Variable refrigerant volume (VRV) air conditioners were installed which energy efficiencies (above 3.8) are much higher than room air conditioners / split units (usually below 3.0). For lighting, T5 fluorescent tubes integrated with task lights effectively reduce the 6

304 lighting power density (LPD). Besides, daylight and motion sensors were installed to further save lighting energy consumption if the lighting is not required TOTAL WATER MANAGEMENT To minimise fresh water demand, low-flow taps were installed at the toilets and pantry. In addition, rainwater is also harvested for irrigation of the landscape areas. Consequently, the carbon emissions due to fresh water processing are reduced QUALITY INDOOR ENVIRONMENT Good indoor air quality (IAQ) contributes to the health of the occupants and productivity of the staff of EKEO. To improve IAQ, the ventilation system was designed to provide higher outdoor air ventilation rates than the minimum requirements by ASHRAE (ASHRAE, 2007) to facilitate dilution of indoor air pollutants. Meanwhile, independent exhausts are also provided for photocopiers to remove the particulates at source. An IAQ measurement was conducted and the result illustrated that the indoor air quality meets the Good Class of the IAQ Certification Scheme (HKSAR Government, 2003). Moreover, the building is set back from the street boundary by about 16m to minimise traffic noise impact from the abutting road WASTE MINIMIZATION The extensive use of prefabricated building components such as the freight containers and mild steel framing structures help minimise construction waste. Furthermore, most of the construction waste including wood, rebar and concrete were reused or recycled SITE SPECIFIC DESIGN FOR LAND SAVING To save precious land for other use, the EKEO was set up by revitalising a piece of unattractive land on a site under the Kwun Tong Bypass. With the above evidences of sustainability performance, the EKEO building has shown the innovative way to convert site constraints into opportunities for building sustainability EFFICIENT CONSTRUCTION MANAGEMENT To meet the tight construction programme and reduce nuisance to the surroundings, several measures were undertaken to enhance construction management, such as offsite fabrication and reduction of inter-phasing. (a) Off-site Fabrication Yard (b) Minimise Inter-phasing of Building Structure & Building Services Works Figure 5: Efficient Construction Management KEY PERFORMANCE INDICATORS AND ACHIEVEMENTS The EKEO building achieved outstanding performances in various environmental aspects. Table 1 summarises the key performance indicators (KPI). The building was 7

305 also certified as the first Platinum (Provisional) rated BEAM Plus temporary building in Hong Kong, attracting over hundreds of visits from all over the world, including the Mayor of Barcelona within half a year of his inauguration in June Table 1: Key Performance Indicators (KPI) of the EKEO Aspects Sustainable Measures Estimated Savings / Reduction Energy Passive designs ~35% Use of energy efficient systems Water Use of water efficient fixtures ~61% Rainwater harvesting Materials Use of environmental friendly materials Regional materials Recycled materials Certified timber Nearly 100% of building materials were manufactured regionally 46% of building structure and 30% of outdoor works were made from recycled materials Certified timber for 80% of wood products Waste IAQ Waste minimization through Modular construction Recycling construction waste Increased ventilation Independent exhausts for photocopiers Modular design for 90% of building structure Recycled 80% of construction waste Good Class of IAQ Objectives 4. CONCLUSION As the first low carbon temporary office, the EKEO has made a new move towards sustainable development in Hong Kong s construction industry. It demonstrates how to apply this new concept for future temporary buildings, such as site offices. 5. ACKNOWLEDGEMENT The success of the EKEO is a result of the remarkable efforts from the project team including Development Bureau, Architectural Services Department, Civil Engineering and Development Department, Arup, and Shui On Building Contractors Limited. 6. REFERENCES ASHRAE, ASHRAE Standard : Ventilation for Acceptable Indoor Air Quality Buildings Department, Practice Note for Authorized Persons, Registered Structural Engineers and Registered Geotechnical Engineers APP-152: Sustainable Building Design Guidelines. Electrical and Mechanical Services Department, 2012a. Code of Practice for Energy Efficiency of Building Services Installation. Electrical and Mechanical Services Department, 2012b. Code of Practice for Building Energy Audit. Environment Bureau, Hong Kong s Climate Change Strategy and Action Agenda. Environmental Protection Department, Municipal Solid Waste ( ). A Policy Framework for the Management of 8

306 Environmental Protection Department, Monitoring of Solid Waste in Hong Kong HKSAR Government, A Guide on Indoor Air Quality Certification Scheme for Offices and Public Places. 9

307 SKY GARDEN DESIGN IN HIGH-DENSITY HIGH-RISE RESIDENTIAL DEVELOPMENT Tony Ip 1 B.Eng., B.BltEnv.(Dist.), M.Sc., M.Arch.(Dist.), M.UrbanDesign(Dist.), M.St.IDBE RA(HK), AP(Architect), HKIA, HKIUD, BEAM Pro Ronald Lu & Partners (Hong Kong) Ltd., Hong Kong 1 Tony Ip - Address: Ronald Lu & Partners (Hong Kong) Ltd., 33/F., Wu Chung House, 213 Queen s Road East, Wanchai, Hong Kong, tonyip@rlphk.com / tony_7699@yahoo.com, Tel: (852) , Fax: (852)

308 SKY GARDEN DESIGN IN HIGH-DENSITY HIGH-RISE RESIDENTIAL DEVELOPMENT ABSTRACT The Hong Kong government issued green incentives for sky gardens in domestic buildings in 2001, including gross floor area exemptions and relaxation of the allowable overall building height in regard to provision of sky gardens. Such incentives were conceived to encourage developers to incorporate greening measures in new residential high-rise buildings; however, these incentives have been criticized due to uncertainty of whether these sky gardens provide benign effects to the local micro-environment. Further criticism has been directed against whether the sky gardens are underused due to windy conditions, poor connectivity or access, and lack of recreational facilities to suit their intended purpose. Case studies of twenty sky gardens in high-rise residential developments inform that the location and openness of sky gardens are not optimized to alleviate air flow at the street level and improve microclimate in the existing urban contexts. A survey on residents experiences in sky gardens is conducted in three residential developments with distinctive characters of sky gardens in terms of sky garden locations and connectivity, amenity provisions, design themes, surrounding urban contexts, and property completion years. One-third of the residents never visit their sky gardens and no daily visitors are found, whilst the elderly and children are infrequent users of sky gardens. It reveals that misunderstanding of the values of sky gardens and personal perceptions may cause the low occupancy rate but more positive experiences are reported as a result after residents visit the sky gardens. Residents habits and living patterns affect decisions on whether to utilize outdoor communal spaces and spend time for enjoyment in sky gardens. The study evaluates the effectiveness of existing sky gardens and discusses design of effective sky gardens for improving environmental quality and social interaction in densely occupied, high-rise contexts. Keywords: High-rise; Residents Experience; Sky Garden; Urban Living. 1. BACKGROUND Sky gardens have been promoted by the Hong Kong government since 2001 as a design strategy to improve the quality of the living environment by balancing social, environmental, and economic concerns. A decade later, the benefits and functions of sky gardens are not obvious, leading to only a limited number of new residential buildings in Hong Kong being provisioned with sky gardens. In the high-density urban environment, the scarcity of land squeezes development of high-rise greenery away from the ground level. In Hong Kong, there are three types of gardens in high-rises: podium gardens, sky gardens, and roof gardens. Sky gardens are scattered at various levels of a tower, while podium gardens and roof gardens are situated on the roof of a podium and a tower respectively. This paper investigates the characteristics of existing sky gardens, analyses their environmental, social and economic performances, evaluates residents experiences, and discusses design of effective sky gardens in high-density, high-rise residential developments. It focuses on sky gardens at storeys of densely-populated residential high-rises in urban areas. 2

309 2. GARDENS IN URBAN LIVING Sense of community is only evoked with profound opportunities of social interaction. The demand for a peaceful and natural environment in the urban areas has increased; people desire such environments where they can stay, chat, and otherwise interact with their family, friends, neighbours, and passers-by (Connell, 2004; Kaplan and Matsuoka, 2008). Green spaces have direct and indirect benefits on environmental, social, and economic aspects in urban living (Givoni, 1991; Goddard et al., 2009; HKSAR, 2009). Can sky gardens be an option of bridging nature with urban living? Residents of high-rises have a strong desire for pleasant communal green spaces that can encourage social interaction and communal activities amongst neighbours in proper circumstances (Chien and Wang, 1999; Huang, 2006). For urban dwellers, the opportunity to breathe clean air and exercise is their main driver to visit green spaces; and they are willing to pay more for residences with more green spaces (Chen and Jim, 2010; Jim and Lo, 2010). Unfortunately, a survey in Singapore showed that green spaces in high-rises, such as roof gardens, were under-utilized due to a lack of people s awareness of such green spaces (Wong and Yuen, 2005). Green spaces are essential in a child s healthy development. Children in the city may develop nature-deficiency disorders with physical inactivity, thus eliciting social and psychological ramifications and an increase in the trend of chronic diseases. Green environments and pleasant outdoor spaces can encourage children to be more active and improve their health (Lee and Min, 2006; Kuo et al., 2002; McCurdy et al., 2010). Meanwhile, elderly residents prefer garden apartments and have a greater sense of community there. Green common spaces benefit the social integration of older adults in the inner-city, which can also indirectly lessen public expenditure on individual elderly services (Delvin and Zaff,1998; Kweon et al., 1998). 3. SKY GARDENS Sky garden is a form of micro-environmental design meant for improving wind conditions in urban districts and providing a recreational garden space. Research findings on the topic of sky gardens are limited. However, available research regarding sky gardens in Hong Kong (Niu, 2004) states that sky gardens provide better thermal comfort in the summer. There is only one set of available guidelines for the design of sky gardens in Hong Kong (HKSAR, 2001). Some key points extracted are listed as follows:- i. Locations of sky gardens are recommended to be determined by wind tunnel testing or computation fluid dynamic modelling but it is not compulsory. ii. The maximum number of sky gardens provided is equal to or less than the number of residential storeys divided by 15. Such a garden can be split into multi-levels but it occupies not less than one-third of the area of the floor plate. iii. The first sky garden is located at not more than 10 storeys where more than iv. one sky garden is provided and where there is no podium garden. The minimum headroom is 4.5m and it is open-sided above safe parapet height on at least two opposite sides for cross ventilation. v. Sky gardens can be coupled with refuge floor. vi. Not less than 25% of the area of the floor plate is to be vegetated. 3

310 4. CHARACTERISTICS OF SKY GARDENS IN HIGH-RISE RESIDENTIAL DEVELOPMENTS IN HONG KONG According to the government statistics in (HKSAR, 2008), only 14 residential buildings completed within that time were provisioned with sky gardens, equalling only 3% of the 520 new buildings completed in that period. Case studies of twenty sky gardens in high-rise residential buildings were carried out. These buildings were built after the Hong Kong government s implementation of the green incentives of sky gardens in Some common characteristics of sky gardens in Hong Kong are identified as follows:- i. With the effects of green incentives, height concession is the main driver for the provision of sky gardens such that units above sky gardens can be elevated with better distant views, resulting in higher property prices. ii. Most of the sky gardens at mid-levels are mainly designed for the purpose of refuge floors. For those at low- and high-levels, sky gardens are usually adjoined to podiums or sky clubhouses that act as an extension of the clubhouses area or serve as main circulations to the clubhouses from individual tower blocks. iii. The total opening of sky gardens in proportion to the overall building height is merely 2-3%. Two-thirds of the gardens are located at mid- and high-levels about m from the street that impose insignificant effects on improving air flow at the pedestrian street-level and microclimate in the old urban context of high-density built environments at 60m or below. In considering most of the sky gardens located at 60m or below, the ratio of openness to its level from the street is about 5%, which is not comparable to 22% of one case that 14.5m high sky garden is purposely designed for alleviating air ventilation. iv % of the net floor areas are vegetated in sky garden. About 45% of outdoor areas serve as circulation and event spaces. Structural configuration and fire service installations restrained the spatial planning in sky gardens. Amenities mainly facilitated passive activities such as leisurely sitting areas, viewing platforms, strolling paths and foot massage trails. 5. RESIDENTS EXPERIENCES IN SKY GARDENS To investigate the values of sky gardens from the residents perspectives, a survey was conducted in three residential developments with distinctive typology of sky gardens as shown in Table 1. The questionnaires were completed through face-to-face interviews with individuals and the number of successful respondents was ninety in total (thirty per development typology). Table 1 Sky gardens selected for the survey on residents experiences. Typology One mid-level sky garden One low-level and one mid-level sky garden Location Sai Wan Ho, HK (Harbour Front) Quarry Bay, HK (Urban Area) Completion Property 5 blocks, storeys, 2 blocks, 38 storeys, Description 2020 units 442 units One high-level sky garden connecting to a sky clubhouse Cheung Sha Wan, HK (An Old District) 2 blocks, 37 storeys, 400 units Occupancy Rate & Pattern 33.3% of residents never visit their sky gardens, 40% visit during festivals or special occasions, and 26.7% visit regularly on a weekly or monthly basis, but none on a daily basis. Residents between the age of are both the main group of respondents and sky-garden users simultaneously. The elderly and children are not the most 4

311 frequent users although they spend the longest time in residential buildings on weekdays. Residents, who live in sq.ft & sq.ft flats, visit sky gardens more frequently and on a more regular basis. Daytime visitors are not the majority. 42.6% of residents visit sky gardens after 8pm, 34.9% between 3-8pm and 13.4% between noon-3pm. Different typologies pose slight variations of residents experiences and their occupancy patterns. Reasons for Visiting Sky Gardens The most agreed reason why residents visit sky-gardens is landscaped garden with scenic views. The second reason is self-retreat / reading in a peaceful environment. The third is leisure walk with family & friends, and the least is children play / doing exercise & stretching. The reason of communal space for chatting with neighbours is disregarded. Compared with those visiting sky gardens occasionally, residents who visit on a regular basis have a higher degree of satisfaction for leisure walk with family & friends and self-retreat / reading in a peaceful environment. Reasons for Not or Seldom Visiting Sky Gardens For residents who never visit sky gardens, they consider lack of amenity facilities as the main reason. Other reasons for not visiting sky gardens, including too windy, difficult to access, safety concerns and insecure sense, are quite distinctive amongst the three developments. More positive comments on sky gardens, except for too windy, are received from residents after they have visited there. Values of Sky Gardens Most of the residents agree that the values of sky gardens is to provide more outdoor communal spaces, provide more green spaces, and enhance property value. More seating and recreational facilities, especially for children playing, should be provided. In summary, residents misunderstanding of the values of sky gardens and personal perceptions may cause low occupancy rate, but more positive experiences resulted after residents visited the sky gardens. Residents habits and living patterns affect decisions on whether to utilize outdoor communal spaces and spend time to have enjoyment in sky gardens. Social interactions amongst neighbours are relatively difficult to achieve, but sky gardens have a definite positive impact to urban living for individuals and families in Hong Kong. 6. DISCUSSION ON EFFECTIVENESS OF SKY GARDENS IN HIGH- DENSITY HIGH-RISE RESIDENTIAL DEVELOPMENT Can the existing sky gardens improve the quality of urban living? Only few developments with sky gardens and low occupancy rates have been observed. It may relate that either developers or residents do not understand or fully experience the merits of sky gardens. On the other hand, the government policy has not effectively encouraged good quality of sky garden design in optimizing its environmental, social, and economic performances. Environmental Performance With sky gardens, the building permeability and greenery ratio increase, but the magnitude is not obvious. The ratio of clear openings at sky gardens to the overall building height is merely 2-3%. Two-thirds of sky gardens are located in the mid- and high-levels of buildings, about m from the street. These sky gardens impose an insignificant effect on improving air flow at the pedestrian street-level or in the existing urban context where old buildings are at 60m or below. Furthermore, the actual 5

312 vegetated areas within sky gardens are fragmented and occupy less than a quarter of the net floor area. The effectiveness of alleviating the wall effect and urban heat island effect is in question. Social Performance Residents generally agree that their sky gardens offer scenic and peaceful environments for self-retreat, resting, reading, and leisurely walks with family and friends; thus more greenery and garden areas are strongly requested. Residents within the age of are the main sky garden users while the elderly and children do not visit frequently. It is arguable that sky gardens are ideal places for children to play and the elderly to exercise, subject to appropriate amenities and parapet designs that are sensible and safe. Nonetheless, a sky garden is not considered as a communal space to encourage more social interactions among neighbours. Economic Performance The height concession to elevate the overall building height incentivizes the provision of sky gardens in new developments from the developers perspective. On the other hand, residents consider that sky gardens can enhance their property value by providing more pleasant communal spaces and greenery. However, it is not comparable to other communal facilities such as clubhouses or podium gardens. Current Design Guidelines The current design guidelines of sky gardens have not been thoroughly implemented. For instance, locations of sky garden are recommended to be determined by a wind tunnel testing or computation fluid dynamic modelling; however, none of the studied projects determined their sky garden locations by following published recommendations except where specific statutory planning conditions were imposed. Negation of testing and modelling recommendations may be due to implications of substantial costs and/or time. Although multi-level sky gardens are allowed, it is not uncommon that residential highrises of more than 30 storeys have only one single-level sky garden to satisfy green incentive credits. In the twenty case studies, only one-fifth of developments incorporate two sky gardens and none of them have split-level sky gardens. Reasons to explain this phenomenon are that either there is a lack of successful sky garden implementation, or that the building authority prevents the abuse of height recession and likely requests more deliberate justification for environmental improvement if more than one sky garden is proposed. A question arises in regard to what would be more appropriate to specify prescriptive building permeability requirements for environmental improvement by a podium garden, a sky garden or a combination of them? How can the design of sky gardens maximize benefits for urban living in highdensity high-rise residential developments? If we consider that a sky garden is an alternative communal space for leisure activities and a relaxing outdoor green environment that promotes healthy and sustainable living quality, then provisioning of such an appealing covered landscaping area is a perquisite rather than a by-product in the design of new residential developments. Greenery has positive effects in urban living in particular to the aging population and for children s healthy development. Furthermore, residents express their strong preference to the living environment with more planting. The green ratio is suggested to be determined in relation to population or gross floor areas instead of the ratio of the site area, which is of the similar approach in determining sufficient recreational facilities. 6

313 Building Permeability and Greenery To improve building permeability and alleviate urban ventilation, the sky garden should be located at low levels and of higher floor height. References can be made to the case of 14.5m high sky garden and to design guidelines of 13m high sky gardens in Singapore. A 6m floor height with 4.5m clear headroom is advisable for sky gardens at high levels and even for a sky garden that serves the purpose of a refuge floor; otherwise, daylight is not sufficient at the inner part of the garden area. Similarly, if greenery can effectively alleviate urban micro-climatic conditions, the green cover area at the sky garden should be large enough to incur positive environmental results. Trees and shrubs of various species and heights should be planted in order to achieve a desirable environmental comfort and create an authentic-feeling garden. Amenity and Spatial Quality The popularity of new private residential buildings with sky clubhouses has justified that recreational facilities at high levels may not be residents concern in residential highrises; however, how attractive the destination may be is an issue. More greenery and diversity in amenity facilities are expected by residents. To promote a low carbon living environment, a sky garden can act as a naturally-ventilated sky clubhouse which provides amenity facilities to residents in a more energy efficient way. Furthermore, the usage of a designated space like a refuge floor that is converted into a sky garden is encouraged, but its spatial quality has to be improved, including wider and higher event spaces and appropriate planter areas for a variety of plant species. Design of Effective Sky Gardens Three types of sky gardens are proposed in view of specific environmental and social functions. First, sky gardens are designed with high headroom located at or below 60m to emphasize improving upon a building s permeability and environmental quality. Second, sky gardens with larger event spaces and attractive elderly friendly facilities and children s play amenities above 60m can facilitate more outdoor recreational spaces for residents and act as naturally-ventilated sky clubhouses. Third, pocket-sized sky gardens with extensive planting are integrated within communal circulation spaces, such as lift lobbies and corridors on residential floors, and are scattered in the building at multiple levels, which offer more chances of social interactions amongst neighbours and physical contact with greenery and facilitate impromptu extension of living spaces. 7. CONCLUSION The higher we live from the ground level, the more disconnected we feel from the natural world and even from each other within a community. We can understand that sky gardens may provide beneficial impacts on environmental and social aspects in urban living, and supplement deficiencies and needs in highdensity, high-rise residential developments. Benefits to the environment derived from the implementation of sky gardens include improved human thermal comfort and urban microclimate, increased social cohesion through the provision of a community green space, provisioning of a place for individuals to escape from the busy city life, improved community integration for all age groups, and improved health and well-being. In practice, improving environmental quality and enhancing social interactions are not considered important factors by residents of developments. The case studies show that the location and openness of sky gardens are not optimized to alleviate air flow at pedestrian level and microclimate in the existing urban context. Moreover, the fragmented configuration of planters in sky gardens has not improved ambient cooling 7

314 and the overall occupancy rate for the gardens is low. The survey on residents experiences reveals that one-third of the residents never visit their sky gardens and no daily visitors are found, whilst the elderly and children were infrequent users of sky gardens. Still, residents expect more greenery, spacious garden spaces, and more amenity facilities in their sky gardens, and agree that sky gardens improve property prices. Nonetheless, more research is needed to confirm whether sky gardens can improve social outcomes and perceptions. Recommendations are that the design of sky gardens needs to include consideration of specific environmental and social functions. Sky gardens located at relatively low levels emphasize building permeability with sufficient headroom. Sky gardens at high levels serve the purposes of recreation, social gathering, and ambient cooling. Sky gardens with wider spaces and attractive amenities act like naturally-ventilated sky clubhouses, and those with extensive planting integrate well with circulation spaces at multi-levels of a building. REFERENCES Chen, W. Y. and Jim, C. Y., External Effects of Neighbourhood Parks and Landscape Elements on High-rise Residential Value Land Use Policy, 27, Chien H. T. and Wang M. S., Environmental Behaviour Analysis of High-rise Building Areas in Taiwan, Building and Environment, 34, Connell J., The Purest of Human Pleasures - The Characteristics and Motivations of Garden Visitors in Great Britain Tourism Management, 25, Delvin, A. S. and Zaff, J., 1998 Sense of Community in Housing for the Elderly, Journal of Community Psychology, 26(4), Givoni B., Impact of Planted Areas on Urban Environmental Quality - A Review, Atmospheric Environment, 25B(3), Goddard M. A., Dougill A. J. and Benton T.G., Scaling Up from Gardens - Biodiversity Conservation in Urban Environments, Trends in Ecology and Evolution, 25(2), HKSAR Buildings Department, Lands Department and Planning Department, Joint Practice Note No.1 Green and Innovative Buildings, HKSAR. HKSAR Development Bureau, Legislative Council Panel on Development Discussion Paper: Review of Measures to Promote Green Features in Building Developments, HKSAR. HKSAR Buildings Department, Consultancy Study on Building Design that Supports Sustainable Urban Living Space in Hong Kong, HKSAR. HKSAR Council on Sustainable Development, Invitation for Response Document: Building Design to Foster a Quality and Sustainable Built Environment, HKSAR. Huang, S. C. L., A Study of Outdoor Interaction Spaces in High-rise Housing, Landscape and Urban Planning, 76, Ip C. M., Sky Garden Design in High-density High-rise Residential Development. Thesis (MSt. IDBE). University of Cambridge. Jim C. Y. and Lo A. Y., Willingness of Residents to Pay & Motives for Conservation of Urban Green Spaces in the Compact City of HK, Urban Forestry & Urban Greening, 9, Kaplan R. and Matsuoka R. H., People needs in the urban landscape - Analysis of Landscape and Urban Planning contributions, Landscape and Urban Planning, 84, Kuo F. E., Sullivan W. C. and Taylor A. F., Views of Nature and Self-discipline- Evidence from Inner City Children, Journal of Environmental Psychology, 22, Kweon, B. S., Sullivan, W. C. and Wiley, A. R., Green Common Spaces and The Social Integration of Inner-city Older Adults, Environment and Behaviour, 30, Lee J. and Min B., Children s Neighbourhood Place as a Psychological and Behavioural Domain, Journal of Environmental Psychology, 26, McCurdy L. E., Winterbottom K. E., Mehta S. S., and Roberts J. R., Using Nature and Outdoor Activity to Improve Children s Health, Health Care, 5, Niu, J., Some Significant Environmental Issues in High-rise residential Building Design in Urban Areas, Energy and Buildings, 36, Wong, N. H. and Yuen, B., Resident Perceptions and Expectations of Rooftop Gardens in Singapore, Landscape and Urban Planning, 73,

315 BUILT ENVIRONMENT MODELLING AND HIGH PERFORMANCE ENVELOPE DESIGN Dr Tony NT Lam 1, Dr Kevin KW Wan, Dr Trevor SK Ng, Dr Vincent SY Cheng Building Sustainability Group, ARUP, Level 5 Festival Walk 80 Tat Chee Avenue, Kowloon, Hong Kong SAR Haico Schepers Architectural Science and Engineering, ARUP, Level Kent Street, PO Box 76 Millers Point, Australia 1 Corresponding Author ngan-tung.lam@arup.com, Tel: (852) , Fax: (852)

316 BUILT ENVIRONMENT MODELLING AND HIGH PERFORMANCE ENVELOPE DESIGN ABSTRACT Built Environment Modelling (BEM) has been adopted successfully in recent project development. Innovative design strategies allowed building performance to go beyond the LEED or BEAM plus building assessment systems. New generation of BEM has been made by incorporating the high performance envelope optimization strategies with BEM techniques. Firstly, an envelope design in which the environmental analyses results from BEM are represented graphically, and parametrically transformed into a range of architectural options. Secondly, parametric envelope design options can be integrated with the BEM to evaluate the architectural design in energy performance basis. The novel integration between the architecture and engineering could give better information to the design and drive towards an optimized solution. Keywords: Built Environment Modelling; Façade Optimization, Building Energy Performance 1. BACKGROUND & BEM IMPORTANCE Built environment quality and energy performance are the key design drivers in nowadays building industry. There is a trend that the demand of the Built Environment Modelling (BEM) will increase gradually; the architects and building physics engineers will want to know more environmental performances of the built environment in order to have the most comfortable and energy efficient design. Therefore, there is a need to have reliable BEM interface which allows the users to have comprehensive environmental modelling, and provides efficient design input and information exchange. Next generation of BEM is discussed in this paper. There are two key features of this BEM; firstly, it provides reliable and efficient graphical results to illustrate the environmental performances of various envelope design options. Architects would find it easy to understand the performance of their design, while engineers can easily identify the design improvement approaches; secondly, it is capable to integrate various environmental factors to conclude an overall performance. In addition, it can conduct the automatic design optimisation, which greatly streamlines the design process. 2. HIGH PERFORMANCE ENVELOPE OPTIMIZATION 2.1 BENCHMARK FOR HIGH PERFORMANCE FAÇ ADE DESIGN To assess the thermal and energy performance of different building envelopes, heat gain through the building envelopes would be the crucial parameter affecting the overall performance of a façade design. In subtropical Hong Kong, the heat gain on building envelope could contribute significant part of the total building cooling load. An efficient building envelope design could limit the overall heat gain during the summer months but capturing the solar heat and preventing the heat loss during the winter seasons. The overall thermal transfer value (OTTV) was adopted as the benchmark to govern the building overall heat transfer in high performance building facade design [Building Department 1995 and 2011]. In general, three components of heat gain 2

317 through the building envelope need to be considered conduction through opaque surface, conduction through glass and solar radiation through glass (Yang et al., 2008). In general, the OTTV for the external walls is determined by: OTTV = (Qw + Qg + Qs)/At = [(Aw Uw TDeq) + (Af Uf DT)+(Af SC SF)]/At (Eq:01) where Qw is the heat conduction through opaque walls; Qg is the heat conduction through windows; Qs is the solar heat through windows; Aw is the area of opaque walls; Uw is the U-value of opaque walls; TDeq is the equivalent temperature difference; Af is the area of fenestration; Uf is the U-value of window, DT is the temperature difference between exterior and interior design conditions; SC is the shading coefficient of window; SF is the solar factor for the particular orientation; At is the gross area of the walls = Aw + Af. Solar heat gain is usually the dominant component in the total building envelope heat gain determination and hence the corresponding cooling demand. Microclimate analysis in terms of the seasonal solar positions, facades irradiation and solar heat gain analysis would often be considered in sustainable building designs (Figure 1). In the context of Hong Kong, for the sake of the promotion of the building sustainability and achieving the energy efficiency targets, the stringency of the statutory OTTV has been improved to not exceeding 24W/m2 for the building tower in 2011(30 W/m2 before the amendment since 1995) [Building Department, 1995 and 2011]. To lead the building industry towards a more sustainable design, the governmental Architectural Services Department (ArchSD) targeted to achieve OTTV for all new projects no more than 18W/m 2 in 2012 on top of the current building regulations [ArchSD, 2012]. The Leadership in Energy and Environmental Design (LEED) green building assessment framework has established a spectrum of key criteria for sustainable building designs and established the baseline requirement for the building envelope and the energyrelated systems based on the ASHRAE 90.1 [ASHRAE, 2007]. An analysis has been made to investigate the equivalent OTTV values of the ASHRAE baseline model in the subtropical climates, an OTTV of 22-23W/m 2 was found for generic high-rise office building, which is more stringent than the current statutory requirement. Parametric façade optimization has been adopted to drive the building envelope designs beyond the statutory and LEED requirements. Key parameters that could optimize a sustainable and energy efficient building facades were investigated. Figure 1: Microclimate and Solar Irradiance Analysis 3

318 2.2 HIGH PERFORMANCE FAÇ ADE DESIGN - PARAMETRIC ANALYSIS A high performance facade could limit the envelope heat gain during the summer time and utilize the passive solar heat gain during the winter seasons (Lam et al., 2008). In the subtropical climate like Hong Kong, major design consideration is summer heat gain and cooling requirement. Space heating is not significant especially for airconditioned commercial buildings with large internal loads of lighting, equipment and people. Three major parameters that could drive a high performance building façade and advanced OTTV are considered, these were the window shading coefficient, horizontal shading and vertical shading. Wall insulations and the window-to-wall ratio would have the impact on the conduction heat gain and heat loss. For simplicity of this study, analysis would be focus on the façade solar heat gain, and therefore, not considered. A high-rise building project in Hong Kong is presented as an example for parametric façade optimization. The building is 64-storey with curtain walling design, floor-to-floor height 4.2m and 52% window-to-wall ratio. Integrated glazing unit (IGU) with SC=0.3 and U-value=1.6W/m2K are the major glazing of the curtain walling design without shading provided. An OTTV of 24W/m 2 was determined and acts as a baseline for the comparative study. Parametric study of different SC values and their corresponding OTTV has been conducted to carry out the building façade optimization. In the selected case study, it was indicated that the improvement of the SC value from 0.3 to 0.25 could improve the OTTV from 24 to 20W/m 2 K. In order to meet the ArchSD recommendation, a SC value of approximately 0.22 would be required to achieve the ArshSD target of 18W/m 2 K. An extremely designs of the SC=0.19 could bring the overall OTTV beyond the LEED/ASHARE requirement without accounting the contribution of the shading designs. Figure 2: Impact of the Shading Coefficient on OTTV Performance Either the vertical or the horizontal shading designs would contribute an external shading multiplier (ESM) discount factor for the solar heat gain reduction. Optimizations of the lengths of the vertical sidefins and the horizontal overhangs were conducted to determine the corresponding OTTV values from the original designs. Parametric values of vertical sidefins length at 500mm, 1000mm and 1500mm and its corresponding OTTV advancement were determined. It was indicated that the vertical sidefins would effectively block the solar heat gain for period and locations with low solar altitude, suggesting that the vertical shading would help to block the direct solar efficiently at the sunrise and sunset period in Hong Kong. In the selected case study, a one-meter length of the vertical sidefins could improve the OTTV by 7%. The OTTV improvement by the vertical sidefins could be further improved by reducing the spatial separation of the sidfins but this would lead to the reducing the visual angle, which would be the major concerns in perspective of architectural designs. Similar analysis has been done for the horizontal shading and overhangs depth of 800mm, 1100mm and 1400mm and determine its corresponding OTTV. A 800mm of the horizontal overhang could improve 4

319 the OTTV by 12% and a 1100mm could improve the OTTV by 20%. It is interesting to observe that the OTTV performance of a 800mm overhangs would be similar to a 1500mm sidefins. In general, a one-meter horizontal shading could improve the OTTV by 17-18%. Among those three proposed strategies to optimize a high performance façade design, it is clear to observe that the shading coefficient would be the most effective strategy in reducing the building envelope heat transfer followed by the horizontal shading and then the vertical shading in the context of the subtropical Hong Kong. It is envisaged that the ranking would be the same in the similar climates but further work is required in climates where heat loss would be the dominant factors. Calculations of the OTTV should be revisited. Figure 3: Vertical and Hhorizontal shading Optimization 2.3 SUSTAINABLE FAÇ ADE DESIGN MAP A sustainable façade design map was developed to investigate the correlations between the contribution of the shading coefficient, vertical and horizontal shading and the impact on the OTTV. The map would be useful to gives the designers and the building professions to have an ideas about the building energy efficiency performance through glazing selection and different shading strategies. The different colors represented different stringency of the SC values and the corresponding OTTV value are indicated the bubble. It was indicated that in the context of subtropical climates, improvement of the SC would be directly related to the reduction of the solar heating gain. An improvement of the SC value from 0.3 to 0.2 could reduce the building heat transfer by 30% (where WWR =52%). The x-axis of the map represents the increasing length of the overhang where the y-axis the depth of the vertical shading and their combinations on the diagonal. It was indicated that horizontal shading could be slightly more efficient than the vertical shading in subtropical climates in consideration of the high solar altitudes. It was indicated that the effect of the overhang or the sidefins could be overlapped and further enhancement of would appear until one variable pass the threshold limit. In general, designs of 1000mm of horizontal shading could contribute 17-18% improvement in reduction of the building envelope solar heat gain where 1000mm of the vertical shading could contribute 7-8% reduction. In our other study, the shading effect of the vertical sidefins would very much depend on the spatial separation distance between the sidefins. The performance of the overall heat gain reduction could be improved 4% more (up to 12%) if the sidefins spatial separation reduced by half at current case. It is envisaged that the approaches the sustainable façade design map would be applied to other locations. 5

320 Figure 4: Sustainable Façade Design Map 3. ENVELOPE OPTIMIZATION INTERACTION WITH ENERGY PERFORMANCE The section above discusses the high performance envelope design with parametric analysis, in order to provide design information to the architects to optimize the environmental performance, by having the better graphical presentation and visualisation. During the design, sometimes it is difficult for the design team to handle a large number of design parameters. For example, the architects and building physic engineers need to take care of facade performance in terms of solar heat gain, daylight access, glare and natural ventilation, etc. The design team may find it complicated to strike for the balance of the design. There is a need to have an overall conclusive description of the environmental performance of each design scheme. Energy performance of the facade scheme is one of the key parameters to be considered as the optimisation indicator. This section introduces the design tool Facade Design Explorer, which streamlines the envelope design through advanced BEM technique. The Facade Design Explorer (FDE) is a set of tools/ components that link together Rhino/Grasshopper/Salamander with EnergyPlus and Radiance. Rhino is the software to create the building/ facade 3D geometry; Grasshopper is a graphical algorithm editor integrated with Rhino, and allows users to input the formula to govern the performance they focus on- this facilitates the users to revise the geometry easily and see the environmental impact for various schemes; Salamander is the Rhino built-in tool to define the materials types, which is useful for communicating with EnergyPlus and Radiance. The FDE, a small 'optimizer' application, drives the process to generate geometry options in Grasshopper which are then analysed in EnergyPlus and Radiance. 3.1 FDE S PRINCIPLE The FDE is applied to solve the design problem in balancing between daylight availability and cooling demand through various façade designs. It is capable to handle a number of façade zone variables including: Façade height, width and orientation Size and position of horizontal or vertical shades Number of horizontal or vertical shades 6

321 Size and position of window Each individual variable gives impact to daylight access, sun shading and cooling demand; overall energy performance (maximum daylight-saving and minimum cooling demand) would be the indicator to inform the optimized façade design. Below is the basic outline of the process of FDE operation: Figure 5: FDE Basic Process Firstly, the façade optimizer will work as a central processor to define site weather, façade materials, glass properties, analysis target and output options, etc. Through Rhino, 3D model including surrounding context, project building, façade details, etc are created. Rhino, Grasshopper & Salamander will create the geometry and material file, and then translate to EnergyPlus and Radiance for cooling demand and daylight modelling, respectively. The modelling results are fed to the optimizer to check the difference from the target, and further process the iterations by informing Grasshopper for geometry change. 3.2 FDE S OUTPUT In FDE, the user can define the façade variable range, e.g. horizontal shade length and interval. FDE can either manipulate that input variable until it reaches the target value, or do a number of iteration defined by the user. Figure 6 shows the analysis output of a range of horizontal shade lengths for a building. Based on each shading length, the FDE calculates the daylight factor and cooling demand of all sampling points (e.g. the center point of each room). The design scheme with maximum sampling points fulfil the daylight and cooling demand targets is the optimized scheme. In Figure 6, it is observed that iteration no. 9 with horizontal shade of 250mm length can give best overall energy performance for the building, under the particular function and local climate. FDE is also applied to optimize the design for each individual façade part, e.g. orientation, and high, middle & low levels, based on the local weather condition and surrounding shading. Figure 7 is the example of the building façade responding to the energy performance, surrounding shading and local climate. 4. CONCLUSIONS The paper outlines a number of key characteristics of the new generation of BEM techniques. Its impact on design practice is briefly explored through parametric analysis of high performance building envelope design strategies and optimizations. This BEM is capable to solve the envelope design problems in technical information exchange and handling a large number of façade zone variables. The architects and engineers can easily identify the design implications and make decision by BEM s 7

322 graphical outputs and automatic optimization. The BEM is targeted to streamline the design process and handle the complicated envelope design cases. Figure 6: Graphical Output of FDE Figure 7: Visualization Output of Optimized Façade 5. REFERENCES ArchSD Sustainability Report From planning to design through operation to maintenance. Architectural Services Department (ArchSD), Hong Kong SAR. ASHRAE ANSI/ASHRAE/IESNA Standard , Energy Standard for Buildings Except low-rise Residential Buildings. Atlanta, GA: American Society of Heating Refrigerating and Air-Conditioning Engineer. Building Department Code of practice for overall thermal transfer value in buildings. Buildings Department, Hong Kong SAR. Building Department APP-67. Energy Efficiency of Buildings-Building (Energy Efficiency) Regulation. Buildings Department, Hong Kong SAR. Lam J.C., Wan K.K.W, Tsang C.L., Yang L., Building energy efficiency in different climates. Energy Conversion & Management 49(8): Yang L, Lam J.C., Tsang C.L Energy performance of building envelopes in different climate zones in China. Applied Energy 85(9):

323 MARKET DRIVERS ON THE TRANSFORMATION OF GREEN BUILDINGS IN HONG KONG Dr. Raymond Yau 1 Fellow and Director, Building Sustainability, Ove Arup & Partners HK Ltd., Hong Kong Director, Hong Kong Green Building Council, Hong Kong Dr. Jimmy Tong Associate, Building Sustainability, Ove Arup & Partners HK Ltd., Hong Kong Dr. Trevor Ng Senior Consultant, Building Sustainability, Ove Arup & Partners HK Ltd., Hong Kong 1 Corresponding Author Raymond.yau@arup.com, Tel: (852) , Fax: (852)

324 MARKET DRIVERS ON THE TRANSFORMATION OF GREEN BUILDINGS IN HONG KONG ABSTRACT Hong Kong Green Building Council (HKGBC) is proposing a holistic approach based on demand side management of electricity consumption to reduce 30% of the absolute amount of the electricity used in buildings in 2030, and this campaign is called HK3030. This holistic approach involves classifying the building stocks according to their size, age, usage, and ownership, and tailoring strategies and policies that specifically target the sweet spots in each of them. The objective of this paper is to identify necessary actions, policies and potential costs towards achieving the HK3030 targets by presenting the market drivers on the transformation of green buildings in Hong Kong. In this paper, a baseline scenario (BAU) is used to explain the current situation and the prediction with BAU practice. A quantitative study on the necessary technologies, designs, and extent of behaviour changes to realize the goals is provided. Furthermore, the HK3030 energy scenario and life-cycle and cost scenario are presented to illustrate how HK3030 is achievable by measures proposed by HKGBC. This part of the study is enhanced by a survey on potential financial implications of pursuing these goals. Finally, a review on policy options and subsequently policy recommendations are listed to show how to facilitate the entire community to achieving the targets. Keywords: Cost; Energy; Green Building Policy; Holistic Approach; Scenario Studies. 1. INTRODUCTION To cope with the global climate change challenge and to deal with the increasing demand of electricity consumption, Hong Kong has the imperative to explore options to meet the greenhouse gas (GHG) reduction target. Since buildings in Hong Kong consume over 90% of the electricity and account for more than 60% of the GHG emitted citywide, there shall be a vast potential for the building sector in contributing to the GHG reduction target 2. Therefore, Hong Kong Green Building Council (HKGBC) proposed HK3030 Campaign, a holistic approach based on demand-side management of electricity consumption 3. It proposes a reduction of 30% of the absolute building electricity consumption by 2030, as compared to the level of With the technological advancement and government supports, the campaign is considered to be an aggressive yet achievable target. It will drive Hong Kong to a more responsible metropolis and will be a major step towards a sustainable built environment. Arup is commissioned by HKGBC to conduct researches on energy consumption trends in Hong Kong, possible strategies and policies for achieving HK3030 target, and 2 Environmental Bureau, HKSAR Government, Hong Kong s Climate Change Strategy and Action Agenda. Hong Kong. 3 Market Drivers and Feasibility for Green Buildings-Green Buildings Policies Review and Application to Hong Kong, 2012, HKGBC, Hong Kong. 2

325 required costs towards the target. With the projection of increasing building stocks and higher energy consumption per capita, HK3030 Campaign is equivalent to a reduction of 49% of the projected electricity consumption level in METHODOLOGY THE OVERARCHING APPROACH The main objective of this paper is to identify the necessary actions for the achievement of HK3030 target by presenting the market drivers on the transformation of green buildings in Hong Kong. In order to achieve this aggressive yet achievable target, an overarching approach is needed. Market Drivers Regulatory Means Market Incentives Other Policies (education, training, promotion, etc.) Pathway Technology Advancement and Uptake Behavior Change Target: 30% Absolute Reduction from 2005 level by 2030 Figure 1: Market Drivers, Pathway, and Target 4 The interactions among the market drivers, pathway and the target are shown in Figure 1. It illustrates how market drivers determine the driving forces towards HK3030. The pathway is also essential, as it determines the feasibility of the campaign. Once the mechanisms between the market drivers and HK3030 target are identified, energy models for various building types in Hong Kong are developed. The models allow the construction of possible energy reduction scenarios, which predict the realistic reduction on energy consumption level by the year of The scenarios are then employed to propose the possible pathways towards HK3030. After that, the cost associated with each pathway is analyzed and compared with each other. Besides cost analysis, a qualitative analysis is also conducted to assess the strategies in details. 4 Adapted from Market Drivers and Feasibility for Green Buildings-Green Buildings Policies Review and Application to Hong Kong, 2012, HKGBC, Hong Kong. 3

326 Finally, a set of effective and efficient market drivers needed to achieve HK3030 target is recommended as a low-hanging fruit. The process is illustrated in Figure 2. HK3030 Energy Scenario Cost Analysis HK3030 Target Pathway Market Drivers Energy Modeling and Calibration Qualitative Analysis Figure 2: Identification of Key Market Drivers for Achieving HK3030 Target 3. ENERGY DEMAND SCENARIOS THE PATHWAY STUDY 3.1. CURRENT BUILDING ENERGY CONSUMPTION To study the current building energy consumption in details, buildings are categorized into two main segments, which are residential and commercial buildings, mainly due to their differences in energy consumption intensities and pa tterns. These two types of building are further divided into several subcategories to determine the major energy consumptions in each building stock and to determine the variation in energy consumptions among all stocks. Public Housing Commercial Office Building Types Private Housing Subsidized Flats Storage Hotel Others Public Services Restaurant Other s Residential Residential Health Retail Floor area 1,000m kwh/m 2 /yr 500 kwh/m 2 /yr 1000 kwh/m 2 /yr EUI (Energy Use Intensity) Figure 3: Current Building Energy Consumption in Hong Kong 5 5 Data for energy consumption and floor area are collected from the following sources: Data published by Electrical and Mechanical Services Department (EMSD) and other government departments Energy audit results from private and public sources HKGBC benchmarking exercises Voluntary disclosures from private developers and energy data from utilities companies 4

327 Energy model for each building type is constructed to identify its energy saving potentials. To ensure that the models have high levels of accuracy, they undergo calibration processes using the collected real-measured data. By analyzing the energy saving measures for each type of building, the effective energy saving scenarios for overall buildings can be developed. Figure 4 shows a waterfall chart for a typical green building design approach in Hong Kong. The listed measures outline the overall approach to achieve higher energy efficiency in buildings. By employing moderate designs, advanced technology, and inputs from end users, the energy consumption of a typical building in Hong Kong can be reduced by 37%. Figure 4: Energy Saving Scenario of a Typical Building in Hong Kong DIFFERENT BUILDING CONDITIONS In practice, the energy consumption levels are not only dependent on the purpose of the buildings, but also their conditions. In order to identify the realistic pathways towards HK3030, an extensive study on buildings with different conditions is essential. For this study, buildings are divided into the following three categories according to their decommissioning, refurbishments and infrastructures: Existing buildings existing buildings that have minimum opportunities for energy saving strategies Retrofitted buildings existing buildings that possess infrastructures for energy saving strategies Supplementary Information : LPD Lighting Power Density LPD = Total Lighting Wattage/Internal Floor Area LPD Reduction Measures: -Existing Building -Reduced Lux Level - High Efficiency Luminaires - High Efficiency lighting fixture -Light pattern and layout optimization -LED lighting 6 Please refer to supplementary information on LPD and Chiller COP in Figure 5 and 6 ~15-20 W/m 2 ~10 W/m 2 ~6 W/m 2 Figure 5: Supplementary Information for LPD 5

328 New buildings buildings that are newly developed, which follow the regulations published by Hong Kong Government The current energy consumption level and possible target for each building category are shown in Figure 7. New buildings have the largest potential for energy saving strategies, as their developments are governed by the latest codes published by Hong Kong government. However, the projection estimates the portion of new buildings to be only 16% in COP Supplementary Information - Chiller COP Reciprocating COP (Coefficient of Performance): Cooling Power/Electrical Power Screw Centrifugal Reciprocating Air Cooled Water Cooled Oil Free Screw Technology Trend * Data collected from various chiller suppliers, updated in 2013 Centrifugal Centrifugal Typical HK Building Figure 6: Supplementary Information for Chiller COP On the other hand, the study reveals that the existing and retrofitted buildings account for most of the building energy consumptions in Hong Kong. Therefore, the energy reduction targets set for these two building categories are crucial for the achievement of the HK3030 target. Energy Usage in Annual Electricity Usage per Unit Area (kwh/m 2 /yr) Housing Authority Public Rental Flats Housing Authority Home Ownership Scheme Existing Buildings Retrofitted Buildings Brand New Buildings Private Residential Area (m 2 ) Private Office Restaurant & Retail Others Eg. Hospitals, Villas, Recreation Centres, etc. Figure 7: Targets for Different Building Conditions 3.3. FORECAST ENERGY DEMAND IN 2030 A robust and consistent baseline of energy consumption scenario is developed to understand the trend of building energy consumption based on Business as Usual (BAU) practice. It forms a foundation for the development of energy saving strategies needed to achieve the HK3030 target. In order to project building energy consumption level to the year of 2030, factors that are highly correlated to the consumption level have to be determined. Several possible affecting factors, such as Gross Domestic Product (GDP) growth, population and other social factors are considered in this study. 6

329 The most significant affecting factors are then used to project the energy consumption trend, which is illustrated in Figure 8. The trend serves as the baseline for energy saving strategies towards HK3030. The BAU-based projection estimates that HK3030 target is equivalent to a reduction of 49% of the electricity consumption level in Building Energy Consumption (GWh) BAU 47,492 GWh Base year 30% reduction from 2005 level Interim Target 49% reduction HK3030 Target 24,185 GWh Figure 8: Possible Energy Consumption Trends in Future 4. DEVELOPMENT OF COST MODEL A preliminary life-cycle cost model forecasting the required cost for zero carbon building achievements in Hong Kong is constructed. The cost models of all strategies are then developed and c ompared with each other. The comparison allows the costeffectiveness of each strategy to be analyzed. It also assists the decision making for policy recommendations. The cost for implementing each strategy is normalized by its reduction in energy consumption level per year. This method allows a direct comparison on t he cost effectiveness of the energy saving strategies, as the lower the normalized value, the more cost-effective the strategy is. Required Cost for Energy Savings [$/kwh] 300 Retail and Entertainment Buildings Office Buildings % 10% 20% 40% 60% 100% Energy Reduction Level (as compared to the level of 2005) Figure 9: Required Costs for Energy Savings 7

330 Figure 9 shows that no significant capital investment is needed to achieve the first 20% of energy reduction. However, the next 20% of the reduction requires much higher investment, due to the utilization of advanced technology in buildings. Once the energy reduction reaches the level of 40%, the required cost for further reduction declines as the reduction is mainly achieved by adopting renewable energy technologies in buildings, such as roof photovoltaic panel, wind turbine, etc. 5. DEVELOPMENT OF HK3030 POLICY RECOMMENDATIONS THE MARKET DRIVERS In the first stage of the project, Arup has identified preliminary market drivers for the transformation of green buildings in Hong Kong, which includes: The coverage and stringency of green building regulations and policies The availabilities of incentives and financing mechanisms to promote the development of green buildings The development of benchmarks, online reporting tools and objective measures of plant efficiencies (e.g. chiller efficiency and pump efficiency) The introduction of mandatory energy audits and retro-commissioning The implementation of smart meters and other relevant green building technologies The enhancement on green building specialist trainings and promotion on greener lifestyle In the end of this research, three types of policy recommendations will be delivered, and they will take the form of: Regulatory policy recommendations - regulatory policies that forces the utilization of advanced technologies and designs, and necessary behaviour change towards HK3030 target Incentives policy recommendations - incentives that promote the required technologies, design and behaviour change to achieve the target Other policy recommendations - strategies on education, trainings, promotions, etc. The policy recommendations will be m ade in the context of the current policy framework and future developments for a shortlist of low-hanging fruits. Recommendations will be given on how to best integrate with: Overall policy framework - feasible quantitative standards for the short- and long- terms development of Building Energy Code (BEC) and Energy Audit Code (EAC) will be established Incentive schemes, such as Gross Floor Area (GFA) incentives and Environment and Conservation Fund (ECF) New funding mechanisms, such as loans, Energy Service Company (ESCO) Funding and performance contracts 6. CONCLUSION In this paper, a baseline scenario is constructed to explain the current and predicted energy consumption levels. Quantitative analysis on the required technologies, designs, and behavior change towards the target is presented. Furthermore, HK3030 energy 8

331 scenarios and life-cycle, and cost scenarios are also delivered to illustrate how HK3030 target can be achieved using measures proposed by HKGBC. Finally, a review on policy options and the subsequent policy recommendations are listed to facilitate the entire community in achieving the target. 7. ACKNOWLEDGMENT This research is supported by Hong Kong Green Building Council (HKGBC), especially its team from Industry Standards and Research Commitee. The authors wish to thank Tao Li, Erwanda Nugroho and Arup Building Sustainability Team for their supports and assistances in this project. 9

332 A Review on Barriers, Policies and Governance for Green Buildings and Sustainable Properties T.M. Leung and C.K. Chau 1 Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong Thomas P. Lützkendorf and M. Balouktsi School of Economic and Business Engineering, Karlsruhe Institute of Technology, Germany 1 Corresponding Author chi-kwan.chau@polyu.edu.hk, Tel: (852) , Fax: (852)

333 A Review on Barriers, Policies and Governance for Green Buildings and Sustainable Properties ABSTRACT The worldwide sustainability movement has led to growing demands for green buildings and sustainable properties. In response, many governments took the leading role in green or sustainable building development by making public buildings greener. Voluntary initiatives have also been emerged to encourage green building development. However, the market penetration rates of green or sustainable buildings are often far below anticipation. This is due to different barriers to green development. Besides, the benefits arising from green buildings do not appeal attractive enough for or may not be realized by stakeholders. In order to acquire deeper penetrations, policies and institutional governance have to be formulated to encourage more green building developments. This paper is intended to reveal the types of policies that have been implemented by various governments to overcome different types of barriers to green or sustainable building developments. Also, potential government policies and institutional governance have been identified by reference to those implemented for improving building energy efficiency. Keywords: Green Buildings; Sustainable Buildings; Policy; Barriers; Instruments. 1.0 INTRODUCTION Buildings consume various natural resources and produce a lot of unwanted emissions. In response, many green buildings have been evolved with an objective of minimizing resources use and unwanted emissions. Although green buildings have been growing in numbers, the rate of increase is lower than anticipated. A number of barriers to green building developments have been identified. Up to date, only a limited number of government policy instruments have been implemented to overcome these barriers. Accordingly, this paper intends to identify the types of policies and governance that have been implemented to overcome these barriers. Also, potential government policies and institutional governance will be identified by reference to those implemented for improving building energy efficiency. In fact, green buildings represent an approach for improving sustainability in the construction sector; they focus on the issues of resource conservation as well as climate and environmental protection and are expected to contribute to better health, ease and comfort. Sustainable buildings go beyond these issues and incorporate aspects of life cycle cost, recoverability, functional and technical quality as well as user satisfaction. Although this contribution focuses on the topic of green buildings, it also brings forward issues related to sustainable buildings. In Germany, whose development is compared with that of Hong Kong, the transition to consideration of sustainable buildings has already been accomplished. In doing so, questions concerning resources conservation as well as climate and environmental protection are an essential aspect of the problem. 2.0 BARRIERS TO GREEN BUILDINGS Many barriers have been found to hinder the development of green buildings. Table 1 lists different types of these barriers 2.1 COMMODITY-RELATED BARRIERS 2

334 Improper definition of green building within a policy may hinder green development. Green buildings also encompass widely diverse environmental issues with incompatible measurement scales. The assessment of some environmental issues may involve some value judgment. They may not be easily appreciated by stakeholders. Often, detailed definition of green buildings has been laid down within building environmental assessment schemes. Unfortunately, highly technical character of credit definitions, aggregation of radically different types of elements into a single score, and the bureaucratic complexity of the assessment method creates additional knowledge barriers to green building (Schweber, 2013). On the other hand, there is also progress being made in this direction. With the international standards ISO 15392:2008 Sustainability in building construction - General principles and ISO :2011 Sustainability in building construction - Sustainability indicators - Part 1: Framework for the development of indicators and a core set of indicators for buildings foundations have already been laid. Although these standards formulate the requirements for sustainable buildings and determine specific assessment criteria, are still not well enough known and receive in general little attention. Barrier Categories Barriers Commodity-related barriers Definition of green buildings Funding issues Quantification of benefits Split incentives and appropriability Lack of knowledge and awareness Risk and uncertainties Process-related barriers Lack of measureable requirements Lack of communication among project team members Organization and personal Lack of commitments from the administrative leaders behavioral barriers Lack of communication between the public and administration Personal resistance to change Lack of incentive TABLE 1: BARRIERS TO GREEN BUILDING DEVELOPMENT The prime concern for a majority of building investors/owners is whether sustainable development will incur higher first costs regardless of whether long-term benefits will be offered. Even some stakeholders may realize some of the operating and intangible benefits of green buildings, many are uncertain about the size and type of those benefits (Issa et al., 2010). So far the real estate industry has mostly focused on demonstrating the economic benefits of energy efficient buildings. There are some first results (European Commission, 2013). The problem is that often the physical characteristics of the buildings are not captured in the databases of transactions - this complicates empirical analyses. On the other hand, incentives may not be properly appropriated among stakeholders. If the investors will sell the properties after they have built, they may not want to invest in green buildings. Tenants may not invest if they are likely to move out before fully benefiting from the benefits arising from green buildings. The lack of public awareness can be a barrier to green buildings (Samari et al., 2013). A lack of knowledge of constructors / designers on green buildings creates additional barrier. At the same time, investors may see risk and uncertainties when making decisions on green or sustainable buildings. Green buildings often involve application of new technologies. They may pose risks of not deliver the desired performances in a timely manner. Uncertainties about the costs and benefits also create barriers in getting across the financial information necessary to inform decision makers. 2.2 PROCESS-RELATED BARRIERS The process of developing green buildings itself can also create some barriers. The complexity of green buildings inherits practical difficulties in defining measurable requirements. The diverse nature of green building requires not only full cooperation and effective communication among project team members, but also requires close 3

335 interaction of suppliers, professionals and users. Green building design is prone to failure in the absence of a close interaction and effective communication among project team members. Besides, gaps between interactions and decisions during the process of construction and management could also be a barrier (Stevenson and Rijal, 2010). 2.3 ORGANIZATIONAL AND PERSONAL BEHAVIORAL BARRIERS There can be a general lack of incentives for investors to invest in green buildings. About one-third of surveyed companies in Hong Kong stated that the lack of incentives was the main barrier of engaging in voluntary environmental initiatives (Studer et al., 2006). Some barriers may be created by an organization itself. Lack of environmental protection commitments from the administrative leaders, as well as inadequate communication between the stakeholder and administrators could create barriers to green building development (Richardson et al., 2007). Individuals behavioral characteristics can also be barriers to green building development. Resistance to change was a barrier to implementation of energy efficiency measures (Nagesha and Balachandra, 2006). 3.0 POLICIES AND GOVERNANCE There are several possibilities to promote green building development. On one hand market forces can be used, on the other hand a state control can take place. For example, governments have to formulate various policies to overcome its barriers, and to remove disincentives. Table 2 shows different types of policies that can be applied to overcome different types of barriers for different actors. Barriers Policy Instruments Actors Definition of Green Buildings #Adoption of Green Building Labels Funding Issues #Grants and Loans Lack of Incentives #Density Bonus #Tax Credits #Expedited Permit Process *Eco Tax Split Incentives and Appropriability #Regulation on Property Valuation *Tenancy Law Lack of Knowledge and #Performance Rating Disclosure System Awareness #Mandatory Standards for Government Buildings #Free Technical Advices #Information on the Internet #Education and Training Programs *Green Building Audits *Desktop Advices/Assistance Targeted actors: 1. Developers, 2. Developer-Owners, 3. Individual Owners, 4. Tenant Users and 5. Contractors #Policies for Green Building *Potential Policies that can be transformed from those targeted at Building Energy Efficiency. TABLE 2: GREEN BUILDING POLICIES TARGETING DIFFERENT BARRIERS AND ACTORS 3.1 POLICIES TO OVERCOME THE BARRIER OF DEFINITION OF GREEN BUILDING A proper definition of green building is needed when formulating green building policies. One way to resolve this is to introduce a green building label. Yet, the label should give a specific definition so that even laypeople can easily understand. In Germany with the rating systems DGNB and BNB approaches for the assessment and certification of sustainable buildings have been developed. These include not only definitions, 4

336 assessment criteria and benchmarks but also facilitate the communication between client and contractor as well as the planning and quality control. 3.2 POLICIES TO OVERCOME FUNDING ISSUES Loan relief and grants can be provided for developers to reduce the initial cost required for green buildings. Internationally, there are many examples of provision of subsidized financing and insurance in related to energy efficient, green and sustainable buildings. Under Los Angeles Department of Water and Power Green Building Incentive, a grant up to US$250,000 would be awarded to buildings which met the LEED (Leadership in Energy and Environmental Design) standard. In Germany so far there are funding programs particularly for improving the energy performance, such the one supported by KfW Bank. Specifically, a report commissioned by WWF and E3G (Höhne et al., 2009) scored this energy efficient buildings package as the most successful policy with the most important green effects across a range of countries. 3.3 POLICIES TO OVERCOME LACK OF INCENTIVES Density bonus or height relaxation has sometimes been used as an incentive to encourage developers and developer-owners to invest in green buildings. Fulfilling the BEAM-Plus requirements was made as a pre-requisite for obtaining a density bonus in Hong Kong after In Germany, in some municipalities the allocation of land is subject to an obligation to construct energy-efficient buildings. Besides density bonus, taxation incentives can be used for promoting green building development. Tax credit has been employed in the US as a policy instrument to encourage more LEED certified buildings (DuBose et al., 2007). In Europe - including Germany - this issue has already been discussed - there are no concrete results yet. With an expedited permit process, developers will have the incentive to make the building greener because they can enjoy a reduction in cost. The Green Permit Program in Chicago guaranteed an expedited permit of 30 days if the building was LEED certified. 3.4 POLICIES TO OVERCOME SPLIT INCENTIVES AND APPROPRIABILITY To overcome the barrier of split incentives and appropriability, the questions of whether and to what extent the benefits of energy-efficient, green or sustainable buildings are already reflected in the purchase price are of high importance. In Germany for example the energy-related quality of buildings is already taken into account according to the national regulation of valuation (Meister and Dressel, 2012). 3.5 POLICIES TO OVERCOME LACK OF KNOWLEDGE AND AWARENESS Sellers and landlords can be required to display building environmental performance certificate to potential homebuyers or renters so as to address the issue of imperfect information when making home purchase or rental decisions. Since 2006, Korea had implemented a Housing Performance Rating Disclosure System for the purposes of ascertaining quality supply of housing, while promoting an increase in the supply of ecologically friendly housing. In Germany, over the past few years an energy certificate with information related to energy performance has to be submitted to every tenant or buyer. In public buildings these energy certificates must be hung up clearly visible. In the future, information on the energy quality will become part of the advertisement for rent and sale of buildings in magazines and newspapers. 5

337 Governments should assume a leading role in promoting green buildings. In many countries, like US and Germany, it is mandatory for government buildings to meet certain green building criteria. Specifically in Germany every new federal building must achieve the quality level SILVER based on the national sustainability assessment system BNB. Technical advices and assistance can be offered by governments or private organizations. Under the 2005 Ordinance in Oakland in the U.S., free technical assistance on green building development would be provided by the government to private sector. In Germany advising clients on matters concerning energy efficiency is financially supported. At the moment, programs are starting in individual municipalities to support the sustainability consulting and assessment in the construction of residential buildings (e.g. Hamburg). Furthermore, A lot of information is needed during the decision process of green building design / construction within a short time frame. To this end, internet has been considered to be one of the most effective channels to provide new information for green building design / construction (Thunselle et al., 2005). Via the Internet platform all the basics and tools for sustainable construction in Germany are publicly available. This includes information on construction products, LCA data, the long-term durability of components, etc. Educational and training programs can be organized for equipping building contractors or designers with the knowledge to develop green building solutions. In Germany, many universities offer master's programs for sustainable building. The organizations for architects and engineers incorporate the theme into their training programs. The public sector educates through special programs sustainability coordinators. 4.0 POTENTIAL POLICIES (I.E. CAN BE TRANSFORMED FROM THOSE TARGETED AT BUILDING ENERGY EFFICIENCY) 4.1 ECO-TAX AND TENANCY LAW Following the approach in promoting building energy efficiency, imposition of an ecotax on conventional buildings may indirectly encourage developers to make their building greener. Besides, the tenancy law for promoting energy efficiency may also be amended to allow homeowners to recover the additional costs required for making the building green. It helps overcome the barrier of split incentives. Landlords can be allowed to increase the rent until the costs of green building measures have been recovered in some cases - especially in the case of improving the energy quality of existing buildings. 4.2 GREEN BUILDING AUDITS AND DESK ADVICES Similar to energy audit policy in Germany, green building audits are required for providing building owners with more information about the technologies that are currently available for improving the environmental performances of buildings, as well as the associated costs and benefits. When it comes to desk advices, building owners can seek technical and financial advices from governments or semi-governmental organizations. The costs for provision of advices can even be subsidized or free. 5.0 UNRESOLVED ISSUES 5.1 RISK AND UNCERTAINTIES 6

338 One of the hindrances for developers for undertaking green building developments is that they may not know if they can get their investments back. Hitherto, there is still no specific policy to deal with this issue. In Europe, however, discussions have begun about whether and to what extent the insurance companies can develop special products to cover the performance risk. 5.2 QUANTIFICATION OF BENEFITS Many research studies have been attempted to quantify the intangible benefits brought by green buildings. However, there still exist methodology gaps in quantifying the intangible benefits of green buildings, in particular with regard to the accuracy of quantitative extrapolations of the research studies (Fisk, 2000). 5.3 PROCESS-RELATED, ORGANIZATIONAL AND PERSONAL BARRIERS There are no specific policy instruments which dealt with process-related, as well as other organization and personal behavioral barriers. Even though legal standards could produce positive results (Easterbrook, 1995), they might lead to suboptimal outcomes (Tenbrunsel et al., 1997). Extensive educational campaigns are also needed (Hoffman and Henn, 2008). Therefore, it is important to train not only architects and engineers, but also real estate professionals and valuers. At the KIT in Karlsruhe, since 2000 a chair for the training of real estate specialists in the subject area of sustainable construction exists. This was supplemented in 2012 by a chair for the integration of sustainability into the valuation in cooperation with RICS. 6.0 CONCLUSION This paper identifies various barriers to green building development and the policies implemented to overcome some of these barriers. Some potential policies that can be transformed from those targeting at building energy efficiency to green buildings together with some unresolved barriers have also been discussed. It is hoped that more studies will be conducted in future so as to help policy makers to formulate policy instruments to overcome these unresolved barriers. ACKNOWLEDGEMENTS The authors would like to thank the 2011/12 Germany/Hong Kong Joint Research Scheme for providing financial support by the Hong Kong University Grant Council and the German Exchange DAAD through Grant No G_HK034/11. REFERENCES DuBose, Jennifer R., Bosch, Sheila J., Pearce, Annie R., Analysis of State-Wide Green Building Policies. Journal of Green Building, 2(2), Easterbrook, G., A moment on the earth. New York: Viking. Erlandsson, M., Generic M.B., LCA-methodology applicable for buildings, constructions and operation services-today practice and development needs. Building and Environment, 38, European Commission, Energy performance certificates in buildings and their impact on transaction prices and rents in selected EU-countries, final report 7

339 Fisk, William J., Health and Productivity Gains from Better Indoor Environments and their Relationship with Building Energy Efficiency. Annual Review of Energy and the Environment, 25, Höhne, N., Burck, J., Eisbrenner, K., Vieweg, M., Grießhaber, L Scorecards on best and worst policies for a green new deal, Ecofys and Germanwatch, WWF and E3G, 8-9 Issa, M.H., Rankin, J.H., Christian, A.J., Canadian practitioners perception of research work investigating the cost premiums, long-term costs and health and productivity benefits of green buildings. Building and Environment, 45, Meister, D. and Dressel, K., Valuation of Real Estate in Germany. In Just, T. and Maennig, W. (eds.), Understanding German Real Estate Markets, Management for Professionals, Springer-Verlag Berlin, Heidelberg Nagesha, N., Balachandra, P., Barriers to energy efficiency in small industry clusters: multi-criteria-based prioritization using the analytic hierarchy process. Energy 31, Richardson, Gregory R.A., Lynes, Jennifer K., Institutional motivations and barriers to the construction of green buildings on campus: A case study of the University of Waterloo, Ontario. International Journal of Sustainability in Higher Education, 8(3), Samari, M., Ghodrati, N., Esmaeilifar, R.,, Olfat, P., Mohd Shafiei, M.W.. The Investigation of the Barriers in Developing Green Building in Malaysia, Modern Applied Science (2013), 7(2), Schweber L., 2013The effect of BREEAM on clients and construction professionals. Building Research and Information, 41(2), Stevenson, F. and Hom, B.R., Developing occupancy feedback from a prototype to improve housing production. Building Research & Information, 38(5), Studer, S., Welford, R., Hills, P., 2006.Engaging Hong Kong Businesses in Environmental Change: Drivers and Barriers. Business Strategy and the Environment, 15, Tenbrunsel, A., Wade-Benzoni, K., Messick, D., & Bazerman, M., The dysfunctional effects of standards on environmental attitudes and choices. In M. Bazerman, D. Messick, A. Tenbrunsel, & K. Wade-Benzoni (Eds.), Psychological perspectives to environmental and ethical issues. New Lexington Books, San Francisco. Thunselle, K., Erhorn Kluttig, H., Mørck, O., Ferrari, S., Fuentes, M., Jicha, M., Kaklauskas, A., Kauppinen, T., Triantis, E., Bringing Retrofit Innovation to Application in Public Buildings BRITA in PuBs. Deliverable D5 - Socio-economic Analysis on Barriers and Needs. 8

340 WATER CONSERVATION STARTING WITH WATER EFFICIENT DEVICES Lee Hong Nin, Kevin Engineer/Customer Services(Technical Support)3 Water Supplies Department, HKSAR 46/F, Immigration Tower, 7 Gloucester Road, Wan Chai, Hong Kong kevin_hn_lee@wsd.gov.hk

341 WATER CONSERVATION STARTING WITH WATER EFFICIENT DEVICES Abstract Water is one of the most valuable natural resources on earth. Although Hong Kong is fortunate enough to have access to adequate supply of clean water, as responsible citizens of the world, we all have an obligation to conserve this shared and irreplaceable treasure. The Government has also taken its responsibility in this global effort to reduce water demand. Following the promulgation of the Total Water Management Strategy in 2008, the Water Supplies Department (WSD) launched the voluntary Water Efficiency Labelling Scheme (WELS) in 2009 as one of the initiatives to achieve actual water savings. WELS for various groups of water-consuming appliances has been launched in phases. Four types of products have been launched since 2009 and the WSD is continuing to look for new products for inclusion in WELS. By providing consumers with information on water consumption through water efficiency grading, the scheme could help consumers select water efficient appliances and promote public awareness on water conservation.

342 1. BACKGROUND 1.1 WATER RESOURCES IN THE GLOBE Water covers 71% of the Earth s surface area, making it one of the most abundant natural resources by volume. However, over 97% of the Earth s water is in the oceans and only 2.78% of the world s water exists as fresh water. The abundance of salt water versus the scarcity of fresh water is a global water resource problem that humans have been working to resolve or at least to alleviate. Unfortunately, various human actions have been aggravating fresh water scarcity through population growth, pollution, overuse and inequitable access. The effect of population growth is apparent. People also bring about water scarcity by polluting existing supplies by domestic sewage, municipal waste, industrial effluent, deforestation, eutrophication and suspended particulate matter. Overuse of groundwater has become a major problem in various parts of the world. Also, the uneven geographical distribution of water resources as well as the impacts of natural disasters and change of climate conditions have been putting greater stress on the sustainability of our finite water resources. 1.2 SITUATION IN HONG KONG In Hong Kong, limited groundwater resources, geographical constraints of water supply (no sizeable river or lake), acute climate changes in recent years and considerable variation of annual rainfall exists contribute to the fresh water scarcity. At present, the local fresh water collected from natural precipitation can meet on average 20% to 30% of our total fresh water demand. To make up the shortfall, the Government of the Hong Kong Special Administrative Region (HKSAR) (the Government ) has adopted significant water management measures by constructing new impounding reservoirs, using seawater flushing and increasing import of Dongjiang water from the neighbouring Guangdong Province. The per capita consumption of potable water 1 in Hong Kong stands at a relatively high level. It is not solely for the Government (or the WSD) to deal with the potentially global crisis and push forward a number of initiatives on water conservation. Every one in Hong Kong and business community shall also share the global responsibility to use the precious water resources wisely and in a sustainable manner. Although Hong Kong enjoys a reliable supply of fresh water and the forecast water demand can be met by the current water supply arrangement, we shall be looking forward to better prepare Hong Kong for uncertainties and to enhance Hong Kong s role as a good partner to other municipalities in the Pearl River Delta in promoting sustainable use of water in the light of rapid growth of water demand in the region. In this connection, the Government promulgated a Total Water Management (TWM) strategy in Hong Kong s potable water consumption per capita is about 130 litres/head/day in 2012, as compared to a suggested world average of about 170 litres/head/day. 1

343 2. TOTAL WATER MANAGEMENT TWM is a modern concept for managing water resources in all aspects. It seeks to achieve an optimal balance between water demand and water supply in order to ensure sustainable use of water resources. The TWM strategy aims to manage the demand and supply in an integrated, multi-sectoral and sustainable manner. The strategy puts emphasis on containing growth of water demand through conservation by water demand management and strengthening water supply management. For effective water demand management, we have to enhance public education on water conservation, to promote the use of water saving devices, to enhance water leakage control through the programme to replace and rehabilitate aged water mains and to apply new technology to improve pressure management and detection of leakage, and to extend the use of seawater for toilet flushing. In order to strengthen water supply management, protection to water resources shall be strengthened. Besides, we have to consider water reclamation (including re-use of grey water and rainwater harvesting) and develop the option of seawater desalination. 3. WATER EFFICIENCY LABELLING SCHEME (WELS) 3.1 WHY WELS? To echo the Government s advocacy on water conservation, the WSD has taken proactive steps in promoting the use of water saving devices through the development of a voluntary Water Efficiency Labelling Scheme (WELS). The scheme has been implementing in phases for different groups of plumbing fixtures and water-consuming appliances to provide consumers with information on the amount of water consumption and thus water efficiency grading of plumbing fixtures and water-consuming appliances. It also helps consumers select water efficient plumbing fixtures and water-consuming appliances. Besides. WELS could promote public awareness on water conservation and efficiency issues and achieve actual water savings. Using water saving devices is an effective way to conserve water by reducing the water demand as compared with conventional plumbing fixtures and appliances. Overseas studies show that domestic demand can be reduced by 25% to 37% with the use of water saving devices. WELS can facilitate consumers to select water efficient products. Consumers are able to compare the plumbing fixtures and appliances that meet up to the standards for water efficiency by simply reading the WELS labels affixed to the products and their packages. As such, if WELS is well received, its influence on consumers preference will be largely enhanced and thereby, the market penetration of water saving devices will expand. Following the gradual market migration to water saving devices, considerable amount of water can be saved. 3.2 DEVELOPMENT In the course of WELS development for each of the plumbing fixtures and water-consuming appliances, relevant stakeholders including trade associations of licensed plumbers, 2

344 importers and hotel operators, testing laboratories and chambers of commence, learned societies, relevant government departments and quasi-government organizations, have been consulted in two stages on the draft framework and draft scheme document of WELS. The draft framework outlines the implementation schedule, labelling system, performance requirements, testing laboratory requirements, participation process, compliance monitoring and inspection. For the draft scheme document, it gives a detailed description of WELS on respective water saving device and requirements for registering products under WELS. In order to widen the consultation to cover all interested parties, the draft framework and draft scheme document of WELS have been uploaded to the Business Consultation e-platform of the Economic Analysis and Business Facilitation Unit to attract public comments or to facilitate public consultation. Concurrently, a Business Impact Assessment on WELS has been conducted to identify the market coverage and benefits to the business and to make recommendations on the operation of WELS. On the other hand, WELS falls under the scope of the World Trade Organisation s (WTO s) Technical Barriers to Trade (TBT) Agreement that governs the labelling requirements applicable to a product. With a view to meeting the relevant provisions of the TBT Agreement on the preparation, adoption and application of standards, and conformity assessment procedures, the finalised scheme document has been submitted to the WTO TBT Committee for clearance that WELS has no technical barriers to trade. The WSD also organised promotion seminars to trade members upon launching of each scheme so as to promote and explain details, as well as address the queries, of the scheme. The WSD has prepared a comprehensive publicity and promotional plan to arouse public awareness on the benefits of using water saving devices and the importance of water conservation. 3.3 IMPLEMENTATION There exists numerous types of plumbing fixtures and water-consuming appliances on the market. However, those products could not be implemented simultaneously due to limited resources. As such, launching of products under WELS has been implemented progressively and in stages. In selecting and prioritizing the products for inclusion in WELS, the WSD has made reference to relevant overseas studies. The highest priority should be given to those representing a significant share of household water use and those delivering maximum water savings. At the same time, considerations should be given to the market potential, administrative feasibility and cost effectiveness. Based on the water consumption and potential saving criteria, the WSD has launched various products showers for bathing (in September 2009), water taps (in September 2010), washing machines (in March 2011) and urinal equipment (in March 2012). With a view to considering possible revisions to WELS on the existing products, a review exercise has been/will be carried out by the WSD two years after initial launching of each registered product and thereafter at five years interval to review the market development of the plumbing fixture and appliance, technology advancement, market response, testing standards, etc. The scheme on respective WELS product only covers new products imported to or manufactured in Hong Kong but does not cover second-hand products, products already in existing use, under trans-shipment or manufactured for export, etc. 3

345 3.4 WATER EFFICIENCY GRADE It is important to decide in the first place whether WELS in Hong Kong should be operated under a Grading Type or a Recognition Type labeling system. This will be based on the performance of the plumbing fixture and appliance available in Hong Kong. For significantly diversified performance, a Grading Type labeling system would be adopted to distinguish such diversification, while a Recognition Type labeling system would be more suitable for products of relatively uniform performance. In view of the significantly diversified performance of the plumbing fixtures and water-consuming appliances in the market of Hong Kong, it is more suitable to operate WELS on a Grading Type labelling system in this territory. In defining the water efficiency grades, accredited testing laboratories have been employed to conduct the performance tests for the products, which shall comply with the test standards and requirements stipulated by the WSD, from which the products are graded according to their nominal flow rates / water consumptions / minimum water flush volumes. Summaries of gradings for the current WELS products are shown in Appendix A. Grade 1 products are the most water-efficient whilst those of Grade 4 being the least. Products with better water efficiency save more water. For instance, a Grade 1 shower for bathing may approximately save at least 40% of water as compared with a Grade 4 counterpart. As such, it is easier and more apparent for consumers to choose water efficient products and know how much water they can save from using such products. Appendix B illustrates the potential savings based on water-consuming appliances categories and their grading. 3.5 WELS LABELS Registered product under WELS is affixed with a water efficiency label that informs consumers of its level of water consumption and water efficiency, thus facilitating their making of purchase decisions. There are two versions of the water efficiency label the full and the simplified versions where it is compulsory to affix full version labels whilst the affixation of simplified version labels is optional. The labels are illustrated in Figure A and Figure B: Water droplets: the fewer droplets, the more water efficient. The water consumption figure based on tests carried out by a recognized laboratory. The water efficiency grading (1 to 4): different grades are shown with different colours. Grade 1 is the most water efficient (i.e. the most water saving) Figure A: Full Version WELS Label 4

346 Figure B: Simplified Version WELS Labels 4. USE OF WATER EFFICIENT (SAVING) DEVICES IN GOVERNMENT BUILDINGS AND SCHOOLS With a view to promoting the use of water saving devices and to match with the implementation of the policy on green government buildings, the Government has taken a leading role to install water efficient devices for government projects and buildings. In this connection, the WSD has commenced a project to retrofit plumbing appurtenances with water saving devices in existing government buildings and schools, in phases. The WSD has conducted a site survey that revealed the no. of government buildings and schools (about 8,500) as well as the amount of plumbing appurtenances for retrofitting (about 250,000). In view of the vast number of concerned venues, the WSD has carried out a study for prioritisation of the government buildings and schools, which screened out venues not suitable for the retrofitting works and at the same time, prioritised the eligible venues through a score allocation system. The system has taken into account the venue type, population factor, whether the venue uses fresh water for flushing and the year in service. The pilot project (i.e. Phase 1 of the project) commenced in June 2009 and was completed in August 2011, in which about 32,000 water saving devices (low flow showers, dual flush cisterns, sensor type urinals and low flow sensor type water taps) have been installed in 460 venues. At the same time, water consumptions of those retrofitted venues have been continuously monitored to collect data for collation and analysis. Preliminary analysis revealed potential annual savings of around 20% and 26% in the quantities of fresh water and flushing water, from which about 450,000 kilowatt-hours of energy consumption for treatment and delivery of fresh water and flushing water can be reduced and preventing about 300 tonnes of carbon dioxide in accumulation annually. Phase 2 of the retrofitting project have commenced since April 2012 for completion by December 2013, in which about 20,600 plumbing appurtenances will be retrofitted in 138 venues. It is anticipated that similar amount of saving of fresh water, salt water and energy consumption would be achieved. Other government departments also promoted the use of water saving devices - Architectural Services Department has been installing water saving devices in new government facilities and refurbishment projects as far as practicable, whilst Housing Department has been installing water saving devices in new housing estates. 5

347 5. WAY FORWARD Through the provision of water efficiency information, WELS has provided a framework for promoting the use of efficient water saving devices thus reducing water consumption. In Hong Kong, not only have consumers been advised to pay attention to WELS labels in choosing water saving devices, but the WSD has also encouraged manufacturers, importers and other related parties to participate in the scheme. At the same time, the WSD is extending the coverage of the scheme by engaging further studies to include more products, such as flow controllers. Whilst studies are underway to determine the feasibility of extending the coverage of WELS to other water-consuming appliances, the WSD has been conducting review on the existing schemes. In the review, factors such as market development, technology advancement, operating procedures and feedbacks from the trades have been taken into account. We aim to continue developing WELS for the market of water-consuming appliances to take up more water efficient products. As far as water conservation is concerned, the continual support and participation of the public and business communities are indispensable. Apart from organising various publicity campaigns, the WSD will continue to review and monitor the existing strategy and explore new ways to strengthen the initiatives under the TWM strategy. 6

348 REFERENCES Books / Booklet The Government of HKSAR. Total Water Management in Hong Kong Towards Sustainable Use of Water Resources. Hong Kong: Government Logistics Department, Reports and Papers / Articles and Journals The Water Supplies Department, HKSAR. Scheme Document for the Voluntary Water Efficiency Labelling Scheme (WELS) on Showers for Bathing. Dec update. The Water Supplies Department, HKSAR. Scheme Document for the Voluntary Water Efficiency Labelling Scheme (WELS) on Water Taps. Dec update. The Water Supplies Department, HKSAR. Scheme Document for the Voluntary Water Efficiency Labelling Scheme (WELS) on Washing Machines. Mar The Water Supplies Department, HKSAR. Scheme Document for the Voluntary Water Efficiency Labelling Scheme (WELS) on Urinal Equipment. Mar The Water Supplies Department, HKSAR. Brief for the Provision of Consultancy Services for Development and Implementation of the Voluntary Water Efficiency Labelling Scheme on Flow Controllers. Jun The Water Supplies Department, HKSAR. Resources Planning Report No. 2/2011 Retrofitting Plumbing Appurtenance with Water Saving Devices in Government Buildings and Schools. Jun Peart, Mervyn R. Water supply and the development of Hong Kong. Dec The Internet and Electronic Resources The Water Supplies Department, HKSAR. < assessed 25 May Tips for Saving Water, GovHK. < assessed 10 May Rudolphy, Katy. Water Resources An Overview of Water Resouces and the Uses of Water on Earth. < assessed 20 Jun China Water Risk (CWR). The Future of Hong Kong Water Interview with Bobby Ng (Assistant Director/Development, Water Supplies Department) on September 11, 2012 < assessed 17 Jun

349 THE BUILDINGS ENERGY EFFICIENCY FUNDING SCHEMES A PRELIMINARY TECHNICAL REVIEW Mr Szeto Wing-sum and Mr Raymond Y. F. Tong 1 Electrical and Mechanical Services Department, Government of the Hong Kong SAR 1 Corresponding Author Address: Electrical and Mechanical Services Department, Project Division, 3 Kai Shing Street, Kowloon, Hong Kong. raymondtong@emsd.gov.hk, Tel: (852) , Fax: (852)

350 THE BUILDINGS ENERGY EFFICIENCY FUNDING SCHEMES A PRELIMINARY TECHNICAL REVIEW ABSTRACT The Government has committed HK$450 million to launch the Buildings Energy Efficiency Funding Schemes (BEEFS) in April 2009 to subsidize building owners for conducting energy-cum carbon audits (ECA) and energy efficiency projects (EEP). The Schemes were closed after three years in April The paper aims to present the results of funding applications, and the observations and findings obtained so far in the course of processing the applications. 1. INTRODUCTION The Government is committed to promote a low carbon economy an economy based on low energy consumption and low pollution, and to work closely with the international community in tackling the challenges of climate change. As proposed in the Policy Address and approved by the Environment and Conservation Fund (ECF) Committee 2, HK$450 million has been reserved under the ECF to launch the Buildings Energy Efficiency Funding Schemes (BEEFS) to subsidize building owners for conducting energy-cum carbon audits (ECA) and energy efficiency projects (EEP). The Schemes are administered by the Environment Bureau (ENB) who engages the Electrical and Mechanical Services Trading Fund (EMSTF) to set up the BEEFS Office in EMSTF to process the funding applications. The ECF Committee also established the Energy Conservation Projects Vetting Subcommittee (ECPVSC) to approve the BEEFS applications. The Schemes were opened for application in April 2009, and lasted for three years or until the allocated funds were fully utilized, whichever was the earlier. Application for the Schemes was closed in April 2012 as scheduled. Under the Schemes, eligible applicants are (i) Owners Corporations registered under the Building Management Ordinance (Cap. 344), (ii) owners organizations or (iii) residents organizations. A Guide to Application (Guide) for ECA and EEP has been published to provide guidance and describe the requirements concerning application of the Schemes and other details for applicants to comply in the course of the proposed projects. 2. SCOPE AND MAJOR REQUIREMENTS FOR ENERGY-CUM-CARBON AUDIT (ECA) The scope of ECA is to systematically review the use of energy and quantify the greenhouse gas (GHG) emissions associated with the building, and to identify opportunities for enhancements of energy efficiency and conservation and reductions in the level of GHG emissions arising from building operations. The scheme will cover energy-cum-carbon audits to be carried out in communal areas of residential, 2 ECF Committee was established under the Environment and Conservation Fund Ordinance in 1994 to vet and approve applications from local non-profit making organizations seeking funding support from the ECF to undertake educational, research and other projects and activities in relation to environmental and conservation matters. 2

351 commercial, industrial buildings or composite buildings comprising any two of these three types of establishments MAJOR REQUIREMENTS FOR ECA According to the Guide, funds would be granted on a matching basis. A limit of 50% of the approved total actual expenditure spent on the audit and subsequent reporting would be reimbursed subject to a maximum of HK$150,000 per building per application. A Qualified Service Provider (QSP) should be employed to carry out the audit, certify and submit subsequent reports. For procurement of services related to an approved ECA, the applicant should observe the Code of Practice on Procurement of Supplies, Goods & Services issued under the Building Management Ordinance (Cap. 344) as guidance, especially in obtaining tender from necessary number of suppliers and in awarding to supplier with the lowest bid. Any proposed ECA which has been started i.e. contract awarded or signed before approval by the ECPVSC is given would not be accepted. The ECA should be carried out according to the latest edition of the Guidelines to Account for and Report on Greenhouse Gas (GHG) Emissions and Removals for Buildings (Commercial, Residential or Institutional purposes) in Hong Kong and Guidelines on Energy Audit issued by the Government. Besides conducting an energy-cum-carbon audit, successful applicants are also required to submit a progress report every year for 3 immediate subsequent years after the reporting year of the 1st audit. Progress reports to be submitted should include progress of major follow up actions taken to improve GHG emission and energy efficiency and conservation of the building, and any improvements observed. 3. SCOPE AND MAJOR REQUIREMENTS FOR ENERGY EFFICIENCY PROJECT (EEP) The scope of EEP is to carry out alteration, addition or improvement works to upgrade the energy efficiency performance of building services installations for communal use in residential, commercial, industrial buildings or composite buildings comprising any two of these three types. Building services installations covered in the EEP include lighting, air-conditioning, lift and escalator and electrical installations MAJOR REQUIREMENTS FOR EEP Similar to ECA, funds for EEP would be granted on a matching basis. A limit of 50% of the approved total actual expenditure spent on the energy efficiency project would be reimbursed subject to a maximum of HK$500,000 per building per application. A QSP should be employed to oversee the technical aspect of the project and to certify and measure the performance of the installation after it has been completed. Similar to the ECA, the Code of Practice on Procurement of Supplies, Goods & Services should be observed for procurement of services related to an approved EEP. Any proposed EEP which has been started before approval by the ECPVSC is given would not be accepted. 3

352 The building services installations covered in the project should comply with or be more energy-efficient than the relevant energy efficiency standards stipulated in the Building Energy Codes issued by the Electrical and Mechanical Services Department (EMSD) upon completion of the project. The approved project should commence within 12 months and be completed within 24 months after its approval. A completion report in a prescribed format should be submitted within 6 months upon completion of the project to review the effectiveness of the project. 4. VETTING OF APPLICATIONS Table 1 shows the number of applications received in the three years. Table 1: Total BEEFS Applications Received ECA EEP ECA EEP ECA EEP ECA EEP Nos Upon the closing of the Schemes, a total of 2,004 applications (233 ECA and 1,771 EEP) had been received and approx. 88% of them were EEP applications. The figures also revealed there was a change of preference from ECA to EEP after The number of ECA applications received dropped from a monthly average of 22 in 2009 to less than one in Once an application was received, the BEEFS Office would normally assign a project officer to handle the application until its completion for effective communication with the applicant. The project officer would verify the eligibility of the applicant, clarify or seek supplementary information and vet the submission according to the vetting criteria published in the Guide. Site inspections and measurements would be also conducted to assess the existing and proposed installations and the associated budget. When the application met the necessary requirements, recommendation would be made to the ECPVSC for funding approval or endorsement. 5. RESULT ANALYSIS OF APPLICATIONS Among the 2,004 applications received, 222 applications had been withdrawn by applicants, with some of them withdrawn after project approval. There were various reasons for the withdrawal, including a change of committee members who decided not to proceed, a change of priority within the buildings, not supported by owners in the General Meeting, etc. A further 383 applications had been rejected due to one of the following reasons: The applicant was not eligible i.e. not a residential, commercial or industrial building; applicant is neither an Owners corporation, owners organization nor a residents organization; or Inadequate information for assessment despite repeated reminders; or The proposed project in the application had been started (i.e. contract awarded or confirmed) before the application was approved by the ECPVSC. Additionally, 284 applications could not be processed because the allocated funds had been fully committed, leaving a total of 1,115 applications approved (103 no. of ECA and 1,012 no. of EEP). 4

353 Table 2: Types of Categories of EEP Applications Categories Apr 2012 Lighting % % % % Lift & Escalator % 82 32% % 91 34% Air-conditioning 26 3% 11 4% 14 4% 18 7% Electrical 18 2% 5 2% 12 3% 14 5% Multi-installation % 20 8% 21 5% 45 17% Total (1,771): % % % % Among the 2,004 applications received, there were 1,771 EEP applications. Table 2 shows the categories of EEP applications received over the years. At the beginning when the Schemes were launched, most applications were concerning lighting installations. That was probably due to its low initial cost and short payback period. In the first year, only 14% of the applications involved lift & escalator installations. In the following years, it was noted that the applications for lift & escalator have steadily increased until it almost levelled with the number of lighting applications. Though, overall speaking, lighting projects remained on the top of the proposed project list. 6. ENERGY SAVING AND OBSERVATIONS FROM EEP RESULTS At present, about 300 applicants have notified the BEEFS Office of their completion of the approved projects and around 187 of them have been verified so far. Table 3 summarizes some of the observations. Categories Table 3: Information Obtained from Completion Reports No. of projects Est. Energy Saved (kwh per annum) Original Funded Amount (million HK$) Calculated Saving (kwh per annum) Upon Completion Saving (%) Est. Payback (Yr) Lighting ,219, ,508, % 3.2 Airconditioning 4 488, , % 4.4 Lift & Escalator 20 1,810, ,737, % 33.7 Electrical 6 1,574, , % 3.1 Multiinstallation 18 4,666, ,749, % 4.0 Total: ,759, ,511, % 5.9 In general, about 20% of saving could be achieved by replacement of more energy efficient equipment, among which the energy saving from lift & escalator installations was the highest. It was noted that apart from replacing with energy efficient motors and controls in their lifts, many building owners also implemented additional energy saving measures such as reducing lift operation during non-peak hours or closing down some of them in the mid-nights. Such measures also provided extra saving and boosted up the extent of saving in this category. However, the investment for lift upgrading was also the highest resulting in the longest payback period. The overall 5

354 average shows that the EEP projects should achieve a payback period of around 6 years. If lift replacement projects were excluded, the payback period could be reduced to around 3 years. As indicated earlier, lift and escalator applications increased steadily over the years despite higher cost and longer payback period. It was observed that in this category the applicants preference focused more on latest lift safety requirements, its reliability and passenger comfort. Their main purpose in applying for the funds was to improve these features and safety of their old lifts rather than energy efficiency. Since the Schemes only subsidized energy saving items, the actual investment by the applicants on their lift upgrading projects were much higher. The cost effectiveness of the different categories of replacement projects is reflected in their payback period. Lighting and electrical categories are the most cost effective ones while lift and escalator projects are the least. It is rather unexpected to note the cost effectiveness of electrical projects which mainly comprised water pumps, variable frequency converters and motion / proximity sensors is even more cost effective than the lighting category. In view of the very limited sample size of the electrical category at this stage, the results would be monitored and further reviewed when more data is available. 7. BEEFS CHALLENGES When the Schemes were first launched, there was concern that multiple buildings might have advantage over single buildings as multiple buildings often had the support of sizeable property management companies to look after their applications and coordinate with the BEEFS Office, whereas single buildings were often old buildings and did not have similar resources to handle the applications. Table 4: Total BEEFS Applications Received According to Building Types ECA EEP Total Single Buildings % % % Multiple Buildings % % 1,061 53% Total : % 1, % 2, % To address this, the BEEFS Office had paid special attention in promoting the Schemes in districts with substantial number of single buildings, such as the Central & Western and the Wanchai districts, alongside with the local community organizations to assist owners of single buildings. With that effort, it was pleased to note that the ratio of applications from single to multiple buildings was roughly the same as shown in Table 4. In some of the EEP applications with installations located at a rather high level, mostly lighting installations, special arrangements with the applicants or the property management companies were required to verify the situation and quantities of these installations. In cases of large housing development where the quantities of lighting installations proposed to be replaced were substantial, there were often repeated discrepancies in the actual quantities and even types of lighting installations in the applicants project proposals. The BEEFS Office would need to carry out repeated inspections and site verifications with the applicants, thereby prolonging the vetting process of the EEP applications. There was also concern in assessing the appropriate amount of funds in each application. Comprehensive market research had been conducted among suppliers 6

355 and contractors to establish the reference pricing for different types of energy efficient equipment. Price schedules in past contracts were also used as reference. These data were then used to assess the project budget before recommending a reasonable amount of funds for approval by the ECPVSC. To keep up with market changes, much effort has been made in collecting and timely updating those reference prices to avoid substantial deviation of the approved project budget from the actual tender price. While technological advancement allows lighting to consume much less energy, this has resulted in over-illumination in some EEP projects, leading to complaints from some building owners/residents of over provision and waste of energy. However, there were also counter arguments in those cases that residents need better illumination in communal areas to feel safe. While it was the role of the QSP engaged by the applicants to design the lighting installations, the BEEFS Office was often drawn into those cases to mediate and liaise with the applicants to suitably replace/modify the lighting installations or circuits or adopt different modes of operation for different situations to address the residents concerns. All those issues have caused inevitable delays in the completion of the concerned EEP projects. 8. SUCCESS OF BEEFS It was probably due to the successful public education by the Government and the engineering trade on the common and proven types of energy efficient installations, e.g. T5 lights, LED lights, high efficient motors, VVVF lift controls, etc. that most applicants had chosen to go for EEP direct instead of first conducting an ECA. This was reflected in the change in ratio ECA/EEP applications received over the 3-year application period. The Schemes have also enhanced business opportunity especially for the lighting manufacturers in launching new LED products which had become more popular nowadays with more competitive prices. Besides manufacturers, the Schemes have also been successful in motivating other sectors to gear up for the opportunities i.e. provision of training courses on energy and carbon audits, equipping property management agents with energy efficiency knowledge and skills, etc. With the amount of projects approved, the Schemes were estimated to have created jobs of about 70,000 man-month. 9. CONCLUSIONS As most of the approved projects are still underway, the results presented in this paper could only be considered as preliminary observations. Upon the completion of all approved projects, it is envisaged that saving of 180 million kwh per year, which is equivalent to a reduction of carbon dioxide emissions by 126,000 tonnes, could be achieved. From among the 1,115 projects approved under the Schemes, over 6,400 buildings were involved, and the applicants were from a broad sector of the communities. It is certain that the message on the benefits of building energy efficiency has been widely publicized and the intended objectives of promoting building owners awareness of the benefits of building energy efficiency and encouraging them to take concrete actions to seek improvement have been achieved. 7

356 Formulating social indicators of revitalizing historic buildings in urban renewal: towards a research agenda Esther, H.K. Yung and Edwin, H.W. Chan Department of Building and Real Estate The Hong Kong Polytechnic University Abstract Urban renewal is often beset with social problems such as destruction of existing social networks, expulsion of vulnerable groups and adverse impacts on living environments. Numerous historic buildings are located in the old dilapidated areas undergoing large scale urban renewal. Although conservation of historic buildings is increasingly recognized to contribute to social well-being and sustainability in the urban city, the tension between heritage conservation and redevelopment is always a controversial issue. In this context, it urgently needs a robust evaluation framework for the impact of revitalization of historic buildings in urban renewal districts. This paper proposes a research to explore the possible social impacts of revitalizing historic buildings in urban renewal on the community life. With intensive literature review, a list of social impacts with the elaborated factors was identified. Case studies will be further undertaken to validate the list of social impacts. In addition, the corresponding indicators will be developed for the refined list of social impacts. The indicators will be formulated using a public participatory approach of the general public. The entire theoretical framework and the social indicators aim to assist the general public in assessing the social sustainability of the revitalization of historic buildings on the renewed districts. In particularly, it helps to evaluate the tangible and intangible, short-term and long-term, positive and negative impacts on the community. Keywords: social indicators, revitalization, historic buildings, urban renewal, sustainability Introduction There is an ongoing debate on whether conservation and redevelopment can be complementary (Larkham, 1996, Delafons, 1997). It is increasingly recognised that the two can coexist and there is a great potential for conservation-led regeneration worldwide (Powell, 1992; Yeoh and Huang, 1996; English Heritage, 2005; Amit-Cohen, 2005). The mobilization of historical environments has become a staple element of post-industrial urban renewal strategies and generating business opportunities (Kearns and Philo, 1993, Swensen, 2012). Urban renewal can be seen as a strategy focusing on the physical improvement of the deteriorated and obsolete built environment. The historic building(s) is not only conserved for its associated historical value and architectural value, but also for its rich social values to the society as a whole. It has the potential to enhance the place-making character of urban area (Swensen, 2012). However, the social impacts on the community are often overlooked. Social issues include conflicts involving the cultural role of heritage and loss of social continuity and community neighborhood, property speculation, loss of sense of place, urban sprawl, gentrification and social exclusion (Pendlebury et al., 2004; Chan and Lee, 2008; UNESCO, 2004, 2005; UN-HABITAT, 2008, Yung and Chan, 2012a). In particular, exclusion of community participation also leads to a lot of social issues in heritage conservation (Yung and Chan, 2011). As there is a growing tendency for giving a new use for the historic buildings, the uniqueness and local characteristics of each townscape which interact with the historic buildings have often been overlooked. Whether and how the new use of the historic building has been implemented and integrated with the renewed urban setting is a vital challenge (Swensen, 2012, Yung and Chan, 2012b). Urban setting characterized by continuous change (Jones, 2007) has even made the historic building 1

357 more difficult to integrate the surrounding context. As in many cities, conservation of single buildings rather than surrounding neighbourhood and district has often been taken place (Swensen, 2012). This further creates challenges to defining meanings for the historic buildings in an area undergoing a transformation. This in turn, usually leads to social issues. Historic buildings are not only referred to those listed buildings or monuments of international or national significance, but also those containing the familiar and cherished local scene (Delafons 1997; Lamei 2005) in the local community. Inevitably, historic buildings situating in old urban areas are facing demolition threat, particularly in cities with immense redevelopment pressure. In Hong Kong, heritage conservation regime has not been in urban renewal agenda until recently, in particular, after the Star Ferry and Queens Pier Conservation controversies. Some argue that urban renewal has been perceived as just another developer (Lam, 2009, Lai, 2010). As different from many other countries, urban renewal aims to revitalise a declining or depressed area or economy, a property-led redevelopment strategy has been adopted in vibrant neighbourhoods, full of local economic activities, social capital and unique culture and histories and at convenient locations (Ng, 2009). As such, historic buildings situated in the urban renewal districts are likely to be compromised for economic concern and profit making. The social value is often at best, not fully utilized, and at worst, sacrificed and even neglected. As a result, it creates many adverse social impacts to the local community. Thus, this paper presents a list of critical factors to assess the social impacts of revitalizing historic buildings in urban renewal, using Hong Kong as a case study of dense urban city facing immense redevelopment pressure and favor in economic growth. The initial list of critical factors are concurrently identified through literature review. The list of critical factors is scrutinized from the controversial social issues of revitalizing historic buildings and the key roles and benefits it raise in urban renewal. Different critical factors would be relevant to projects with different characteristics, including the local community, scale of the historic building site, future use of the building, and (re)development in the local vicinity, etc. Therefore, the social impacts identified will form a generic theoretical framework, elaborated with the corresponding qualitative evaluation questions. The framework represents a template for evaluating a wider range of revitalization of historic buildings in urban renewal districts. The study will further verify and refine the list through in-depth interviews with a panel of experts. The framework developed will be further tested and analyzed in case studies which will be conducted. The final stage of the study includes developing corresponding social indicators adopting the participatory approach of the general public. The rest of this paper is organised as follows. In the next section, we provide an overview of the urban renewal regime and the evolving trend in recent years. We also provide a concise review of the social role of revitalization of historic buildings in urban renewal districts. Then, we next turn to provide the context for the revitalization of historic buildings in urban renewal in Hong Kong. We then present the methodology and the initial list of social impacts of revitalization of historic buildings in urban renewal. Finally, we came to the initial results and the way forward for developing the robust theoretical framework and the corresponding indicators in assessing the social impacts of heritage conservation on urban renewal. 2

358 Urban renewal Urban renewal is a process involving physical change, or change in the intensity of use of land and buildings resulting from the economic and social forces imposed on the urban areas (Couch, 1990). Healey et al. (1992, p.3) describe renewal in action as '[r]ebuilding the city, clearing away obsolete buildings and vacant sites, and producing new building forms and designs'. It is increasingly common in modern societies to improve urban quality of life (Goodman and Monti, 1999). Some stress that urban renewal involves the improvement of environmental quality, and resettlement of households (Planning and Lands Bureau, 2001). Priemus (2004) highlighted that urban renewal did not simply involve brick and mortar and it involves a process combining physical, social and economic considerations. In cities worldwide, urban renewal has become increasingly important strategies in urban planning and development. In addition to demolition and reconstruction of decayed and obsolete buildings to create better living environment, urban renewal also emphasizes conservation and revitalization (Steel and Slayton, 1965). Revitalization is defined as The process through which the mismatch between the services offered by the fabric of the historic quarters and the contemporary needs can be reconciled (Tiesdell et al., 1996). Urban renewal which has disregarded the neighborhood, heritages and natural environment, ultimately will deteriorate the quality of life of the citizens (Lee, 2003). As such, a property-led redevelopment model which adopts the bulldozers approach has increasingly been replaced by the more sustainable, conservation-led redevelopment model in the last two decades (Feng and Wang, 2009; Pendlebury, 2002). It is evident that conservation-led redevelopment encourages private-sector investment and partnership (English Heritage, 2000, Yang and Chang, 2007). It is also increasingly recognized that conservation of historic buildings in urban renewal can embrace the social and cultural benefits (Chan and Lee, 2008). The social benefits of revitalization of historic buildings in urban renewal As stated in the 1987 Washington Charter, [urban] conservation should be an integral part of coherent policies of economic and social development and of urban and regional planning at every level (ICOMOS, 1987, p. 1). Previous research suggests that revitalization of historic buildings can potentially provide the following social benefits. Sense of place It refers to a feeling of belonging and attachment, and importance that the visitors, residents and workers have on the place. It is stated that sense of place arises from a multi-dimensional experience including, views, sounds, scents, textures, tastes, movement, individual impression, etc. (White, 1999). Stubbs (2004) proposes sense of place as a social indicator of historic sustainability and construction of new place attachment. It is clearly recognised that people enjoy living in historic places because there is often greater community cohesion (English Heritage, 2005). On the other hand, the everyday experience of the people of the place may contain negative feelings of toleration or frustration (Lynch, 1972). Collective memory It is a feeling that is shared, passed on and also constructed by a group or modern 3

359 society related to an urban space (Boyer,1996). Heritage is used as a form of collective memory, a social construct shaped by the political, economic and social concerns of the present (Halbwachs, 1980). Collective memory relates to both the tangible physical evidence of the past (Barthel, 1996) and the intangible evidence /symbols for people to get in touch with the past including the character defining elements. In the context of urban renewal, it can relates to the everyday lives, communications and meanings attached to the district before the transformation (Assmann, 1995). Previous work also links collective memory with a deep bereavement when people saw or heard that heritage building was torn down (Fried, 1963). Cultural identity It can be defined as some common means/ ground of identifying with each other associated with the place in different time context. It helps the understanding of the individual as a coherent group of various characteristics including location, history, aesthetics, religious beliefs, etc. (Ashworth, Graham and Tunbridge, 2007; Guibernau, 1996) Local characteristics and uniqueness Cultural heritage has a role to play for developing the place-specific character of urban regions (Swensen, 2012). Conservation and revitalization of historic buildings should improve the physical condition of the environment while maintaining and enhancing local life and culture and the uniqueness of the place (Strange and Whitney, 2003). It is claimed that facilitating diversity in various human activities can boost the quality of environments and human life (Zukin, 1998). People s desire for diversity has been increasingly visible in the proliferation of lifestyles associated with identity building which enhances the streetscape and townscape of the city s urban fabric (Cullen, 1961). Educating present and future generations Historic buildings can educate present and future generations on the history of the people, the place and the events connected with the district (English Heritage, 1997; Atkins and IFA, 2004). It is also very important that appropriate interpretation should enhance understanding and enjoyment of the historic place (Australia ICOMOS, 1999). City liveability It refers to the extent to which that environment supports individual and collective needs (Stevens, 2009). It is the part that the physical environment plays in day-to-day life and its contribution to perceptions of satisfaction, safety, sense of place and community and community stability (Dempsey, 2008). It is also raised that whether social well-being and quality of life, has been enhanced by implementing polices that stress city livability in urban regeneration projects in the UK (Colantonio and Dixon, 2011). Cultural diversity It is recognized as Common heritage of humanity (UNESCO, 2001) and equality and valuing different cultural experiences, whether they are due to ethnic identities, social or economic situations (English Heritage, 2000, p.15). The historic environment contributes to quality of life and enriches people s understanding of the 4

360 diversity and changing nature of their community (English Heritage, 2005). Community interaction and social cohesion It is recognized that a heritage resource contributes to enhancing the contemporary social interaction in the community (Feilden and Jokilehto, 1998). Research also states that social networks and interaction can enhance mutual understanding, trust, sharing and increase in social capital (Coleman, 1988, Putman, 1995). However, gentrification often occurred in urban regeneration process is increasingly threatening the social cohesion of the local community (UNESCO, 2004). Illustrate the economic and scientific development took place in the district Historic buildings can show evidence of economic, engineering, technological or scientific advances by which specific industries have contributed significantly to the development of the city. Accessibility of use Accessibility refers to how easily people can reach services and facilities at reasonable cost, in reasonable time and with reasonable ease (Social Exclusion Unit, 2001, p.1). Affordability in terms of ease of access and/or entry fees can be a prerequisite for equal access to historic sites, without encroaching on people s rights to use, visit and appreciate the place. Social inclusion Historic environment contributes to improving the physical environment which is one of the objectives of a social inclusion policy (DCMS, 2002). It can be achieved by broadening access and education, acknowledging cultural diversity and multiculturalism and developing partnerships and community involvement (Pendlebury et al., 2004). Developing skills in heritage restoration and related activities The revitalization of historic buildings can offer people the possibility of developing technical and/or social skills through work experience as volunteers or paid workers in heritage related activities (Atkins and IFA, 2004), such as the restoration of historic buildings and the provision of guided tours for visitors. Public involvement opportunity Active participation in the historic environment can positively affect the sense of belonging that can help people develop social networks with others, increase their pride in and understanding of the local area, identify their common interests, aspirations, goals and courses of action and improve their self-efficacy (Bramley and Power, 2009; Heritage Lottery Fund, 2009; Yung and Chan, 2011). In particular, the local population should be encouraged to take part in every phase of the revitalization process (ICOMOS, 1987). Revitalization of historic buildings regarding social aspects in urban renewal in Hong Kong The role of revitalizing historic buildings has been mainly rest upon the Urban Renewal Authority (URA) for the privately owned buildings, and the Development Bureau for the publicly owned buildings in the last two to three decades. In Hong 5

361 Kong, the main conservation strategy adopted in urban renewal district has been to bundle small scale individual historic buildings with large scale redevelopment. Although the idea of preserving local characteristics and social networks has been increasingly advocated in urban renewal regime (Development Bureau, 2011), many traditional trades and businesses had always been disappearing from the streetscape in the past history of Hong Kong. The commercial redevelopment which claims to subsidize the revitalization and reuse of the historic buildings has often destroyed the local characteristics of the district. Displacing the existing local inhabitants creates discontinuity of neighbourhood and the social network (Lai, 2010). The Urban renewal authority (URA) was established in 2001 to assist the Hong Kong government in regenerating the decayed urban environment (Planning and Lands Bureau, 2001). URA is tasked to undertake redevelopment and rehabilitation as its core business under the Four R s Strategy, including Redevelopment, Rehabilitation, heritage preservation and Revitalization (URA, 2011). A major review of the Urban Renewal strategy in Hong Kong, has been carried out to resolve the growing problems associated with urban regeneration since The key reasons behind the review include the increasing demands from the public for retention of local characteristics and communities, particularly, the preservation of sites and structures of historical, cultural and/or architectural interest, and preserving the social networks of the local communities. The final Urban Renewal Strategy was finalised in 2011, initiates a social impact assessment for all the renewal projects, to assess a list of socio-demographics factors, local and cultural characteristics and social needs of the people affected by the proposed project. However, the impact of any preservation and revitalization of historic buildings has yet to be thoroughly investigated. The URA has been undertaking 10 projects for the revitalization of historic buildings in the old districts, in which some are still in progress. The first completed heritage project was a Shop-house clusters, which has been criticized on its focus to achieve economic objectives and has overlooked social aspects. The Board of the Urban Renewal Authority (URA) in 2008 decided to adopt a conservation-led redevelopment approach for the controversial case of the Wing Lee Street project instead of undertaking it as a redevelopment project with preservation elements. However, with no thorough considerations on the ways that conservation would affect people s way of life, the project has attracted a lots of criticisms. Apart from the URA, the Commissioner for Heritage s Office (CHO) of the Development Bureau which was established in 2008, launched the Revitalising Historic Buildings Through Partnership Scheme for the government owned historic buildings (Development Bureau, 2012). A total of fourteen historic buildings which are situated in the old urban districts have been announced since The social impact of the reusing the historic buildings on the community has yet to be examined. After understanding of the background of the research context, it shows that there are only fragmented findings in the literature on the social impacts of revitalization of historic buildings in urban renewal. Many controversial issues still remain in the topic and there is not yet any comprehensive framework developed. Therefore, this study contributes to build the theoretical assessment framework. Methodology 6

362 This study employed the qualitative research methodology to develop the robust theoretical framework for analyzing the social impacts of revitalizing of historic buildings in urban renewal. The research study is based on three phases. First, data collection from literature, and with simultaneous analysis of the data by conceptualising and reducing data, elaborating categories (Backman and Kyngäs, 1999; Strauss and Corbin, 1998). In this first phase, it also employs in-depth interviews discussion with experts in the field; second, it uses case studies of revitalizing historic buildings in urban renewal in Hong Kong to further evaluate the applicability of the factor; and finally, corresponding indicators will be developed with the involvement of the general public. 1.Literature review A list of social impacts Identify controversial social issues of revitalizing historic buildings in urban renewal 2. Experts interviews Validate and refine the list of social impacts Examine the contentious issues in evaluation Phase I Theoretical framework for assessing social impacts of revitalizing historic buildings Phase II 3. Surveys (Public participatory approach) Validate the ease of understanding and degree of relevance of the corresponding indicators Phase III 4. Case Studies Validate and refine the list of social indicators Refine the list of social impacts and develop the corresponding indicators Refine the list of social indicators 5. A set of qualitative and quantitative Social indicators Figure 1. Research methodology adopting in this study 7

363 Literature review This study began with an extensive review of books, professional journals, conference papers, government reports, local publications, newspapers, urban renewal authority s publications, internet resources, etc. to capture relevant background knowledge. The literature review helps to develop a framework for this study and prepare for the list of social impacts of revitalization of historic buildings in urban renewal. In-depth Interviews with experts A panel of experts was invited to participate in the process of developing a list of critical factors for evaluating the social impacts of revitalizing historic buildings in urban renewal districts. The experts chosen are professionals and academics who have at least fifteen years of working experience in the field of urban design, planning, architecture and heritage conservation in Hong Kong (table 1). During the in-depth interviews, they provided the list of preliminary critical factors developed by the research team and asked to evaluate the validity of each factor and the corresponding evaluation questions to the local context of Hong Kong. Table 1 Profile of the expert s panel Name Field of expertise Affiliation Prof. A Urban design and Professor, The University of YY, Hong Kong architecture Prof. B Heritage Conservation Professor, The University of YY, Hong Kong, TPB Dr. C History Associate Professor, The University of ZZ, Hong Kong, AAB and TPB Dr. D Planning, urban renewal and social impact assessment Research Institute on Sustainable development, The University of WW, Hong Kong, Prof. L Architecture, Urban The University of WW, Hong Kong, TPB Planning and urban renewal Mr. E Heritage conservation Member of Heritage and Conservation Committee of a Professional Institute, AAB, active critics and journalist Mr. F Town Planning and heritage Senior manager, Community development, Urban Renewal Authority conservation Mr. G Social work Senior manager, Community development, Urban Renewal Authority Dr. H Urban Design and urban Professor, The University of WW, Hong Kong, renewal Mr. J Urban development CEO of an NGO- Designing Hong Kong Mr. K Architecture and sociology Architect of several revitalization of historic buildings in Hong Kong Formulating social indicators Based on the refined list of social impacts of revitalizing historic buildings in urban renewal districts, the research team will develop the corresponding qualitative and quantitative indicators to assess the performance of the revitalization of historic building project. Instead of validating these social indicators with experts, this research adopts a public participatory approach to formulate the social indicators. It is argued that the laymen should be the respondents who evaluate the social impacts of the project on their everyday lives. The Phase III of the research intends to ensure that the developed indicators and are commonly agreed and are easily understood by the general public. Case Studies Two cases of revitalization of historic buildings in urban renewal districts in Hong 8

364 Kong will be used to test the developed list of indicators. The case of Blue House Clusters (figure 1) and the Lui Seng Chun (Figure 2) located in Wanchai and Mongkok respectively are chosen and they are located in two areas with distinctive characteristics. The case studies aim to examine whether the social indicators for the conservation of built heritage in different urban renewal districts varies. If so, the generic framework for assessing the social impacts of the built heritage project will need to be refined for different urban renewal districts. It intends to investigate whether and how the local context, socio-demographics, the urban renewal approach and the existence of other built heritage in the district affect the list of social impacts on the community. Figure 1. Blue House Figure 2. Lui Seng Chun Preliminary Results Initially, a total of 16 social impacts shortlisted from the literature were scrutinized. For each social impact, elaborative statements are also provided for the better understanding of the impacts. Table 2 presents the final list of social impacts factors after the experts in-depth interview. The experts made critical comments on the validity of each of the factors and their elaborated statements proposed to be used for assessing the social impacts of the revitalization project in urban renewal during the in-depth interviews. The interviews took about one and a half to two hours. Some of the social aspects which are not agreed by more than 50 % of the experts were deleted. It is proposed that this list of social impacts should form a generic template for future evaluation of revitalization projects and different list of social impacts would be applied to each specific project. Table 2. Social impacts of revitalizing historic buildings in urban renewal Social impacts Sub-factors (Elaborated statements) The revitalization of historic buildings has the following impacts: 1. Sense of place want to stay in the historic building(s) the historic building(s) is alive with people moving and or stationary activities is/are happening in the heritage building(s) the historic building(s) can be easily differentiate from other places in the district the historic building(s) provides a multi-dimensional experience to you (ie. views, sounds, scents, textures, tastes, movement, individual impression, etc.) 9

365 2. Collective Memory 3. Cultural identity 4. Local characteristics and Uniqueness 5. Educating the present and future generation 6. Cultural diversity 7. Community interaction and social cohesion 8. Accessibility of use 9. Social inclusion and gentrification 10. Developing skills in heritage restoration and related activities 11. Public involvement opportunity provide tangible physical evidence of the past of the renewed district provide intangible evidence /symbols for people to get in touch with the past (e.g. the character defining elements). enhance everyday lives, communications and meanings attached to the district before the renewal provide the link between the present society and the people and historic event in the past a deep bereavement when you saw or heard that heritage building(s) was torn down provide a sense of pride convey an identity for yourself and/or a particular group of people help us to link to our roots and the past is/are an important symbol for the district provide meanings that are marked out by identity become a landmark in the local district conserve unique traditional businesses and industries continue the social everyday lives of the people enhance diversity of streetscape more variety of things to see and do enhance diversity of townscape more variety of things to see and do More programs/ workshops related to the historic building(s) (e.g. school activities / guided tours per month) compared to 5 years ago Illustrate the economic and scientific development took place in the district: - The heritage building(s) recalls history of traditional old trades and businesses in the local district. - The heritage building(s) reflects the economic and/or science, technological, and city planning development retain and respect the variety of local traditional trades and business retain and respect people with different nationalities retain and respect different values, beliefs, traditions establish forums for dialogue between diversified cultures foster creativity in all its diversity provide opportunities for meeting new friends provide opportunities for developing social bonding provide opportunities to take part in any heritage related community events enhance ease of maintaining close relationship with the old local neighbors enhance trust in other people enhance interdependency public are allowed to visit the heritage building(s) provide affordable access to the heritage building(s) for the general public, if entry fees apply (including the disadvantaged groups) public transports are within a manageable walking distance from the site provide satisfactory disabled access for people with special needs increase job opportunities related to heritage activities increase the property price and rent in the renewed district improve the neighbourhood more workers/ professionals know heritage conservation skill compare to 10 years ago more volunteers or paid works in heritage related activities for the local community (e.g. tour guides) and research compare to 10 years ago Public involvement activity/activities includes: public consultation forums with government officials on the future use and operators of the historic building(s) participatory design workshops/ exhibitions during the design stage public involvement in decision makings related to the use of historic building(s) 10

366 on going communication between the future building operator and the community Adopt partnership opportunities between the public and private sector Effectiveness of the public involvement activities: The public views obtained through different channels during the process of the conservation of heritage buildings are well addressed Different stakeholders are able to share the fruits of the conserved heritage site Recommendations and future study This study addresses the important role and social impacts of revitalizing historic buildings on the community in the context of urban renewal. Within urban renewal policy and practice, the application of the developed critical evaluation questions can be significant in measuring the social impacts of revitalization of historic buildings on urban renewal. This current paper presents the initial attempt of the whole study. It completed the phase I of the study which asked the experts to refine the list and identify the underlying issues in assessing social impacts. Phase II of the study requires further validation and refinement of the framework with case studies. Sample cases of revitalization of historic building projects in urban renewal districts will be selected for analysis. It needs to consider the time horizon and thereby incorporate a longitudinal, prospective design to reveal the long-term social impact and change over time. Interviews can be conducted for residents, business owners, and workers living in the urban renewed areas which contained revitalization of historic buildings. Possible mitigation measures should be provided to tackle the social impacts identified. Finally, a list of robust qualitative and quantitative social indicators will be developed with the participation of the general public. References Amit-Cohen I. (2005). Synergy between urban planning, conservation of the cultural built heritage and functional changes in the old urban center the case of Tel Aviv. Land Use policy, 22, Atkins Heritage and Institute of Field Archaeologists. (2004). Measuring the Social Contribution of the Historic Environment, a project by the Institute of Field Archaeologists and Atkins Heritage for the National Trust, London, available at: (accessed 10 November 2009). Ashworth, G.J., Graham, B. & Tunbridge, J.E. (2007). Pluralising pasts:heritage, identity and place in multicultural societies. London: Pluto Press. Assmann J. (1995). Collective memory and cultural identity, Czaplicka J (transl.). New German Critique 65, Australia ICOMOS. (1999). The Burra Charter, The Australia ICOMOS Charter for Places of Cultural Significance. Australia ICOMOS Inc. Barthel, D. (1996). Historic Preservation: Collective Memory and Historical Identity. New Brunswick, NJ: Rutgers Univ. Press. Boyer M.C. (1996). The city of collective memory its historical imagery and architectural entertainment. MIT Press. Bramley, G., & Power, S. (2009). Urban form and social sustainability: the role of density and housing type. Environment and Planning B. 36, Chan, E.H.W. & Lee, G.K.L. (2008). Critical factors for improving social sustainability of urban renewal projects. Social Indicators Research, 85, Cheung, CK & Leung, KK (2012). Social Mitigation of the Impact of Urban Renewal on Residents Morale. Social Indicators Research, 106, Clark, K. (2001). Planning for the past: heritage services in local planning authorities in England. Cultural Trends, 11 ( 43/44), Coeterier, J.F. (2002). Lay people s evaluation of historic sites, Landscape and Urban Planning, 59, 11

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370 SUSTAINABLE PLANS FOR AN URBAN CITY HONG KONG REGIONAL CONFERENCE Mansi Talwar Washington, D.C, United States of America 1

371 SUSTAINABLE PLANS FOR URBAN CITY ABSTRACT In the past we have seen the population increasing exponentially and majority of the young dwellers prefer to live in an urban environment where they can have access to a fast paced life and also good career opportunities. By the end of 2050, a major chunk of the population will live in tiny apartments of high rise buildings. There will be an increase in the number of urban cities and a need of vertical growth. There are various world population statistics that can predict the need of infrastructure development and a need for change in order to handle the growing needs. It has also been observed that the current carbon content as of June 2013 is ppm the atmosphere. Further, with the resources diminishing, there is an additional need to demonstrate sustainable practices. However, sustainability is still a vague phenomenon for many, the definitions are not clearly understood. Also, sustainability and green are not exactly the same terms and their definitions may overlap each other. Sustainability plays a bigger role than green in infrastructure development which has been presented in this paper. Various methods can be implemented to improve the sustainable standards for urban buildings. Create awareness through education, green rating systems, rebates or even policy and regulations. The green rating system methodology is an impressive tool and somewhat beneficial. Rebates can be a good start by providing financial incentives for sustainable green innovations. Additionally, government policies enforcing sustainable practices can be beneficial to achieve a stable urban environment. A Case study has been presented in this paper to describe the implementation of these programs. These methodologies can be truly inspirational to develop sustainable policies for developed and developing nations.. Keywords: SUSTAINABILITY, POLICY, ENERGY, LEED, PLANS 1. INTRODUCTION Urban living allows humans to develop diverse economies with an ambition of constant growth and prosperity. Attempts are constantly made to develop a stable place called home which would be resistant to various volatilities in human life. Water, stable landmass and gentle climatic conditions were traditionally the reasons why development of human habitation was closer to water ways. However, trends and values have evolved and various additional factors motivate mankind to move to an urban environment. As a result, by 2030 an estimated 60% of the world s population will be living in an urban area (Collin, 2009). We live today in a resource intensive society where resources are limited and these should be used prudently. The damage to natural and ecological resources cannot always be quantified. Hence there is uncertainty about the possible scale of damage to the environment leading to irreversible consequences such as global warming. Overcoming obstacles should be our primary source of attention and we need to address them with an integrated sustainable approach that can help support infrastructure redevelopment. 2. SUSTAINABILITY AND SUSTAINABLE DEVELOPMENT Sustainability has various definitions based on individual perception. I understand it as a noun for best management practices that support social, economical and 2

372 environmental factors. These factors are foundation for making a better society, and if all processes (construction, manufacturing, energy generation, etc.) are accomplished sustainably, we can create a better and more stable economy. The application of sustainability in the building sector has been one of the hardest tasks. Organizations such as World Bank, International Finance Corporation, Department of Energy, and International Energy Agency have all been working on a global scale to focus on solutions and implementation of sustainable practices. When the word sustainability is paired with development and community it gets more complicated and ambiguous creating a wider scope and confusion with regard to the precise definition. The whole concept of sustainable development has emerged to focus on creating an environment for high quality of life. This is not just about minimizing resources but also maintaining an ecological balance along with creating a balanced economy and hence community. We spend most of our time performing activities that are indoors; at our work place, in our house, school, shopping mall etc. Creating a sustainable environment in these spaces would promote a healthy environmental quality and hence increase the productivity of individuals which is a cherry on top with saving scarce resources such as water and energy. However the real difficulty lies not in the reality of the concept but in the operationalization (Mazmanian, 2009). This paper will further discuss in section 5 the different approaches considered by District of Columbia (DC) and the local jurisdictions that could help ease the implementation process. 2. POLICY, GREEN CODES AND ECONOMICS Energy policy and green codes would require governments to place constraints on developments in order to meet stringent standards. These standards, to protect the environment have evolved through a process of trial and error, since their inception. Implementation of constraining policies can at times come with the cost of economic growth of some businesses and migration or extinction of some industries creating panic. If certain dynamics are overlooked and not quantified, the policies may be rendered ineffective. Unfortunately, there are no decisions which are risk free and would always raise public concern. On the other hand, realistic policies and green codes can also create new jobs and industries. However, the true vision of these policies is to create smooth processes that enable transition towards green growth and create an opportunity for the inhabitants to reach an agreement on how to progress towards the achievement of multiple goals. Green Policies implemented in cities such as DC have created a difference in the way businesses and industries work. It all began with implementing the less ambitious standards. With a handful of organizations implementing it and the market becoming competitive, the standards created a trend. Slowly more ambitious standards were put in place. Today there are greater number of green cleaning, recycling, composting and waste management services than there were 10 years ago. The city has had a strong political support and has created numerous programs and processes of implementation without which DC would not be as sustainable as it is today. However there is still a lot of room for progress for the future. DC has been somewhat successful in implementing the Green Building Act to target high sustainability standards for different building sectors which basically created standards and expectations for new and existing buildings with benchmarks for green 3

373 building rating systems and energy performance reporting. These are well established and trusted standards. Today most countries have developed their own green building codes and standards, but the biggest challenge has been the implementation. Certain rebate and incentive programs have been used to facilitate the implementation. This is elaborated further in this paper. 3. GREEN BUILDING RATING SYSTEMS U.S Green Building Council, a nonprofit organization formed in 1993 created a voluntary program called Leadership in Environment and Energy Design (LEED) and released its first version in The program was introduced to support sustainability, healthcare and help develop buildings which will be efficient and cheaper to maintain. The first version of LEED rating system was created for new construction and it guided standards and benchmarks which were comparatively easy to achieve. After its initial success, programs were developed creating guidelines for existing buildings and commercial interiors and existing buildings were also developed which eventually became building standards. Architects, land use planners and civil engineers realized the value the standards brought to the community, and hence the industry transformed. The trend encouraged vendors to think outside the box and understand the concept of cradle to cradle and create sustainable products that neither existed before nor were promoted. Further, the concept Social Corporate Responsibility became popular wherein organizations aim to create a portfolio of LEED certified buildings to give them a better brand value. Today companies prefer to lease a LEED certified building since it adds value to their brand along with enhancing the productivity of their employees. USGBC also provided education and awareness through their Green Education programs, which brought building operations in spotlight. Today, USGBC has 12,858 member organizations, 46 regional chapters, 21,372 staff, volunteers and 41,307 registered and certified LEED projects and counting. Over the years, the rating systems became more stringent; with the upcoming version (4) due to be released in November Professionals from various backgrounds such as Mechanical Engineering, Electrical Engineering, Urban Design, Architecture, Property Management and Environmental Sciences have been instrumental in the creation of this rating system. The new rating systems may be difficult to achieve, however building owners and developers are motivated enough to design and build buildings which conform to the highest certification levels and are still able to compete in the real estate market. As a result of which, at present we have better and more efficient buildings in the market. The success of these rating systems also lead to the rise of similar green building councils in many other countries such as, Singapore, Hong Kong, India, Canada, etc, which in turn created their own rating systems. 4. INITIATIVES ON A MUNICIPAL LEVEL The popularity of terms like green and sustainable is great but the biggest problem is their operationalization and implementation. People always try to make intelligent choices and spend their money in the right places so it is important to make them understand the monetary advantages of sustainable buildings. Just as all the big undertakings have to start at a small level, there is a need to initiate sustainable programs in a municipal/regional level to start. In this spirit DC metro area introduced 4

374 programs that were implemented as a part of building codes and energy policies that discussed further below in this section. 4.1 GREEN BUILDING CODES DC is considered as one of the national models in United States for green building construction. There are more than 300 LEED certified projects and about 700 currently in the pipeline. Base on the census data of 2010, DC has been ranked as the top most candidates to achieve the highest LEED certified space per person in The ability of green building rating systems to create such a big difference was enough of a driver to create the Green Building Act 2006 (GBA) which was finally enacted in January Policies and regulations are not easy to enact and took a significant amount of effort of the lawmakers especially in this politically influential place. One of the reasons for the delay in code enactment was the requirement of a performance bond which was mandatory for all contractors in order to get the contracts approved by DC government. GBA was originally created for only public buildings, but as of January 2012 the act has set standards for private buildings as well. The GBA set standards are listed as below PUBLICALY OWNED BUILDINGS BENCHMARKING: Buildings have to be designed to achieve Environmental Protection Agency s (EPA) national energy performance rating system defined by ENERGY STAR Target Finder Tool for buildings of size 10,000 sq. feet or more. The actual energy usage will be compared with benchmarking data and the statements will be made public. LEED: All non-residential projects have to meet and exceed the requirements of LEED for New Construction version 2.2 and LEED Core and Shell rating system version 2.0 rating systems. GREEN COMMUNITIES: Residential buildings of area greater than 10,000 sq. ft. have to meet the Enterprise Green Community Standards which provide universal design specifications for single and multifamily buildings. This program is specifically focused on affordable housing so that a green future can be provided for affordable housing PRIVATELY OWNED BUILDINGS All nonresidential buildings of area greater than 50,000 sq. ft. need to provide documentation of green building elements in the permit process and verify within 2 years of occupancy that all the green building elements pursued were implemented. The buildings have to meet or exceed the requirements of LEED for New Construction version 2.2 or LEED Core and Shell version 2.0 at the certification level. Further, all educational facilities should meet or exceed the LEED for schools standard. There are no requirements for residential buildings. However, it should be noted that most of the new residential buildings are being constructed based on sustainable standards due to competitiveness in the market. Further, the sustainability plan 2013 created by the Mayor of DC aims at certifying all public buildings to at least LEED Gold or equivalent standards. Also by 2032, the sustainability plan is to meet net-zero standards for all public housing. The overall goal is to achieve the highest efficiency standards for buildings, and aim for net zero 5

375 building efficiency standards for all new constructions. There are similar standards being enforced in adjoining jurisdictions to DC. 4.2 CASE STUDY: SOUTH SECURE OFFICE, ARLINGTON, VIRGINIA The closest suburb to DC, Arlington County is undergoing massive redevelopment and also has a stringent zoning ordinance which LEED certification and the level of certification depends upon a case by case basis. The Administrative Regulation 4.1 that is governed by the Department of Community Planning, Housing and Development is a part of the Planning Division of Arlington County and requires a site plan submission that includes information of how the project will meet requirements of the voluntary USGBC program of LEED. These green building components will be a part of site plan negotiations in exchange for the requested bonuses that will be analyzed on a case-by-case basis based on the characteristics of individual sites. One of the projects I participated in was the Founders square development in the Ballston area. Previously a gas station is now a mixed use development that will have Residential, Hotel and Commercial buildings along with pedestrian friendly walkways and open spaces. This includes 28,000 sq. feet of Retail Space and 775,000 sq. feet of Office/Residential space. One of the buildings in this development that I was closely involved with was the thirteen story commercial building. Shooshan Company who was responsible for this project is a family owned Arlington County based developing company and is conscious about sustainability and hence were glad to be focused on achieving the LEED certification requirements of Arlington County. The site plan submission process for the thirteen story commercial building included new site plans, information regarding major amendments to existing site plans and the phased development of site plans pursuant to the Zoning ordinance of Arlington County. The submission also included the LEED scorecard and a summary of energy and water savings. The LEED scorecard also has to be provided with a brief justification of why credits can or cannot be achieved for this project. Once the county manager has a chance to review; and site plan submission has met the requirements of the regulation through this very tedious public review process, the permit drawings are presented to the county in order to comply with zoning conditions which typically involves: 1. Sustainable compliance with the character of the master plans, area development plans with the uses permitted and use regulations set forth in the zoning ordinance or may be applicable for modification by the board. 2. Relates to other structures permitted in the district and improves the quality of the neighborhood. 3. Located in an area where the public health, safety and welfare will be promoted. This high performance high rise office building had to achieve a LEED Core and Shell Gold Level Certification as required by Arlington County and the tenant was required to achieve LEED CI Platinum level achievement based on their organization s Green Building Policy requirements. Hence the performance expectation of this building is extremely high. The site plan permit process for this project required them to submit a bond of 1 million U.S dollars with Arlington County demonstrating their commitment to achieve LEED certification which will be received once the certification is achieved. 6

376 The building focused on minimizing resources and maximizing indoor environmental quality. The building achieved 40% potable water use savings against the LEED baseline and through the specification of efficient HVAC, lighting, and energy star appliances, the tenants achieve significant energy savings. The use of motion sensors, multi zone lighting and motorized shades that can be controlled through their computer enhances the experience of the occupant by controlling the daylight they need and also views to the outside. Additional features such as permantaly installed walk off mats, high efficiency filtration, carbon dioxide monitoring, and increased ventilation contributes significantly to a high level of indoor air quality without compromising energy efficiency. This is a great example of how the permitting process, individual green building policy and the awareness of a developer contributes to the success of a sustainable building. Further, the involvement of the bond certainly initiates a stressful process and creates pressure to achieve the required targets. Although not all credits in the LEED rating system increases the performance of the building such as transportation and development density but it definitely provides an incentive to encourage occupants to reduce the vehicle miles traveled and create a sustainable living. 4.3 GREEN FEES AND REBATE PROGRAMS Direct and indirect monetary benefits in the form of taxes, subsidies and zoning ordinances are one of the ways government can influence choices in the private and public sector. These tools of government can rationally be applied in a broad variety of ways to deter unsustainable behaviors and to encourage sustainable behavior (Collin, 2009). The case study described in 5.2 is a type of indirect monetary benefit as the developer is given an incentive through the zoning ordinance to develop a thirteen floor commercial building if they consider achieving a LEED Core and Shell Gold level Certification. This is an indirect monetary benefit since the developer will make money on the rent of this commercial space for the entire lifetime of the building. Taxes can be added in order to make the product less desirable and hence decrease the consumption. However, taxes require a long and tedious legislative enactment and are tedious to implement. Instead of taxes another model that can be implemented are green fees. Fees are costs that are added to the cost of a product which can be used to benefit the community. An example has been specified further. On a municipal level it can act as a short term economic tool by raising capital for infrastructure or in the form of short term tax breaks or direct payments. In DC the Mayor and The District Department of Environment (DDOE) adopted a unique route to achieve the goal of energy efficiency through The Clean and Affordable Energy Act Enacted in 2008, it has a unique vision of providing DC residents and business technical and financial assistance to save energy. The act establishes authority to contract with a private company to be known as a Sustainable Energy Utility (DCSEU) to administer sustainable energy programs in the District of Columbia (Daniel, 2009).This Company is responsible for reducing per capita energy consumption, increase renewable energy generation, reduce peak electricity demands and improve energy efficiency in low income housing. Also, as an offset increase the number of green collar jobs. 7

377 Two of largest utility companies in DC, Potomac Electric Power Co and Washington Gas charge an additional amount to their customers in their utility bill which then is pooled together for a Sustainable Energy Trust Fund. This amount is then invested in DCSEU to initiate various programs aimed at energy reduction and conservation that covers wide base of consumers. DCSEU rations this fund and provides a reasonable rebate for projects within the city that reduce their annual energy consumption. For example, DCSEU will provide rebates for a part of the PV panel installation on the roof of low income multifamily building. Traditionally low income housing buildings have been constructed with cheaper insulation materials and appliances, resulting in a high maintenance cost. Adding the photovoltaic array can help reduce the monthly utility bill. The act also requires eligible buildings to benchmark their energy use annually which will be made publically available. The idea is to create transparency through public disclosure will motivate all parties to participate in energy efficiency and meet the energy saving goals. This is an efficient program as the money is continuously recycled through the utility bills, unlike other rebate programs. Although the rebate model seems easy to navigate and manage there are some cons to it as well. Vendors can false market their products with the rebate programs and dupe unwitting customers to enhance their sales. This can be mitigated by giving the appropriate technical guidance to the consumers. This program can be easily emulated by other cities specifically those which have similar demographics and economies like DC. 5. CONCLUSION President and Founding Chairman of USGBC Rick Fedrizzi on the occasion of approval the final draft of LEED version 4 rating system said that LEED has driven deep and permanent change into building practice, public policy, product development, financial infrastructure and consumer choice, but we ve only just begun. It does not have to be just LEED, but any rating system and/or policy that is compatible with the politics and economics for your region can make a positive difference to the economy, infrastructure, human health and environment. Our current knowledge for creating sustainable buildings may not be sufficient, but as we move forward our experiences will bridge that gap. 6. REFERENCES Bland, K., [ONLINE] Available at: s.pdf. [Accessed 12 July 2013] Clean and Affordable Energy Act of 2008 doe Clean and Affordable Energy Act of 2008 doe. [ONLINE] Available at: [Accessed 12 July 2013] Collin R. M. and Collin R. W., Encyclopedia of Sustainability: Volume I: Environment and Ecology. Edition. Greenwood Collin R. M. and Collin R. W., Encyclopedia of Sustainability: Volume II: Business and Economics. Edition. Greenwood. Collin R. M. and Collin R. W., Encyclopedia of Sustainability: Volume III: Equity and Fairness. Edition. Greenwood. 8

378 Department of Community, Planning, Housing and Development, Arlington, VA [ONLINE] Available at: Regulation-4.1.pdf. [Accessed 12 July 2013] Directory U.S. Green Building Council Directory U.S. Green Building Council. [ONLINE] Available at: [Accessed 12 July 2013] Green: Green Buildings green: Green Buildings. [ONLINE] Available at: [Accessed 12 July 2013] Green Building Act of 2006 ddoe Green Building Act of 2006 ddoe. [ONLINE] Available at: [Accessed 12 July 2013]. Hardoy, J. E, Miltin, D. and Satterthwaite, D., Environmental Problems in an Urbanizing World: Finding Solutions in Cities in Africa, Asia and Latin America. 2 Edition. Routledge Mazmanian, D. and Kraft, M., Toward Sustainable Communities: Transition and Transformations in Environmental Policy (American and Comparative Environmental Policy). second edition Edition. The MIT Press Sustainability: A Comprehensive Foundation Sustainability: A Comprehensive Foundation. [ONLINE] Available at: [Accessed 12 July 2013] Technical Components of the Green Building Density Incentive Program - AIRE Technical Components of the Green Building Density Incentive Program - AIRE. [ONLINE] Available at: [Accessed 12 July 2013] #LEEDWorks the green building community has spoken U.S. Green Building Council #LEEDWorks the green building community has spoken U.S. Green Building Council. [ONLINE] Available at: [Accessed 12 July 2013] 9

379 MODELING URBAN HEAT ISLAND EFFECT IN A RESIDENTIAL DEVELOPMENT IN HONG KONG Henry C.B. Au 1, S.H. Yan, Vincent S.Y. Cheng, Ove Arup & Partners HK Ltd, Level 5 Festival Walk, 80 Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong 1 Corresponding Author henry.au@arup.com, Tel: (852) , Fax: (852)

380 MODELING URBAN HEAT ISLAND EFFECT IN A RESIDENTIAL DEVELOPMENT IN HONG KONG ABSTRACT Considering the environment deterioration due the intensive urban developments, it has become increasingly important to study the effects of urban heat island (UHI) effect in the urban and estate planning to improve the environment. However, this effect has often overlooked in the planning process in practice. The reason for this is the lack of guideline and method for quantifying the UHI phenomena during the planning process, which is challenging for architects, urban planners to implement mitigation strategy. This paper shall present an innovative approach to overcome this challenge by using analytical approaches and advanced simulation techniques to quantify the UHI effect. This paper will also demonstrate a case study in Hong Kong to shows the thermal effects of some major design control elements, such as the effects of building density and disposition, the effects of shade trees and buildings, the effect of greenery and water features modification. The findings of this paper will guide us to create more sustainable communities, and thus reduce UHI effect with the intensive urban context and improve the quality of life of people living in the city. Keywords: Urban Heat Island; Built Environment Modeling; Urban Climate and Liveability; Integrated Design and Planning; Building Sustainability. 1. INTRODUCTION The rapid urbanization and industrialization has caused the urban environmental deterioration [1]. It results a hotter urban environment while compared with the rural site. This phenomenon is known as Urban Heat Island (UHI) effect. Hong Kong is highly urbanized with approximately 7 million people living in an area of 1,100 km 2. The demand for land far outweighs the amount of available space. Over the last few years, we have witnessed the intensive urban developments, causes rapidly rise of urban temperature and reduction in urban wind speed, which has magnified the UHI effect in the city. Nichol J [2] shows that the temperature in the urban center in Hong Kong can be up to 12 higher than that of the rural areas. The report from Hong Kong Observatory (HKO) [3] also shows that the urban area has been warming up at a rate of 0.4 per decade more compared to rural area. There are several factors which affect the UHI effect, such as meteorological factors which are not subject to human intervention. Examples include regional wind speed, global temperature, solar radiation, humidity and cloud cover. The urban geometry created by human beings would also have significant influences to the UHI effect, the most important factors of which are summarized as follows [4], (1) Increase storage of sensible heat in the fabric of the city; (2) Multiple reflection of shortwave radiation between the building surfaces; (3) Complex geometry of urban areas reduce the airflow and reduces the turbulent transfer of heat from within streets; (4) High intensive urban geometry that contributes to the decrease in long-wave radiation loss; and (5) Reduction of evaporating surfaces, thus energy is put into sensible heat and less into latent heat. Modeling approach can be used to quantify the UHI effect during the planning process and suggesting ways for mitigating the UHI problem. This paper shall present an innovative modeling approach for quantifying the UHI effect within the urban cluster. A case study in Hong Kong will also be demonstrated to determine the thermal effects of 2

381 some major design control elements. And thus we are able to optimize the building design through this sensitivity analysis to mitigate the undesirable effect and improve the quality of life of people living in the city. Nomenclature convective heat exchange factor of shading / trees power law exponent cluster thermal time constant the partial vapour pressure (Pa) partial shaded area from the buildings on the ground (m 2 ) average evaporative mass flux partial shaded area from the trees on the ground (m 2 ) velocity at height z (m/s) surface area (m 2 ) reference velocity at height (m/s) Total open space area (m 2 ) daily averaged heat island intensity of the site ( ) d road surface heat island intensity of the site ( ) B green roof surface heat island temperature at the urban area ( ) YD hard paving surface heat island temperature at the meteorological station ( ) c plaza surface t Time (hr) L grasses surface air velocity (m/s) s water surface height above ground (m) T tree coverage reference height (m) Temperature changes due to solar solar transmittivity of the shading / radiation ( ) trees Temperature changes due to latent heat exchange ( ) Brunt number Temperature changes due to long wave radiant exchanges ( ) Stefan-Boltzmann constant the unobstructed solar radiation the solar radiation absorptivity of the intensity incident on a horizontal surface (W/m 2 surface ) the direct solar radiation intensity (W/m 2 ) the sky diffused solar radiation intensity (W/m 2 ) surface convective heat transfer coefficient (W/m 2 K) sky view factor 2. METHODOLOGY The analytical model used in this study derived from the principles of the cluster thermal time constant (CTTC) model, introduced by Hoffman and Swaid [5]. The model (hereinafter The UHI Model ) equations were further enhances from its predecessor based on the literatures [6]. A brief outline of the model s basic theory is given below DAILY AVERAGED HEAT ISLAND INTENSITY The daily averaged heat island intensity,, is used to quantify the intensity of the UHI effect, which is the variations of the heat island temperature between the urban area and meteorological station from 8am to 8pm in a typical summer day. The daily averaged heat island intensity is defined by: (Eq: 1) The heat island temperature,, of the site can be expressed as the sum of the contributions in energy balance during a certain time, (t), which includes the air temperature changes due to (1) the contribution of solar radiation,,(2) the 3

382 contribution of long wave radiant exchanges, heat transfer in the environment,., and (3) the contribution of latent (Eq: 2) 2.2. CONTRIBUTION OF SOLAR RADIATION Solar radiation is radiant energy emitted by the sun, where absorbed by the atmosphere and the heat emitted by the earth increase the air temperature. The time dependent contribution of the solar radiation (direct + diffuse) to air temperature,, given by the following equations: (Eq: 3) ( ) [ ] where (Eq: 4) The absorptivity of a material, is the relative ability of its surface to absorb energy by radiation, usually from the solar. The area-weighted average absorptivity of the surface to solar radiation ρ is given by (Eq: 5) where (Eq: 6) consider the thermal effect of the direct and diffuses solar radiation on the horizontal surface and includes the effect of shading effect from the buildings / trees. The thermal effect of the shade trees is estimated by the effect of solar radiation penetration through the tree canopy and by the intensity of evapotranspiration. The unobstructed solar radiation intensity,, incident on a horizontal surface is given by { } ( (Eq: 7) ) The ventilation inside the urban cluster could effectively remove the absorbed heat from heat and cool down the urban space. In, it also consider the air temperature changes from convection heat transfer between the outdoor air and the surfaces of buildings and ground. The air velocity,, dependent surface convective heat transfer coefficient,, is given by: (Eq: 8) Computational Fluid Dynamics (CFD) technique can be used to assessing the air velocity,, of the site. The fluid motion would be modelled by the Navier-Stoke equation. also incorporating a cluster thermal time constant,, for predicting the heat energy stored in the participating ground layer, building and trees surface areas per unit change in the heat flux through it. The CTTC model was developed by Swaid and Hoffman [5]. ( ) (Eq: 9) For the hard landscape areas, the CTTC value was found to be about 8 hours, and for typical building blocks the CTTC value was 6 hours, and 12 hours for trees [7] CONTRIBUTION OF LONG WAVE RADIANT EXCHANGES The contribution of the net outgoing long wave radiation flux, expressed by the following equations., to air cooling is 4

383 (Eq: 10) (Eq: 11) (Eq: 12) ( ) 2.4. CONTRIBUTION OF LATENT HEAT EXCHANGE Greenery and water features can reduce temperatures through evapotranspiration, which is the sum of evaporation and plant transpiration from the land surface to atmosphere. For latent heat exchange,, it would be given by (Eq: 13) The latent heat evaporative heat flux,, is obtained by (Eq: 14) (Eq: 15) 3. CASE STUDY The urban heat island intensity of an existing development site is investigated as a example. The development site is situated at the northeast (NE) regions of Hong Kong. The site area is around 12,000 m 2 and consist four high-rise residential building blocks. At the ground level, there are greenery space, two entrance spaces and one driving path along the boundary. The daily heat island temperature at both the site and rural areas were assessed for the summer periods INPUTS AND OUTPUTS REFERENCE WEATHER CONDITION The UHI Model requires hourly the reference weather data as inputs, such as air temperatures, wind speed, wind direction, direct and diffuses solar radiation. The data can be collected from the meteorological station. The heat island temperature at the meteorological station, is shown in Figure 1(h) OUTDOOR WIND SPEED Computational Fluid Dynamics (CFD) technique was employed in assessing the air velocity,, of the development area. The commercial CFD software STAR-CCM+ was used in this study. SST k ω turbulence modelling method was applied in this simulation which provides more accurate modelling of the turbulence level expected in an urban environment. The reference weather data shows that the summer prevailing wind directions are Southwest (SW) wind. The power law exponent, n-value, is used to present the urban surface roughness and assumed to be The reference velocities, is 3.03m/s and the reference height ( ) was 10mPD. The wind profile was assumed to follow the power law for specific terrains as given in equation (Eq: 16). (Eq: 16) The wind speed,, at 1.5m above ground level for summer is given Figure 1(a). The average wind velocity for the development site is around 2.2m/s UNOBSTRUCTED SOLAR RADIATION INTENSITY Radiance was also used as to evaluate the non-shaded area from the buildings on the ground, (1- ), and partial shaded area from the buildings on the ground,. The shading area ratio of the trees,, can be obtain from the total trees coverage area, 5

384 , divided by the open space area Using equation (Eq: 7), the unobstructed solar radiation intensity,, incident on a horizontal surface can be obtained. Figure 1(c). and Figure 1(d). show the shading effect of the development at 10am and 4pm, respectively, as a example. The non-shaded area from the buildings on the ground, (1- ), is shown in and Figure 1(f) SKY VIEW FACTOR Ray-tracing software system, Radiance was also used as the simulation tool for the analysis the sky view factor (SVF) study. The radiance model calculates the ratio between the direct sight to the sky and whole sky hemisphere at the open space area. Using equation (Eq: 3) and (Eq: 10) the air temperature changes due to the solar radiation, and net outgoing long wave radiation flux, can be determined. The average SVF for the development is Figure 1(b) shows the SVR distribution of the development site VEGETATION AND WATER SURFACE AREAS The geometrics information such as surface area and absorptivity of water surface, greenery, hard paving and green roof are used for equation (Eq: 3) and (Eq: 13) to calculate the air temperature changes due to the solar radiation, and the latent heat exchange, RESULTS Using the above equation (Eq: 1) - (Eq: 16) and the aforementioned analysis, the predicted heat island temperature throughout the typical summer day is calculated is shown in Figure 1(h). The daily averaged heat island temperature intensity for the development is about 1.1. The insolation at the urban cluster is the dominant factor of the air temperature rise. Figure 1(g) shows the peak temperature gain is at the late-afternoon period (around 4pm-5pm) and mainly caused by the short-wave radiation. This is because most of the open space is situated at the southwest region. The building towers will casts shadows on the open space in the morning (refers to Figure 1(c)). On the other hand, the open space will be exposed to direct sunlight in the afternoon (refers to Figure 1(d)). Figure 1(h) also shows the temperature for both rural and development site generally increase during the daytime (5am-6pm), and reduce during night time (6pm-5am). It is noteworthy that the temperature at the development site is lagging behind the rural areas. A portion of the solar radiation is absorbed and stored in the fabric of the urban cluster, and release the back to the space at the later time. Vegetation helps to reduce temperature in the development site. Figure 1(g) shows the cooling effect of the evaporative by vegetation during the daytime and the night time PARAMETRIC STUDY In this section, a parametric study for the development site was carried out to investigate the impact of design control parameters on the heat island intensity,. The design control parameters includes, (1) Sky view factor (SVF),, (2) Wind speed,, (3) Tree coverage,, (4) Water surface coverage, and (5) Grass surface coverage,. The results indicate that, wind speed has the most significant impacts to the daily averaged heat island intensity, while the SVF would has less impacts (refers to Figure 2(c) & (d)). It is note that the SVF and wind speed are both depends on the site layout, such as density, permeability and disposition of the buildings. The results suggested that the architects or urban planners should optimize the site layout as a first priority to mitigate the UHI problem in Hong Kong. 6

385 1- Sustainable Building 2013 Hong Kong Regional Conference (a) N (b) SW Wind (c) (d) (e) (f) (g) (h) Figure 1 (a) wind condition at 1.5m above ground level, (b) SVF at the site, (c) shading effect at 10am, (d) shading effect at 4pm, (e) The non-shaded area from the buildings on the ground, (f) Hourly evaporation rate (g) Heat island changes for short wave radiation, long-wave radiation & latent heat transfer and (h) Heat island temperature for rural and urban ( ) The landscape design parameters, such as water features, trees and grass coverage ratio have slightly less impact to the heat island temperature intensity as compared to the SVF and wind speed. Among these three parameters, water surface coverage would have the highest impacts, while grass coverage has the least impacts. It is noted that the solar radiation would dominate the heat gain in the urban cluster in the afternoon, and the factors regulating shading effect becomes the most important 7

386 factor. Figure 2(a) shows lower heat island temperature is achieved, for the site with 30% tree coverage as compared to the site with 30% grass coverage. Since trees can provide very high degree of shading, urban planners shall plants trees at hard-paved areas which are expose to direct sunlight during the afternoon. (a) (b) (c) (d) Figure 2 (a) heat island temperature for different landscape design features; and heat island temperature intensity, for different (b) grass, tree, water coverage ratio (c) wind speed and (d) SVF 4. CONCLUSIONS UHI effect should be considered in the urban and estate planning. A new analytical model is developed and proposed for predicting the diurnal air temperature in the urban cluster. Some important physical aspects were including in the model. These includes the shaded effect from the trees and buildings, the building disposition affects the ventilation performance, the heat storage effect on different materials and the evaporation effect of greenery and water features. This approach allows a good understanding of the UHI impacts of the changes in the design control parameters can help urban designers to develop effective mitigation strategies. The findings are summarized in below: The results show the layout design is the most important factor to mitigate the UHI problem. architects or urban planners should optimize the site layout, such as density, disposition, permeability of the building as a first priority to mitigate the UHI problem. Urban vegetation and water features also have a great influence on the urban temperature and radiation. Trees shall be placed at un-shaded hard-paved areas to maximum the benefit effect. 8

387 5. ACKNOWLEDGEMENTS The authors wish to give special thanks to Henderson Land Development Company Limited for providing valuable supports on this study. 6. REFERENCE [1] Santamouris M, On the impact of urban climate on the energy consumption of buildings, Solar Energy, Vol. 70, pp (2001). [2] Nichol J. Top-notch experts to assess impact of Urban Heat Island effects [online]. Available from: [Accessed 21 May 2008]. [3] Leung Y. K., Climate change in Hong Kong, Hong Kong Observatory, Technical Note No.107 [4] Oke TR. The urban energy balance, Progress in Physical Geography 1988;12, [5] Shashua-Bar, L. Hoffman, M.E. (2002) The Green CTTC model for predicting the air temperature in small urban wooded sites. Building and Environment 37, pp [6] Elnahas, M.M., Willimanson, T.J. (1997). An improvement of the CTTC model for predicting urban air temperatures. Energy and Building 25, pp model for predicting the urban canopy layer temperature. Energy and Building 38, pp [7] 林波榮, 李曉鋒 (2010) 居住區熱環境 控制與改善技術研究. 中國建築工業出版社. 9

388 SHAPING SUSTAINABLE CITIES HIGH-RISE DEVELOPMENT, CONNECTIVITY, PHYSICAL AND SOCIAL FABRIC Mary Chan 1 HKIA, MRAIC, RAIA, RIBA, Architect AIBC, LEED AP, BEAM Professional, BEAM Faculty Member of Hong Kong Green Building Council, China Green Building Council Green Building Label Manager, Head of Sustainable Building Research and Assistant Director of Dennis Lau & Ng Chun Man Architects and Engineers (HK) Ltd Hong Kong 1 Mary Chan mc@dln.com.hk, Tel: (852) , Fax: (852)

389 SHAPING SUSTAINABLE CITIES HIGH-RISE DEVELOPMENT, CONNECTIVITY, PHYSICAL AND SOCIAL FABRIC ABSTRACT Increased population and scarcity of land for development in Hong Kong are fundamental factors which lead to the need to develop high-rise development to meet the demand of space for various kinds of usage. Through the use of case studies, the importance of high-rise development, connectivity, physical and social fabric in achieving a sustainable city model will be discussed. Building types that will be examined include the following: (1) Mixed-Use Residential and Commercial Building Case Study: Double Cove, a large scale mixed use development in the sub-urban area of Hong Kong in Lok Wo Sha. Based on living in a park concept, a residential neighbourhood is developed with 21 high-rise residential towers, a shopping mall and extensive clubhouse facilities near the Mass Transit Railway station. Extensive greenery, connectivity to efficient transportation system and walkability through the provision of a 24-hours covered walkway are important concepts of this development. (HK BEAM 4/04 Provisional Platinum Rating, China Green Building Council Green Building Design Label - 3 Star Award, Green Building Award 2012 Merit Award, MIPIM Asia Award 2012 Best Innovative Green Building Bronze Award. (2) Mixed-use Office and Commercial Building Case Study: Hysan Place, a high-rise office and commercial development located in heart of Causeway Bay, a major commercial district in Hong Kong which is well known for its air pollution, density of development and traffic congestion. The provision of urban windows at various levels to help improve the air ventilation for the district, an energy efficient office tower, extensive vertical shopping mall and direct connection to the Mass Transit Railway station are important concepts of this development. (HK BEAM Plus Provisional Platinum Rating, USGBC LEED CS 2.0 Precertification Platinum Rating, Green Building Award 2012 Merit Award, MIPIM Asia Award 2012 Mixed Use Category Gold Award). Keywords: High-rise; Residential; Commercial; Office; Cities. 1. INTRODUCTION In cities with high population where land for development is limited, high density highrise development becomes an evitable solution to meet the demand for space to live and work. Hong Kong has been using the high density high-rise mixed-use development model to shape its urban and sub-urban development for many years. This has been a successful phenomenon. Such high-density, high-rise developments created neighbourhoods and communities developed with an efficient public mass transportation system are environmentally, socially and economically sustainable. Two type of such mixed-use development in Hong Kong will be examined through the use of the following case study projects: (1) Double Cove - a mixed-use residential and commercial development (2) Hysan Place - a mixed-use office and commercial development 2

390 2. CASE STUDY 1 DOUBLE COVE, A RESIDENTIAL AND COMMERCIAL DEVELOPMENT Figure 1: Double Cove - Master Layout Double Cove is a mixed-use residential and commercial development located in the sub-urban area of Lok Wo Sha. 21 residential towers are built around a 2-storey high podium containing a shopping mall and a large clubhouse with extensive recreation facility. The underground parking facility has provision for electric vehicle charging for use by residents as well as for visitors. A 24-hour covered walkway connects the development to the mass transit railway system. 3

391 Sustainable Design: Double Cove is a mixed-use residential and commercial development based on the concept of living in a park in a walkable community. To create the living in a park setting, ample green space is created with about 50% of the site area being designated as green area including an existing woodland to be preserved and the creation of an extension of the woodland plus green roof, green walls, water features and other landscape amenity areas. An all-weather 24-hour public covered walkway is provided in the middle of the park at the podium roof level to provide connectivity to the retail centre and the mass transit railway (MTR) for the neighbourhood. Covered walkway from the residential tower entrance lobbies at podium level connects directly to this 24- hour public walkway which enables residents to walk to the retail centre and the MTR. View corridors are created to minimize view obstruction to the neighbours. The residential towers are designed to create a stepped height profile to enhance daylight access. Residential towers are generally organized in pairs allowing greater separation or sky views between paired tower and the creation of high headroom open entrances for each pair of towers. These enable greater permeability to enhance better air ventilation and better air quality. Hybrid ventilation is adopted for the shopping mall to reduce energy use. Environmentally, Socially and Economically Sustainable Community: The Double Cove development is designed to meet high green building standards under the Hong Kong Green Building Council s BEAM 4/04 certification standard (provisional platinum rating) and China Green Building Label (3-Star). It is also the first residential development in Hong Kong to conduct a site-wide heat island simulation. The high density development ensures that a large residential community is established. The provision of a shopping mall to meet the daily shopping needs of the residents is important. The large number of residents will create a large customer base for the shops making the shops economically viable. The shopping mall will also create job opportunity for residents who may want to work close to home. The large clubhouse with extensive recreational facilities including a large indoor pool, a large outdoor pool, a basketball court, fitness centre and gym, bowling facility and other function rooms provides space and facilities for the community to socialise and enjoy. As most units in the residential towers are small, the clubhouse provides a much needed extension of living space for people within this community to relax and enjoy in spite of the limited private space within their own homes. The large park created throughout the development with lush greenery, water features, sculpture and children play areas provide yet another living space extension which also promotes an environmentally friendly, healthy community. The provision of the 24-hour covered walkway to the mass transit railway enable the residents of this development to connect to the rest of Hong Kong easily for getting to work, to school, to visit other shopping areas or to visit friends and relatives. The convenience of mass transit railway brings this community in close connection with other parts of Hong Kong making it a socially and economically sustainable community. 4

392 Figure 2: Double Cove Site Plan Showing View Corridors Figure 3: Double Cove - Building Sections Showing Stepped Height Profile 24-hour covered walkway Retail Centre Landscaped area inside Shopping Mall- open to public MTR Station Figure 4: Double Cove 24-Hour Covered Walkway to Shopping Mall and Mass Transit Railway 5

393 Figure 5: Covered Walkway for Public at Double Cove Figure 6: Covered Walkway for Residents at Double Cove 3. CASE STUDY 2 HYSAN PLACE, AN OFFICE AND COMMERCIAL DEVELOPMENT Figure 7: Hysan Place with Express Escalators at Lower Floors Figure 8: Hysan Place with Urban Windows and Sky Gradens Hysan Place is a mixed-use office and commercial development located in the heart of Causeway Bay, a major commercial district in Hong Kong well known for its air pollution, density of development and traffic congestion. 6

394 Sustainable Design The development is a 36-storey high-rise building with a multi-storey shopping mall at the bottom and a multi-storey office on top. Urban windows are introduced at various levels to enhance air ventilation for the neighbourhood based on air ventilation assessment using computational fluid dynamics (CFD) technique. Green roof, green walls and sky gardens are introduced to help reduce heat island effect. Hybrid ventilation is adopted at the shopping mall to reduce energy use. Office floors are provided with high performance curtain wall system with lightshelves, solar shading devices and low-emissivity double-glazing to allow sufficient visible light to enter while reducing unwanted solar heat gain and exterior noise. Operable vents are installed to facilitate the use of natural ventilation to reduce energy use. Express escalators are provided to the shopping mall to enhance efficient circulation to bring customers faster to the upper retail floors. The building is directly connected indoors at the basement to the mass transit railway station to enhance the use of public transportation. Environmentally, Socially and Economically Sustainable Community The Hysan Place development is designed to meet high green building standards under the Hong Kong Green Building Council s BEAM Plus certification standard (provisional platinum rating) and U.S. Green Building Council s LEED Core and Shell (precertification platinum rating). It is also the first attempt in Hong Kong to integrate low level urban windows and oasis at the most expensive commercial area to encourage urban ventilation and to alleviate pollution problem which help to enhance the environmental quality of the neighbourhood. The high density mixed-use development with office and commercial use ensures that the office community and the shopping mall community will thrive with synergy. Office workers will benefit from the convenience of shops and restaurants downstairs while the shopping mall will benefit from the patronage of the office workers for better business. Direct connection of the shopping mall to the mass transit railway station at the basement enhances the use public transportation and reduces reliance on use of private motor cars. This also enhances the operation and value of the office and shopping mall as they can be conveniently reached by customers from other parts of Hong Kong using the mass transit railway. The trend of creating vertical shopping spaces is becoming common in Hong Kong due to the scarcity of land and high cost of shop spaces at ground level. In many commercial districts, shops and restaurants have moved into the upper floors of older buildings previously built for residential purpose since the rent for higher floors in these buildings are more affordable. However, vertical circulation in terms of lifts in these older buildings is often not sufficient to meet the increased demand. The resulting vertical shopping mall being created as an organic growth of the city of Hong Kong is surviving but not optimized due to inefficient vertical circulation. In contrast, the vertical shopping mall in Hysan Place is purposely built with express escalators in addition to lifts to enhance more efficient vertical circulation, making the shops and restaurants at higher floors more accessible and economically sustainable. The Hysan Place s green roof has been transformed into an urban farm for use by the community for the growth of organic vegetable and herbs. In partnership 7

395 with local non-profit organisations, this urban farm has become an education platform for young people to learn more about organic farming and develop greater awareness of a balance lifestyle and organic living. The social benefit brought about by the urban farm is priceless. 8

396 DESIGN AND OPERATION OF A LEED PLATINUM RATED BOTTLING PLANT IN CHINA SWIRE COCA-COLA LUOHE Samuel Kwong 1, Group EHS Manager John Swire & Sons (HK) Ltd, Hong Kong Simon Yip, Executive Director Corporate Culture & Sustainability, Swire Beverages, Hong Kong Jianwei Ou, Group Manager Production & Facility, Swire Beverages, Hong Kong Scholastica Tsoi, Health & Safety Manager Sustainability, Swire Beverages, Hong Kong 1 Samuel Kwong samuelkwong@jsshk.com, Tel: (852) , Fax: (852)

397 DESIGN AND OPERATION OF A LEED PLATINUM RATED BOTTLING PLANT IN CHINA SWIRE COCA-COLA LUOHE ABSTRACT In 2010, the first Coca-Cola bottling plant in China designed to the Leadership in Energy and Environmental Design Platinum standard was officially in operation at Luohe, Henan province. The plant has a floor area of 166,000 m 2 with an annual capacity of more than 100 million unit cases serving not only the demand of Henan s 100 million populations but also part of Shaanxi, north of Jiangsu and Anhui provinces. It employs over 49 sustainability elements and is estimated to reduce 1,200-1,500 metric tonnes of GHG emissions per year and 21,600,000 litres per year of water comparing with conventional design. The key sustainability measures employed include a ground source heat pump system which provides space air conditioning and heat & cold for production; thermal wall insulation that reduces heat loss; efficient lighting through skylights, induction lighting, LED and T5; bloc filling line which allows ambient filling that eliminates usage of conventional pre-chilling during filling and subsequent warming of the products; renewable energy through solar panel and wastewater biogas for hot water production. Wastewater discharged from the water treatment system is recovered and completely reused, saving 25 million litres of raw water a year. As part of the site selection process, a source vulnerability assessment was conducted to ensure that no adverse water impact could be generated from the operation of the plant and subsequently a source water protection plan was draw-up to ensure sustainability of the water supply to the plant and to the community. The Luohe project is divided in three stages with stage one in operation for more two years and second and third stages to be completed by This paper will elaborate the challenges encountered during the design stage and evaluate the performance of the plant against the design criteria during operational. Keywords: BEVERAGES; BOTTLING; DESIGN; LEED; OPERATION; SUSTAINABLE. 1. INTRODUCTION Swire Beverages is the principal holding company of Swire Pacific s Beverage Division and has the right to produce, market and distribute The Coca-Cola Company s products in Hong Kong, seven provinces in Mainland China, Taiwan and territories across 11 states in Western USA. Swire s partnership with Coca-Cola began in 1965 and has grown to include 16 bottling facilities with over two million square feet of production premises. Swire Beverages covers a total population of 440 million through 18,000 employees, serving over 800,000 customers who sell beverages to consumers. By producing beverages locally, the business aims to bring economic benefits to the local community in the form of investments, job opportunities and taxes, while amplifying this influence through the partnerships with the customers and suppliers for mutual business growth and supporting local development. 2. SWIRE COCA-COLA LUOHE Swire Beverages celebrated the opening of its most environmental efficient plant to date at Luohe, Henan province in October The plant is certified to Platinum rating of the Leadership in Energy and Environmental Design (LEED), an internationally recognized green building certification system. The plant has a floor 2

398 area of 166,000 m 2 with an annual capacity of more than 100 million unit cases serving not only the demand of Henan s 100 million populations but also part of Shaanxi, north of Jiangsu and Anhui provinces. Figure 1: Key Design Features of Swire Coca-Cola Luohe 3. KEY DESIGN FEATURES The Luohe plant employs over 49 sustainability elements and is estimated to reduce 1,200-1,500 metric tonnes of GHG emissions per year and 21,600,000 litres per year of water comparing with conventional design. Chief among these are ground source heat pump; thermal insulation; lighting efficiency; bloc filling line; methane gas for power and water savings PRODUCTION ENERGY EFFICIENCY ADVANCED PRODUCTION EQUIPMENT AND PROCESS The plant has installed with a high speed production line which comes with eco-driven conveying system. Integrated into the design of bloc filling line, bottle rinser and air conveyor system between filler and blower can be eliminated. It also enables ambient temperature filling at 20 o C that eliminates usage of conventional ammonia compressor for chill-filling and subsequent warming process that brings filled product to room temperature before packaging. Raw materials come in at room temperature and products come out also at room temperature but significant amount of energy is used for heating and cooling during production. Potentials are identified to recover the waste heat from cooling process and apply it for heating. For example, hot blast generated from PET bottles blowing process is recovered for ambient heating in the packaging workshop at winter. The plant has also adopted an advanced ambient sugar dissolving system which requires heating only to 85 o C for pasteurisation with excess heat being recovered. A combination of these methods reduces the energy consumption of the plant by 1.7M kwh per year comparing with conventional designs. 3

399 METHANE GAS RECOVERY AND REUSE The plant is equipped with a wastewater treatment facility to ensure the discharge can be returned to the nature safely. Methane gas generated from the treatment process is conventionally flared. This is, however, recovered in Luohe plant to power a smallsized boiler for steam production, which is then used during production, lessening the need for non-renewable energy sources. Figure 2: Methane Gas Boiler GROUND SOURCE HEAT PUMP The earth s temperature below five meters is normally a consistent 15 o C. During summer months, when the earth s temperature is cooler than the air temperature, cold energy is extracted from the earth; while in winter months, heat energy is extracted by circulating water through over 120 kilometers of high density polyethylene piping; which is compiled in a matrix of 800 interconnected vertical boreholes of 50 meter depth underground. The heat pump system provides space heating and cooling to the facility, hot and cold water to the bottling lines and heating to the on-site wastewater treatment facility to improve treatment efficiency. Carbon savings are estimated to range from 20% (cooling) to 40% (heating). 4

400 Figure 3: Ground Source Heat Pump (installation) 3.2. BUILDING ENERGY EFFICIENCY PREVENTION OF HEAT LOSS Heat loss is reduced to a minimum using a combination of methods. The walls of plant buildings are all made from heat insulation materials which insulate heat outside effectively. The building windows are low-e glass which does not only allows natural lighting but also has a two-way energy efficiency ability that prevents heat entering in summer and heat releasing in winter. Approximately, 75% of the workshop roofs are highly reflective, with solar reflectance index of at least 78. Such roofs can effectively reject the solar heat in summer so as to reduce the power consumption of air conditioners. The heat loss prevention methods help reduce the energy consumption by 0.06M kwh per year LIGHTING The plant has a total surface area of 480 m 2 reinforced translucent fibreglass roof panels and 52 tubular skylights, which can supply natural light up to 75% of the total production area. A total of 629 units of induction lights were installed in the production and warehousing areas and 232 units of T5 energy saving tubes in the office area. Street lamps in front of the office building are all powered by wind & solar. These measures help cut the energy consumption by 0.2M kwh per year and save 180 tons of carbon emissions to the atmosphere. 5

401 Figure 3: Energy Efficient Light Fittings 3.3. WATER SAVINGS The plant has installed with a multi-layered water treatment system to process the incoming water from the main before production use. The discharge from the water treatment, mainly the reject from reverse osmosis process, is recovered, properly treated and completely reused, saving 25 million litres of raw water a year. Supply water pipe system is made of HDPE which is rigid and highly resistant to corrosion and can lessen the potential for water leakage due to loading impact and corrosion. This helps improve water use efficiency SITE SELECTION AND CONSTRUCTION During site selection, priority is given to potential sites with access to public transportation to reduce the transportation needs for commuting to and from work. A source water vulnerability assessment study has also been conducted to understand the water demand and supply in the area and ensure no negative water stress will be created to the local community during operation. During construction, measures have been taken to minimise the secondary impacts of the project. The measures include balancing cut and fill, recycling of construction materials, proper disposal of wastes and covering bare soil surfaces sprayed. A waste management plan is drawn up with the construction contractor to ensure a minimum 75% recycling rate of construction materials e.g. concrete, steel, brick, wood and glass, etc. 6

402 Figure 4: Temporary Cover at Fill Bank Recycled materials or construction materials with recycled content are used as possible. At least 20% of the construction materials are sourced from 800 km of the site to reduce transportation and encourage local business. Timber from certified sources is used in at least 50% of the materials in the offices. 4. OPERATIONAL PERFORMANCE REVIEW AND PLAN With over two consecutive years of full scale operation, the sustainability elements incorporated into the design have demonstrated to be effective. The energy and water usage ratios are 0.17 MJ per litre of production and 1.59 litre per litre of production which are 26% and 0.6% respectively better than the company s average in Mainland China. This is the first time the company has applied the LEED standard at its manufacturing facilities and will consider applying the same or equivalent standards on its future development and project. 5. REFERENCES Swire Beverages, 2010 Sustainable Development Report In Essence. from: Available Swire Pacific, 2012 Annual report. Available from: 7

403 A SUSTAINABLE APPROACH TO LARGE-SCALE INTEGRATED DEVELOPMENT TEN PRINCIPLES FOR A SUSTAINABLE APPROACH TO NEW DEVELOPMENT CASE STUDY: TAI KOK TSUI Dr. Sujata S. Govada Council of Architecture, India - Lifetime Member Urban Land Institute (ULI) - Global Trustee + Executive Council Member American Planning Association (APA) Full Member, Past Vice Chair (Special Projects) American Institute of Certified Planners (AICP) - Full Member Hong Kong Institute of Planners (HKIP) - Full Member Hong Kong Institute of Urban Design (HKIUD) - Founding + Full Member American Institute of Architects (AIA) - Associate Member Address: Urban Design & Planning Consultants Limited (UDP International) Suite 9B, Queen s Centre, 58 Queen s Road East, Wan Chai, Hong Kong sujata.govada@udpcltd.com Mr. Stephen Law BA economics MA urban design Bartlett School of Graduate Studies UCL - Doctoral Candidate UCL - Research Assistant Space Syntax Limited, UK - Associate 21 Brownlow Mews, London, WC1N 2LG, United Kingdom stephenlawdesign@gmail.com

404 A SUSTAINABLE APPROACH TO LARGE-SCALE INTEGRATED DEVELOPMENT TEN PRINCIPLES FOR A SUSTAINABLE APPROACH TO NEW DEVELOPMENT CASE STUDY: TAI KOK TSUI Abstract Over the past few decades, Hong Kong s land development projects have grown ever larger in scale, resulting in a podium building typology, covering sites with areas ranging from 10 to 30 ha. While commercially successful, these large-scale developments are typically transit oriented developments (TODs) and are well connected at upper levels with, convenient footbridge networks and offer efficient linkages to mass transit; often resulting in isolated development at ground level and sterilised streetscapes. This paper utilizes the ULI Ten Principles for a Sustainable Approach to New Development and Space Syntax to analyse and assess Tai Kok Tsui. Key findings are highlighted along with benchmarking regional and international case studies conclude with lessons for Hong Kong. Ways to improve the current regulatory framework, planning and development practice are suggested to allow for a more sustainable approach to new development to ensure more integrated large-scale developments to shape a more livable, walkable and sustainable Hong Kong. 1. ULI TEN PRINCIPLES FOR A SUSTAINABLE APPROACH TO NEW DEVELOPMENT In June 2011, the Urban Land Institute (ULI) published the Ten Principles for a Sustainable Approach to New Development Towards Sustainable and Integrated Large-Scale Developments for a More Livable Hong Kong. These ULI Ten Principles (please see the link below) are well received as they highlight key issues related to new development and provide practical and relevant guidelines intended to have a positive influence on future of new large-scale developments in Hong Kong and the region. Using a collaborative process, the Principles were developed and benchmarked against some local, regional and international case studies. They focus on how largescale development can be more integrated and less isolated from their immediate surroundings. The Principles encourage more integrated developments of appropriate scale with accessible public space, adding long-term value to the district and the city by improving the quality of life of people. The ULI Ten Principles to ensure integrated large-scale developments for Hong Kong are: 1) Build on Your strengths: Rethink the strategic vision and policy framework; 2) Create Great Places; Adopt a place-making approach; 3) Extend the Urban Grid; Develop to an appropriate scale and density; 4) Open up Public Space: Provide accessible public open space; 5) Integrate Infrastructure: Ensure transport and infrastructure integration; 6) Activate the Streets: Enhance street level interface and continuity; 7) Keep it Flexible: Facilitate good urban design and flexible zoning; 8) Promote Sustainability; Go beyond sustainable building design; 9) Engage People Early On: Enable upfront public engagement; and 10) Manage, Control and Coordinate: Implement coordinated management control. The following gives an assessment of Tai Kok Tsui using the ULI 10 Principles further supported by analysis using Space Syntax. ULI 10 Principles:

405 2. CASE STUDY: TAI KOK TSUI Tai Kok Tsui is the former home of the Cosmopolitan Dock, oil depots and various industrial uses. Tai Kok Tsui sits between the hustle and bustle of some of Hong Kong s most densely populated residential areas and popular tourist areas. Tai Kok Tsui is a neighbourhood in transition, and is undergoing a major transformation with a large number of urban renewal development areas mainly along the waterfront (Figure 1). New podium developments such as Olympian City over Olympic MTR station, consists of a shopping and commercial development with accompanying residential towers, restricts ground level access to the majority of the older urban area of Tai Kok Tsui and its residents. These new developments consist of towers typically reaching a height of almost 60 stories, surrounded by old low- to mid-rise buildings, not only hindering physical access, but also hampering visual permeability as well. This section uses the ULI Ten Principles for a Sustainable Approach to New Development to assess the newer developments of Tai Kok Tsui (Figure 2). Space Syntax was also used to assess the Tai Kok Tsui area to highlight the contrast between the new and the older areas. In order to study the spatial accessibility and cognition of the study area, the techniques and methods of space syntax analysis have been employed. Space syntax applies methods in graph theory to study the configuration of spatial networks in cities; it is based on research by Bill Hillier and Julienne Hanson at the University College London (Hillier and Hanson, 1984). An important aspect of space syntax is theorising the relationship between space and movement. In transport studies, space syntax measures were shown empirically to relate strongly to pedestrian flows and vehicular flows. (Hillier and Iida, 2005) Key questions asked during the analysis and assessment include the following: 1. Are the routes between Mongkok, and development such as Olympian City and the Waterfront locally accessible as a pedestrian? 2. What are the spatial characteristics when comparing the traditional city and the newer developments closer to the waterfront? 3. Is the TKT waterfront and Mongkok district visually and physically accessible from TKT? 4. What are the main causes of severance between the two districts and its implications on the users of these districts? Figure 1: Viewing Tai Kok Tsui From Mongkok Figure 2: Tai Kok Tsui study area 2.1 BUILD ON YOUR STRENGTHS: RETHINK THE STRATEGIC VISION AND POLICY FRAMEWORK (PRINCIPLE 1)

406 TKT s newer developments highlight Hong Kong s current practice of isolated largescale commercial and residential developments, which has resulted in developments such as Olympian City, a large mixed use podium structure with retail, commercial and residential uses. The presence of these large complexes that are isolated not only block views and tower over the older and low-rise buildings in the area, they often have poor street level interface and lack usable open space at ground level. Originally composed of small grid systems, TKT with its industrial and residential buildings alongside each other, with dynamic neighbourhoods and continuous, vibrant street stalls and shops etc. have characterized this older area. Within a 200 m buffer, the total street length for Mongkok district equates to 4700 m with a total of 64 street segments. In contrast, within a 200m buffer, the total street length for Mongkok district equates to 1700 m with a total of 8 street segments (Figure 3). These neighbourhoods are becoming increasingly scarce and at the risk of being overtaken by new isolated podium developments, which often create a wall at street level, allowing minimal urban design interest and cultural interaction, although internally sound, and commercially viable. The new large-scale developments have not built on TKT s strengths, and also lack good integration to the old urban fabric. 2.2 CREATE GREAT PLACES: ADOPT A PLACE-MAKING APPROACH (PRINCIPLE 2) Many newly created open spaces on the large-scale private developments in TKT are situated on podium, that is privatized. There is lack of high quality public space that is accessible at the ground level. For the public space of Olympian City, although there is a large LED screen, no place-making or urban design suggestions have been adopted like landscaping, attractive street furniture, shading/coverings and public art integrated with public space to create a vibrant and well-used public space for people local businesses. (Figure 4). Figure 3: Tai Kok Tsui Urban Geometry Figure 4: Public space of Olympian City 2.3 EXTEND THE URBAN GRID: DEVELOP TO AN APPROPRIATE SCALE AND DENSITY (PRINCIPLE 3) TKT s land use is a mixture of old and decaying tenement houses, factories and warehouses found mainly in the eastern portion, versus the modern residential developments found across the West Kowloon highway and closer to the harbour. The new developments tend to create a disappearing urban grid phenomenon, not only in the western portion of the area, extending into the hinterland as well. The leading cause of concern in the eastern portion of TKT lays in the contrast between the fine-

407 grain blocks of old TKT and the newer coarse-grain blocks, which accommodate the larger residential complexes. For example Olympian City Phases I and II are situated on the waterfront, hindering waterfront access for residents of the older areas in the hinterland. Highways and a railway also bar waterfront access, compounded with this negative effect of the newer isolated developments. The urban grain analysis describes urban block size distribution, where the size of urban blocks has an important effect on pedestrian activity patterns. Smaller blocks in highly accessible areas increase street activity more retail space potential, allows greater permeability and offers economic opportunity and livelihood for all cross sections of society. Study of the urban grain (Figure 5) shows that the large block size of newer developments such as Olympian City coupled with the lack of active street frontages and large motorway severance hinders inter-neighbourhood movement. The fine grain urban blocks of the traditional area and the presence of active frontages and balance between different transit modes support inter-neighbourhood movement. Figure 5: Urban Grain 2.4 OPEN UP PUBLIC SPACE: PROVIDE ACCESSIBLE PUBLIC OPEN SPACE (PRINCIPLE 4) Major open spaces of large-scale development in TKT are on podium which tend to be physically and visually less accessible such as the privatized open space of the private development The Hermitage (Figure 6). Another example is a playground situated on podium of Olympian City. Less people use the playground due to inconspicuous access from the shopping mall to the playground (Figure 7), the staircase of the access without universal design like sideway for people with baby trolley, the disabled and the old. The accessibility is low and not pedestrian friendly. Figure 6: Privatized open space of The Hermitage Figure 7: access to to the playground without universal design

408 2.5 INTEGRATED INFRASTRUCTURE : ENSURE TRANSPORT AND INFRASTRUCTURE INTEGRATION (PRINCIPLE 5) The presence of the large scale developments along waterfront area of TKT such as Olympian City not only block views and tower over the older and low rise buildings in the area, and often have poor street level interface. Furthermore, the Olympian City area and TKT s lower class hinterland are divided by numerous highways and the airport express railway tracks, rendering the two places inaccessible to each other, demonstrating a most stark example of physical and cultural separation between the two sides of TKT. TKT is entangled in highways and the Airport Express tracks, with the broadest stretch lying between the old fabric and Olympian City 1 (Figure 8). The Western Harbour Crossing forms a barrier, is very vehicle dominant and is not pedestrian friendly. As the raised walkways are the only way to cross between the old and new areas of TKT, poor pedestrian connectivity at ground level cause the public transport interchange (PTI) of Olympian City to be underused, becoming a wasted space. (Figure 9). Figure 8: Poor pedestrian connectivity at ground Figure 9: Poor street level interface will l level between the old and new areas cause underuse of PTI 2.6 ACTIVATE THE STREETS: ENHANCE STREET LEVEL INTERFACE AND CONTINUITY (PRINCIPLE 6) For the residents of the area the shopping malls within are convenient as the Mongkok market is less accessible for shopping. The highway overpasses (especially Tong Mi Road) have few pedestrian crossways, making it difficult to access Mongkok and other parts of Kowloon. Within the TKT area, the three different street grid arrangements (from different time periods) make navigation confusing especially for those unfamiliar with the area. Moreover, the large-scale developments like The Hermitage, Olympian City and Island Harbourview with blank wall design cause poor street level interface and continuity. Space syntax accessibility measures (Freeman, 1977 via Hillier and Iida, 2005) how often a street segment will be part of a route from all spaces within a network at both global scale and local scale. Global accessibility measures how often a street segment will be a part of a route from all spaces within vehicular distance, whilst local accessibility measures how often a street segment will be part of a route within walking distance. A Space Syntax accessibility model has been constructed for the study area. (Law and Zhao, 2009) The analysis suggests low local accessibility potential in the study area (Figure 10) resulting in low walkability, poor legibility and isolated movement near transport node. The highly accessible Argyle Street represents an opportunity to improve accessibility and connectivity towards TKT and the waterfront. Nathan Road and Argyle Street are highly accessibility at both a pedestrian scale and vehicular scale. This integration of scales and different modes of movement benefits informal social interaction and economic transactions between the different users of the city. In comparison, The West Kowloon Expressway is highly accessible at a vehicular scale (Figure 11), but highly inaccessible at a pedestrian scale. This

409 expressway allows for high speed movement at a vehicular scale but acts as a barrier for pedestrian movement and as a severance between the urban area and the waterfront The walking distance between Olympian City 2 and Langham Place is 7-10mins. However, the lack of active frontages, large motorway pedestrian severance and the lack of legible routes, hinders access and interactions between the two districts. Moreover, The waterfront is within close proximity to Olympian City 2 illustrated in the crow-fly distance but physically inaccessible illustrated through the network distance resulting in no physical interactions to the waterfront for residents. (Figure 12). Figure 10: Local Accessibility of TKT Figure 11: Global Accessibility of TKT Figure 12: Global Accessibility of TKT 2.7 K EEP I T F LEXIBLE : F ACILITATE G OOD U RBAN D ESIGN AND F LEXIBLE Z ONING (P RINCIPLE 7) The poor street level integration and blank wall design of the large scale developments in TKT is evidence of the lack of a good urban design plan. Although the newer developments in TKT are commercially very successful do not add vibrancy at street level and city life. The success of new developments should be measured not only their commercially viability but also the social and environmental sustainability and long term value they add to the neighbourhood, district and city. There is a need for good urban design; district based planning and flexible zoning to produce 3-D urban design plans. Regulations such as 100% site coverage resulting in open space limited to the podium level create a pedestrian unfriendly environment at ground level should be carefully assessed. Also by allowing larger road footprints and

410 allowing streets to become wider more like barriers rather than paths will also dictate the type of developments that occur with the residential, commercial and CDA zones. 2.8 P ROMOTE S USTAINABILITY : G O B EYOND S USTAINABLE B UILDING D ESIGN (P RINCIPLE 8) Although some of these large-scale developments may be sustainable at a building level they have done little to incorporate sustainability at a neighbourhood and district level or urban scale; developments such as The Hermitage and the Olympian City have poor physical and social integration with the surrounding areas such as well as no public space at the ground level to integrate with surrounding area (Figure 13 & Figure 14). Having sustainable and certified buildings following HKBEAM and LEED certifications but promoting sustainability beyond buildings, at the urban scale becomes vital for the health of the people and the city. Figure 13: No integration of The Hermitage to the Cherry Street Park nearby Figure 14: No public space to facilitate social sustainability 2.9 E NGAGE P EOPLE E ARLY ON : E NABLE U PFRONT P UBLIC E NGAGEMENT (P RINCIPLE 9) Public engagement happens in Hong Kong but the process needs to be further improved and continued to ensure that newer developments add long term value to the district and the city, improving the quality of life of people. It is not clear how much community engagement actually happened prior to the new developments in TKT. By gauging the outcome of the process one can say the approach adopted was focused on short term commercial gain at the cost of long term value to the community, the city and the people of TKT. Going forward Government, community and the developers should work together early on and keep the process transparent to ensure that the end result is a win-win situation for all. By adopting a district-based community planning approach to engage different stakeholders and the community at an early stage issues related to newer developments can be resolved. Keeping the participation process transparent and inclusive, Hong Kong can promote a better integration of large-scale new developments to surrounding areas at street level and thereby increasing permeability and social interaction as well M ANAGE, C ONTROL, AND C OORDINATE : I MPLEMENT COORDINATED MANAGEMENT C ONTROL (P RINCIPLE 10)