PERFORMANCE INDICATORS FOR INDOOR ENVIRONMENTAL QUALITY IN AIR- CONDITIONED OFFICE BUILDINGS. J. BURNETT and DANIEL W. T. CHAN

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1 CIB World Building Congress, April 200, Wellington, New Zealand Page of PERFORMANCE INDICATORS FOR INDOOR ENVIRONMENTAL QUALITY IN AIR- CONDITIONED OFFICE BUILDINGS J. BURNETT and DANIEL W. T. CHAN Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China ABSTRACT In offices, the quality of the indoor environment, as defined by the physical indicators for thermal comfort, lighting, noise, indoor air quality, etc., is paramount to the maintenance of a productive workplace. Poor quality has a definite negative impact, somewhat defeating the purpose of the building. In Hong Kong s commercial environment high-rise office premises are often part of a building complex housing other types of premises. Offices are sold or leased to multiple tenants. The centralised air-conditioning system together with other building services are the responsibility of owning or managing company, whilst part-owners and tenants generally take care of lighting and small power provisions within their spaces. Tenants may be free to install and modify layouts and fittings within fairly loose tenant fitting-out conditions and guidelines. There is no single performance indicator for indoor environmental quality (IEQ). Even for IEQ components an indication of quality performance may be to satisfy only a majority of building occupants, e.g., indoor air quality criteria seeks only to satisfy some 80% of occupants. In reality, the indoor environment varies between floors and premises, and within floors of the same building. Establishing performance criteria for the various IEQ parameters is not too difficult, but deciding on an assessment method that verifies compliance is much more problematic. The final outcome for IEQ depends on system design, commissioning, operation & maintenance, building management and tenant actions. Indoor conditions vary with season, occupancy levels, and workplace activities. This begs the questions of how, when and where to verify the various IEQ parameters. This paper reviews the approaches either presently adopted or under review, for use in the Hong Kong Building Environmental Assessment Method (HK-BEAM). The scheme, which was started in 996, covers both new and existing air-conditioned office buildings. The developers of the scheme seek to provide the most suitable approach to check IEQ criteria against internationally accepted criteria. To gain acceptance in the marketplace these methods must take account of commissioning methods for new buildings, and the problems of assessing buildings which are already occupied. KEYWORDS Indoor environment; building environmental assessment method, energy effective-indoor environmental quality performance indices, performance grading scale. INTRODUCTION Hong Kong has been and still is an important entreport port for Mainland China. The economy in Hong Kong started to flourish after the Second World War. Hong Kong has successfully grown from a small light industrial city into an important financial centre in the world. The demand for office space has been ever-increasing, as demonstrated by the blooming construction industry since 960s. Hong Kong is a relatively small place of,070 km 2 and the natural land is quite mountainous. Most of the flat land for building development in the city centre by the harbour coast is acquired from reclamation. This encourages the development of high rise buildings. Skyscrapers have gradually

2 CIB World Building Congress, April 200, Wellington, New Zealand Page 2 of formed the silhouette of the horizon since 970s. Therefore, the down-town areas are very compact. Consequential to the flourishing economy and efficient infrastructure, the general environment is relatively noisy and the outdoor air quality has deteriorated particularly in terms of particulate concentration. Furthermore, in Hong Kong, the weather is hot and humid for about eight months in the year. Non-air-conditioning offices cannot stay in business. The configuration of the building and the ventilation system interact with each other to impact on the delivery of an acceptable indoor environmental quality (IEQ). An Anecdote in the Evolution of Building Quality in Hong Kong During 960s, air conditioning systems became a norm of building quality in Hong Kong. Unfortunately, the concept of thermal comfort was not well understood. The cooler indoor air prompted the Chinese in Hong Kong to translate the term air-conditioning system to literally mean cold air system. It has brought about the perception that an air-conditioned space has to be cool. This is demonstrated by the large scale survey results (Chan et al. 998) conducted in,98 work places in high rise buildings in Hong Kong (figure ). Only 25% of the work stations were within the thermal comfort zone (reference to ASHRAE ) and 62% of the work stations were on the cool side. 00%RH 60%RH 5 0% 3.2% Humidity Mixing Ratio (g/kg) % 54.4% 34.9% 0.3% 2.5 o C dew point 0 0% 0% 23 o C ET* 26 o C ET* Operative Temperature ( o C) 0% Figure. Distribution of the indoor climatic measurements on the ANSI/ASHARE Standard summer comfort chart defined in terms of New Effective Temperature (ET*), dew point temperature and Relative Humidity. During the 970s, Hong Kong was influenced by the energy crisis triggered by the oil embargo due to the war in the Middle East. Engineers picked the lowest allowable outdoor air quantity of 2.5 litres/second/person from ASHRAE and ASHRAE Standard which were prevalently used in Hong Kong. The Government led the industry by specifying indoor air temperature to be 25.5 C without advising a corresponding change of dressing code to reduce the clo values. Unfortunately, complaints about indoor environmental quality were often misinterpreted as being about being too warm. Therefore, buildings in Hong Kong have remained inadequately ventilated and cold. In the 980s, engineers in Hong Kong were slow in picking up the concept of healthy building. Instead, building services management systems found their chance to get into buildings. Almost all the prestige buildings were competing for building intelligence. However, application of high

3 CIB World Building Congress, April 200, Wellington, New Zealand Page 3 of technology was not properly backed up by well trained field engineers. Many of these systems became white elephants and most of the building services systems remained manually monitored and controlled. Sustaining of indoor environmental quality was responsive as there existed no protocol suitable for real time assessment of indoor environmental quality. In the past decade, a groundswell of demand for healthy building and efficient building have started to grow. Building energy efficiency, radon and legionnaire s disease were put into the agenda of the Hong Kong Legislative Council. Environmental protection was one of the main topics in the annual Government report since 989 (HKG 993). Design engineers started to use an outdoor air rate of 0 litres/second/person according to ASHRAE and now ASHRAE The Real Estate Developers Association of Hong Kong (REDA) initiated the indexing of building environmental performance in 996. Recently, the Government of the Hong Kong Special Administration Region has encouraged developers toward environmentally friendly buildings by waiving the land costs of those areas used for: (i) broadening public corridors and lift lobbies; (ii) providing floor space for high level gardens; (iii) providing balconies for apartment units; (iv) providing greenery resting spaces; (v) increasing planting areas of buildings; (vi) increasing natural ventilation and lighting quality in public areas; and (vii) improving the air quality in the streets and public circulation areas. At this moment, these benefits apply to residential buildings only. However, the determination of the Hong Kong Government regarding building environmental performance is explicit. It is clear that for air-conditioned offices in future, users will look for environmentally friendly buildings with green building services engineering. Table summarizes the historical movement of building performance. Table. The Historical Quest for Building Quality Decade Issues/Concern Building Performance 960s Sense of coolness Air-conditioned building 970s Energy crisis Energy efficient building 980s Awareness of sick building syndrome and building related illness and Intelligent building application of computer control technology in buildings 990s Concern of sick building syndrome Healthy building and building related illness and environmental impacts 2 st century Global effort for sustainable development Environmentally friendly building and green building services systems HONG KONG BUILDING ENVIRONMENTAL ASSESSMENT METHOD REDA of Hong Kong has the vision of an increasing awareness of the large impact which buildings have on the environment, and the contribution that good building design, operation and maintenance can make to reduce such an impact. They initiated the development of a protocol to index the environmental friendliness in 996. Modelled on the Building Research Establishment s Environmental Assessment Method (BREEAM /93 and BREEAM 4/93), two schemes for airconditioned office buildings have been developed for New Office Designs and Existing Office

4 CIB World Building Congress, April 200, Wellington, New Zealand Page 4 of Buildings (HK-BEAM /96R and HK-BEAM 2/96R). These two Hong Kong Building Environmental Assessment Methods (HK-BEAM) for air-conditioned office buildings provide authoritative guidance to owners and operators in practice which minimize the adverse effect of buildings on the global and local environments, while promoting a healthy indoor environment. Structure and Assessment of the HK-BEAM The building environmental issues are grouped under three main headings: (i) (ii) (iii) global issues and use of resources; local issues; indoor issues. The schemes address issues for which there is good evidence of the environmental problems they cause, and for which effective performance criteria can be defined. Many issues cannot at present be included either because there is insufficient information or the assessment is difficult. The schemes are under periodic review and enhancement to take into account new research findings and technology, obsolete issues, environmental trends and government policies. HK-BEAM defines good practice criteria for a range of environmental issues relating to the design, operation, maintenance and management of office buildings. Credits are awarded where criteria of an issue are satisfied. There are three ways where credits are awarded: (i) HK-BEAM encourages a better-than-average design, operation and maintenance. In principle, simple compliance to legal requirements, codes and standards yields average quality and will not be awarded any credit. However, when it is felt that it takes quite an effort for a true (ii) compliance, credits will be awarded. For non-numerical criteria, credits are awarded where effort is applied to satisfy the pragmatic or strategic actions which are favourable to the built environment. (iii) For numerical criteria, credits are awarded where the design, operation and maintenance can achieve at, or better than, the criteria. These criteria are generated either from statistics of large scale survey in buildings in Hong Kong, or are set from simulation of a large number of scenarios. Criteria for energy consumption and maximum electricity demand are examples. The distribution of number of credits are shown in Table 2. Table 2. Distribution of Credits in HK-BEAM Group New Office Designs Existing Office Buildings Credits available Percentage to Total Credits available Percentage to Total Global 22 37% 29 46% Local 7 29% 2 9% Indoor 20 34% 22 35% Total Global issues in both cases have the highest weighting because of the energy issues. Indoor issues carried about /3 of the total. The tenancy arrangement in an existing air-conditioned building imposes difficulties in assessment. Therefore, building owner-controlled areas and the tenant areas are separately assessed. Every building is unique. Therefore, not every issue listed is applicable to any one building. The final assessment is expressed as a percentage of the total. Credits are awarded where the criteria are satisfied. When these are not satisfied, guidance is given on how performance can be improved. The results of assessment are shown on the HK-BEAM certificate as a grading of Fair, Good, Very Good, or Excellent, based on the percentage of achievement of the total credits applicable. At this

5 CIB World Building Congress, April 200, Wellington, New Zealand Page 5 of moment, not enough buildings have been BEAMed to allow a significant statistical analysis of the building environmental performance of air-conditioned buildings in Hong Kong. Therefore, the guideline of grading the performance resembles the award of honours in an university honour degree programme - as shown in Table 3. Table 3. Classification of Grading of Building Environmental Performance (from Centre for Environmental Technology Ltd.) Grading Percentage Excellent Above 70% Very Good 60% - 69% Good 45% - 59% Fair 30% - 44% Unclassified Below 29% PERFORMANCE INDICATORS FOR INDOOR ENVIRONMENTAL QUALITIES The context of the set of issues can be analysed further to highlight performance in a certain area. It is now obvious that an optimum design between energy consumption in a building and an acceptable indoor environmental quality is the goal for the implementation of building services systems in a building. The energy related issues and indoor environmental quality related issues extracted from the two HK-BEAM schemes are shown in Tables 4 and 5 in the appendix for assessment of new office designs and those for existing office buildings are shown in Tables 6 and 7. It should be noted that while new technology is able to provide an energy efficient operation and acceptable indoor environmental quality at the same time, in most instances these requirements conflict with each other. The analysis of both groups of issues allows the designers to strike an optimum performance. The performance indices are manifested by the percentage of attainment of the number of credits available for both the energy consumption and acceptable indoor environmental quality. A good design and operation is one performing energy effective operation - meaning that energy is efficiently used to produce the best acceptable indoor environment. The building will achieve high scores in both groups of issues. For the moment, the interpretation of the scores closely resembles the grading of the environmental friendliness of the building, except that judgement has to be made on both groups of issues simultaneously. More data are being compiled from the HK-BEAM assessments. The research target is to generate an energy effective-indoor environmental performance scale. CONCLUSION In Hong Kong, the awareness of healthy building came later than to the Western countries - perhaps by a decade or two. However, the Government, the institutions and the building industry have caught up fast. The HK-BEAM schemes, originally based on the BREEAM, are now in step with the worldwide Green Building Challenge. The HK-BEAM schemes have been well received by the private sector and the Government. The Government endorses HK-BEAM as a valuable tool for building environmental assessment. The Hong Kong Housing Department has begun to take the criteria as a norm for the design of the public housing. In October 2000, the oil price was at historical high once more. The Hong Kong building industry faces this challenge by working towards an energy effective design, installation, operation and maintenance for acceptable indoor environmental quality. The performance indices generated from the sub-groups of issues in the HK-BEAM scheme are useful and constructive indicators for energyeffective design and operation. Although still at a preliminary stage, more data are being collected

6 CIB World Building Congress, April 200, Wellington, New Zealand Page 6 of from the HK-BEAM assessment. The energy efficient-indoor environmental quality scale is expected to be an appropriate performance indicator for indoor environmental quality. ACKNOWLEDGEMENTS The development of the Hong Kong Building Environmental Assessment Method is sponsored by the Hong Kong Real Estate Developers Association (REDA). The research results presented in this paper are supported by the Hong Kong Polytechnic University. The two HK-BEAM schemes for air-conditioned office buildings were initiated by REDA, developed through a HK-BEAM Steering Committee with the assistance of the Department of Building Services Engineering, The Hong Kong Polytechnic University (BSE), the Welsh School of Architecture, University of Wales College of Cardiff (WSA), and ECD Energy and Environment Limited, UK. The scheme continues to be developed through the same Steering Committee, assisted by BSE, WSA, and the Centre for Environmental Technology Limited (CET). REFERENCES Bean, A.R. and Bell R.J The CSP index: a practical measure of office lighting quality as perceived by the office workers. Lighting Research and Technology 24(4) Burnett, J., Jones, P.J., Chan, D.W.T. and Yik, W.H.F HK-BEAM /96R: An environmental assessment for new office designs. Centre for Environmental Technology Ltd., Hong Kong. Burnett, J., Jones P.J., Chan, D.W.T. and Yik, W.H.F HK-BEAM 2/96R: An environmental assessment for existing office buildings. Centre for Environmental Technology Ltd., Hong Kong. Chan, D.W.T., Burnett, J., de Dear, R. and Ng, S A large-scale survey of thermal comfort in office premises in Hong Kong. American Society of Heating, Refrigerating and Air-conditioning Engineers Technical Data Bulletin 4() Hong Kong Government The Hong Kong environment: a green challenge for the community. Second review of the 989 White Paper pollution in Hong Kong a time to act. Planning, Environment and Lands Branch, Government Secretariat. Prior, J.J. Ed BREEAM/New Offices Version /93: An environmental assessment for new office designs. Building Research Establishment Report, 2 nd Edition. Prior, J.J. Ed BREEAM/Existing Offices Version 4/93. An environmental assessment for existing office buildings. Building Research Establishment Report.

7 CIB World Building Congress, April 200, Wellington, New Zealand Page 7 of APPENDIX Table 4. Available Credits for the Energy Issues for New Air-conditioned Offices Design. Energy Issues Credit available. Electrical energy consumption a) Energy policy, efficient lighting in areas of owners control. for specifying and confirming installation of energy efficient lighting in areas such as plant rooms, lift lobbies, etc., which are under the control of the Owner/Operator. b) Design for lower acceptable office lighting power density. 3 For designing to an office lighting power density of less than 2 W/m 2 (includes tube and ballast loss) credit. < 8 W/m 2 2 credits. < 5 W/m 2 3 credits. c) Heat recovery from exhaust air. Where heat recovery is provided on the general exhaust from the air-conditioned spaces. c2) Space heating from heat reclaim or no space heating. For providing heat claim on chillers for winter space heating or other hot water requirements, or where there is no provision of winter space heating. d) Lower acceptable air-conditioning equipment electricity load. 7 For air conditioning equipment electricity load of less than 50 kwh/m 2 /year (in office areas) credit. < 40 kwh/m 2 /year 2 credits. < 30 kwh/m 2 /year 3 credits. < 20 kwh/m 2 /year 4 credits. < 0 kwh/m 2 /year 5 credits. < 00 kwh/m 2 /year 6 credits. < 90 kwh/m 2 /year 7 credits. 2. Electricity maximum demand. 3 For demonstrating peak electricity demand will be less than 60 VA/m 2 (in office areas). < 40 VA/m 2. < 20 VA/m 2. SUB-TOTAL 6 (27% of total) Table 5. Available Credits for the IEQ Issues for New Air-conditioned Offices Design. Indoor Environmental Quality Issues Credit available. Biological contamination. For complying with the design recommendations described in the Code of Practice of Prevention of Legionnaires Disease. 2. Indoor Air Quality a) Suitable position of outdoor air intake. For suitable positioning of outdoor air intake and exhaust to minimise pre-contamination, to prevent short-circuiting of exhaust back into air intakes, and to avoid nuisance to neighbours from exhaust discharge(s). b) Design ventilation rate. For designs for which the design ventilation rate is 8 l/s per person or above, AND which specifies smoking will NOT be allowed in the building, or for designs for which the ventilation rate meets ASHRAE or CIBSE recommended ventilation rate for a smoking environment. c) Filter efficiency.

8 CIB World Building Congress, April 200, Wellington, New Zealand Page 8 of For specifying filters for intake air and air handling units with dust spot efficiency > or = 80% and, where areas are served by fan coil units with dust spot efficiency > or = 35%, tested in accordance with ASHRAE Standard or European Standard EN-799:993, or for demonstrating that the filtration system installed shall be capable of maintaining the indoor respirable suspended particulate level below 80 µg/m 3 for 24 hour time weighted average. d) Filtration performance. For specifying filters for recirculating air with dust spot efficiency > or = 80% or otherwise showing that this higher efficiency is not necessary. e) Separate ventilation system for known pollutant sources. For design which include provision for separate ventilated system for areas where significant indoor pollution sources are present, such as print rooms, clinics, beauty parlours, etc. 3. Hazardous material a) Material. Specifying particleboard, fibreboard, and similar composite boards conforming to European Standard EN32-, or alternative equivalent standards, excluding use of treated timber where it is not recommended in any relevant codes and standards, and specifying all preserved timber shall be industrially pre-treated ready for finishing on site. b) Paints. No paints are specified which contain lead, and paint containing volatile organic compounds (VOC) conforms to British Standards relating to solvent. 4. Interior lighting a) Lamps. For Tenant Fitting Out Specification which specifies that: fluorescent and other lamps with modulating (fluctuating) output should be fitted with high-frequency ballasts in all the areas used for office work, and lamps shall have a CIE general colour rendering index 80 or above (i.e. colour rendering groups A or B). b) Lighting quality. Where the Tenant Fitting Out Specifications demonstrates, by calculations for a typical office floor plan and surface finishes, that CIBSE guidelines in respect of maintained illuminance on the working plane, illuminance variation, and limiting glare index are followed. 5. Indoor noise a) External noise. For external noise levels transmitted through the building envelope at or below the following values: Private offices and small conference rooms: 40 db L Aeq,T=8hr or 45 db L Aeq,T=30 min. Large offices: 45 db L Aeq,T=8hr or 50 db L Aeq,T=30 min. b) Air-conditioning system noise. For internal noise levels from air conditioning systems at or below the following values: Private offices and small conference rooms: 40 db L Aeq,T=8 hr or 45 db L Aeq,T=30 min. Large offices: 45 db L Aeq,T=8 hr or 50 db L Aeq,T=30 min. SUB-TOTAL 2 (20%) Table 6. Available Credits for the Energy Issues for Existing Air-conditioned Offices Buildings.. Energy Management Programme Energy Issues a) Energy policy and action plan. For having an energy policy and an action plan, with the responsibility for implementation vested in a senior executive. Credit available

9 CIB World Building Congress, April 200, Wellington, New Zealand Page 9 of b) Energy audit. For having carried out an energy audit of the building within the previous three years. c) Energy monitoring and targets. For an energy monitoring and targeting system which sets targets and quantifies savings, together with an energy efficiency improvement investment budget and suitably trained staff to undertake its implementation. 2. Electrical energy consumption a) Retrofit of system. For having undertaken a retrofit programme in spaces for common activities which are under the control of the Owner/Operator and showing an improvement in efficiency, as demonstrated by calculation of installed power density, of 20%, Alternatively, for the installation of energy efficient lighting in spaces for common activities which are under the control of the Owner/Operator, such that the overall installed lighting power density for these spaces is 5 W/m 2 or less. or 2 b) Lighting power density. 3 For designing to an office lighting power density of less than 20 W/m 2 credit. < 7.5 W/m 2 2 credits. < 5 W/m 2 3 credits. c) Demand lighting control. For Tenant Fitting Out Specifications which specifies the provision of one or more of the following types of lighting control systems: time switching: for example, in office areas which have clear time-table of operation; switches linked to occupancy sensors which switch lights off in the absence of occupants; photo-electric switching or dimming system arranged to maximise the use of daylight. d) Heat recovery from exhaust air. Where heat recovery is provided on the general exhaust from the air-conditioned spaces. d2) Space heating from heat reclaim or none. For providing heat reclaim on chillers for winter space heating or other hot water requirements, or where there is no provision of winter space heating. e) Air-conditioning equipment. 7 For air-conditioning equipment electricity load of less than 50 kwh/m 2 /year credit. < 40 kwh/m 2 /year 2 credits. < 30 kwh/m 2 /year 3 credits. < 20 kwh/m 2 /year 4 credits. < 0 kwh/m 2 /year 5 credits. < 00 kwh/m 2 /year 6 credits. < 90 kwh/m 2 /year 7 credits. 3. Electricity maximum demand. For demonstrating peak electricity demand less than 60 VA/m 2 (in typical office areas) credit. < 40 VA/m 2 2 credits. < 20 VA/m 2 3 credits. 3 SUB-TOTAL 2 (33%) Table 7. Available Credits for IEQ Issues for Existing Air-conditioned Offices Buildings. Indoor Environmental Quality Issues Credit available. Prevention of legionnaire s disease a) HVAC equipment: For complying with the recommendations described in the Code of Practice for the Prevention of Legionnaires Disease that are applicable to indoor HVAC equipment. b) Domestic water system

10 CIB World Building Congress, April 200, Wellington, New Zealand Page 0 of For complying with the recommendations described in the Code of Practice for the Prevention of Legionnaires Disease that are applicable to domestic water systems. 2. Indoor Air Quality a) Suitable position of outdoor air intake. By confirming that the positioning of outdoor air intake(s) and exhaust(s) are such to minimise precontamination, prevent short-circuiting of exhaust back into air intakes, and to avoid nuisance to neighbours from exhaust discharge(s). b) Ventilation rate. For demonstrating: a ventilation rate of 8 l/s per person or above is achieved in office premises in which smoking is not permitted, or the ventilation rate meets ASHRAE or CIBSE recommended ventilation rate for a smoking environment, or through proper measurement that the carbon dioxide level in offices premises with an occupant density equal or greater than the design density is less than 800 parts per million. c) Adequate air distribution. For demonstrating through measurement that the air distribution in the occupied areas of office premises is adequate. d) Filter efficiency. For installing filters for intake air and air handling units with dust spot efficiency > or = 80%, tested in accordance with ASHRAE Standard or European Standard EN-799:993, or for areas mainly served by fan coil systems installing filters with dust spot efficiency > or = 35%, or demonstrating that the filtration system installed shall be capable of maintaining the indoor respirable suspended particulate level below 80 µg/m 3 for 24 hour time weighted average. d2) Filtration performance. For specifying filters for recirculating air with dust spot efficiency > or = 80% or otherwise showing that this higher efficiency is not necessary. e) Separate ventilation system for known pollutant sources. For design which include provision for separate ventilated system for areas where significant indoor pollution sources are present, such as print rooms, etc. 3. Mineral fibres a) Original specification. Where the original building specification specifically excluded the use of asbestos in the building, or For having carried out a professional asbestos survey, keeping written record of the location of all asbestos, and taking appropriate action to deal with all asbestos identified. b) Fibrous conditions. For demonstrating that the following conditions are satisfied: Fibrous duct liners are not used inside the ventilation ducts or equipment, excepting coated or uncoated sound attenuation liners up to 4 m in length, or Fibrous duct liners inside the ventilation ducts or equipment are covered with durable polymer or foil or similar fibre control, and fibre release is confined to the return air ducts, and Uncoated duct liners are not used in supply air ducts. Where no significant quantities of uncontained man-made mineral fibre materials are located in the air handling plant rooms or air plenums. OR For demonstrating through measurements of unoccupied office areas levels of mineral fibres less than,000 fibres/m Radon. For having undertaken a radon survey, and for having taken appropriate action where the levels are shown to exceed 200 Bq/m 3. 2 (total) OR 2

11 CIB World Building Congress, April 200, Wellington, New Zealand Page of 5. Hazardous material a) Timber. For specifying particleboard conforming to British Standard BS 5669 and fibreboard conforming to British Standard BS 42, excluding use of treated timber where it is not recommended in any relevant codes and standards, and specifying all preserved timber shall be industrially pre-treated ready for finishing on site. b) Paints. For use of paints that contain no lead, and paint containing volatile organic compounds (VOC) conforms to British Standards relating to solvent. 6. Interior lighting a) Lamps. For Tenant Fitting Out Specification which specifies that: fluorescent and other lamps with modulating (fluctuating) output should be fitted with high-frequency ballasts in all the areas used for office work, and lamps shall have a CIE general colour rendering index 80 or above (i.e. colour rendering groups A or B). b) Lighting quality. Where the Tenant Fitting Out Specifications demonstrates, by calculations for a typical office floor plan and surface finishes, that CIBSE guidelines in respect of maintained illuminance on the working plane, illuminance variation, and limiting glare index are followed. 7. Indoor Noise. 45 db L Aeq,T=8 hr in private offices, small conference rooms. 50 db L Aeq,T=8 hrs in large offices. SUB-TOTAL 7 (27%)