INTEGRATING LIFE CYCLE ASSESSMENT IN BUILDING ENVIRONMENTAL AND ENERGY CERTIFICATION

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1 INTEGRATING LIFE CYCLE ASSESSMENT IN BUILDING ENVIRONMENTAL AND ENERGY CERTIFICATION Andrea CAMPIOLI Prof. Arch. 1 Monica LAVAGNA Arch. Ph.D. 2 Polytechnic of Milan, Milan, Italy 1 andrea.campioli@polimi.it, 2 monica.lavagna@polimi.it Keywords: environmental indicators, LCA assessment methods, eco-efficiency, environmental product declaration Summary Actually the attention of international policies is focused on energy efficiency and on reduction of emissions during building use phase. To obtain this kind of objectives, passive house and zero energy building are promoted. But it is important to remember that it is really hard to realize a building with zero energy or zero emission during the entire life cycle. Probably, to reduce energy needs during the use phase, it is necessary to improve materials and technologies during construction phase. Energy certification put all the attention on reduction of impacts during use phase: but it is not guarantee that energy efficiency means eco-efficiency. If the real objective is to build sustainable buildings, it is important to verify that the zero energy building is really sustainable and that it really reduces resources consumption and environmental impacts. Energy certification is a first step, to reduce energy consumption and emissions, but if it will be the only kind of verification, it can spread passive house, improving resources consumption and emissions in the first stage (production and construction). Energy certification need to be integrated with life cycle assessment indicators. A possible step is to integrate energy certification in an environmental building certification. But actually, environmental building assessment is often based on qualitative indicators, too subjective. It is necessary to integrate quantitative indicators, based on Life Cycle Assessment results. To integrate Life Cycle Assessment results in an energy certification or in a building environmental certification it is necessary to improve the diffusion of life cycle assessment information. A possible scenario is to take LCA information from Environmental Product Declaration. EPD will be spread from CPD directive as technical information on products. Environmental information will be available as other technical informations, to be used during building environmental assessment. 1. Toward energy efficiency in buildings In an environmental perspective, energy evaluation of buildings service life is important to individualize project s strategies for energy saving and for environmental impacts decreasing. Energy certification of buildings is spread by the need of constructors to sell low energy building (with high costs of construction) and by the need of purchasers to be sure of buying low energy building (with low costs for heating). 1.1 Passive House and zero energy building Researchers and public authorities actually are spread 3 liters house, whose energy consumption for heating is less than 30 kwh/m 2 year, and passivhaus, whose energy consumption for heating is less than 15 kwh/m 2 year. This corresponds to about 10% of energy consumption in a conventional building (that consumes kwh/m 2 year). This experimental houses are a good example of energy efficiency and, apparently, also a good example of eco-efficiency. Ernst Ulrich von Weizsacher, Hunter Lovins and Amory Lovins (1997) tell passivhaus as example of ecoefficiency and of Factor Four : doubling efficiency, halving resources. But in their analysis they are looking only at the use phase, without considering the use of resources and the impacts of the production phase caused by the implementation of materials and technologies necessary to build a passivhaus. While a 3 liters house is characterized to have cm of insulating materials in vertical envelope and 30 cm in horizontal envelope, a passivhaus has cm of insulating materials in vertical envelope and cm of covering insulation, triple glass windows and a mechanical system of ventilation with heat recover. 25

2 In this perspective the research can go on and spread zero energy building, as optimum example of environmental impacts reduction. Probably to design a zero energy building it is necessary to improve more and more materials and technologies use in the construction phase. The question is: is the passivhaus construction model an example of eco-efficiency or just an example of energy efficiency? Is always a strategy for energy efficiency also a strategy for eco-efficiency? What is the role of impacts during the entire life cycle? 1.2 Energy efficiency versus eco-efficiency One of the fundamental objectives of energy saving is the reduction of environmental impacts (above all the production of CO 2 ). The Energy Performance of Building Directive (2001) had as first objective the reductions of CO 2 emissions to obtain the goals of Kyoto Protocol. To decrease CO 2 emissions an important step is to reduce energy consumption of buildings, and to reduce energy consumption an important and simple design strategy is to increase insulation. But the increasing use of insulating materials raises environmental impacts: it is necessary to consider the impacts of the entire life cycle (production and use phase) and to individualize the right level of thermal insulating material for eco-efficiency of buildings. It is not always necessary to build passivhaus standard to obtain an eco-building. Figure 1 Energy efficiency and eco-efficiency: verifying environmental impact with a life cycle approach. Life cycle approach (and assessment) can be a support to building design decision and can be useful to verify environmental benefits of building design strategies to eco-efficiency. A technical solution (for example thermal insulation) can appear to increase benefits positively if we are looking only at energy saving during building service life (more insulation, more energy saving, theoretically at infinity). But if we look at the environmental benefits and damage in the entire building life cycle, with a life cycle assessment approach, we can specify the border line of environmental benefits and eco-efficiency obtainable with a specific technical solution (for example thermal insulation) and define the sustainable use of a specific technical solution in a specific project context. 2. Toward eco-buildings Energy assessment and certification is only a first step on the way of sustainability. To be sure to build an eco-building it is necessary to assess also others performances and relations between the building and the environment. The promotion of building environmental evaluation is a synergy of a lot of stakeholders. Existing building evaluation tools are often spread by the need of constructors to sell building with high quality (and high costs) and by the need of purchasers to be sure of buying building with high quality. The use of environmental tools is often highly recommended by local authorities for new buildings. In Japan a good evaluation results is necessary to get a permit to build the new building. Norwegian legal regulations for public procurement mean that it is mandatory to consider life cycle costs and environmental consequences of purchases in the planning process. In Italy, a good evaluation results is necessary to get a bounty in special public competition for eco-building. Often public authorities spread eco-building with bounty or regulations, but do not specify which environmental aspects should be given priority. Rarely public authorities have enough competences on environment to tell eco-building. 26

3 Designers need methods and tools in the design phase to support choice during the project in an environmental perspective. The use of environmental tools can be a guide for architects towards better building definitions from an environmental perspective. Often architects would like to design eco-building, but they get confused on what is better to do for environment. Rarely architects have enough competences on environment to design eco-building. It is important that scientific researchers, with the agreement of public institution, define guidelines for ecodesign and how tell an eco-building. Currently, in order to evaluate the sustainability of a building the first step is to use qualitative tools based on a check-list and a framework of environmental indicators: urban environment, land use, comfort, indoor air quality, energy efficiency, reuse of building waste, adaptability, durability and maintenance. Building environmental assessment tools are already available, such as LEED, BREEAM, HQE, GBTool, CASBEE and others: this show the work of tools developers and the interest of building practitioners in such tools. 2.2 Environmental indicators To evaluate environmental profile of buildings with existing tools, is necessary to answer to a checklist of environmental indicators, providing some points depending on the levels of performances or on the choices of the project. The points have been defined by experts : the architects will define their eco-building on the predefined solutions inserted in the tools. We can read the tool like a Guidelines on environmental design. But is it possible insert in a tool all environmental solutions? Eco-design cannot be only a correct answer to the environmental indicators of a predefined checklist. But it is necessary to define a list of environmental indicators to evaluate the quality of eco-buildings, to certificate them and to give a bounty to them From qualitative to quantitative: the risks of points and weights Environmental indicators of existing building evaluation tools are often based on simplified methods to evaluate performances. It is better for users, because it is not necessary to have technical and scientific competences to answer, but it is worse for environment, because it is possible to spread wrong solutions. The possible eco-wrong derives from ignoring life cycle approach and from transforming qualitative indicators in quantitative points. Figure 2 Possible eco-wrong of building environmental indicators, from a life cycle point of view. Indicators are not always based on life cycle approach: for example, in GBTool there are indicators asking to quantify greenhouse emissions, acidification emissions and eutrophication emissions (typical synthetic environmental indicators of a life cycle assessment), but considering just the use phase of the building (not the entire life cycle). Indicators not always contain quantitative assessment categories for evaluating performance: this make the evaluation partial and subjective. Environmental indicators are often qualitative, but environmental certification need to convert them in points: but how to transform a qualitative evaluation in a quantitative evaluation to sum? 3. Toward Life Cycle Assessment of buildings Architects would like to get an easy answer to choose materials and technical solutions, from an environmental point of view. Typical question is: is it better, from an environmental point of view, to use concrete, bricks or wood for a wall? There are no typical answer. Design is a complex process with no simple answers. 27

4 When building environmental assessment tools try to give simplified answers for assigning points to ecobuilding, it is often an approximate way for evaluating. Qualitative tools for the environmental assessment of buildings, like GBTool or BREEAM, can not give adapted support to make choice at material and product level. Typical indicators at materials and product level are: natural materials, local materials, renewable materials, recycled materials, certified wood. But these qualitative indicators, without a life cycle assessment on the product and on the use of the product in the building, can be inadequate: the risk is to use a natural material with less durability, or a local material less efficient during service life than an elsewhere material, or a renewable material with high impact during production or a recycled material with high impact in recycling, or certified wood with long transport (and impact to transport). Figure 3 Possible eco-wrong of building environmental indicators, from a life cycle approach. In the first stage of a project architects need a quick answer: the respect of the LCA methodology (applied at the entire building) is too complex and too expensive (in time and costs) to be used during design. If LCA data will be available, probably the use of LCA methodology will be simplified. But database on LCA data of building materials are too generic and with few processes. The request from planners and designers of specific data for materials and products is increasing: environmental data are now necessary like others technical data (on performance, on health, and so on), especially to answer to green procurements calls. 3.1 The role of environmental product declaration of building product A possible help can be given by EPD (Environmental Product Declaration), that can give to architects the environmental profile of building products or materials, with detailed and quantitative information based on indicators of environmental impacts. Consumers, stakeholders, customers and designers are demanding information about the environmental implications of building and construction activities. The problem is that the volume of information needed to provide a comprehensive description of environmental performance is large. The typical results of a life cycle assessment can be interpreted only by a small number of specialist in this field. There is a desire to simplify the results by compressing them assigning a score, or an ecolabel, which essentially says good or bad. This way is not possible in building sector: the environmental data on the products have to be considered as technical information, as performance profile, to put on the table during design decision. Construction Product Directive contain in the list of essential requirement the field of environment. Probably the need of environmental information will be promote by CPD, according with the program of development of EPD in construction sector. Designers are tempted to compare directly products or technical solutions for wall or construction systems, using EPD. But EPD cannot be used comparing them directly; only building can be compared, along their life cycle, if they give the same performance. In building sector, environmental quality of the product does not mean necessary eco-efficiency of the product in the building. Designers need to know performance and environmental profile of a building component, but in building sector eco-efficiency must be evaluated at building level: eco-efficiency of a component has to be assessed by knowing the role of the component in the building and knowing life cycle scenarios of the building itself. For this reason, in building sector it is not enough to have an environmental mark on the product that says: this product is environmental friendly. Designers need to know the environmental profile of the product, like other performance of the product: as data about thermal performance, acoustic performance, resistance performance are available, so it is necessary to have also the environmental profile of a product, as indicator in the moment of the design choice. 28

5 Figure 4 Performance and eco-performance: from the product to the building. EPD can give this kind of information: it is not a mark like Ecolabel (with benchmark), that does not give to the designer environmental information; EPD is a document with an environmental profile and specific indicators that can be used in a life cycle assessment. This kind of label is more useful in the building sector, because it gives information that can be used in an environmental assessment at building level The use of EPD in building environmental assessment EPD can give information on material and product level, but the information on impacts contained in an EPD (global warming, acidification, eutrophication, stratospheric ozone depletion, photochemical ozone creation) can not be simply used. It is important to understand which is the best product from an environmental point of view, but it is not simple. Comparing EPD directly is not possible in building design: it is necessary to know the use of the component in the building and the performance needed from the component put in the building. How can designers compare a products without defining first a correct functional unit? Figure 5 Comparing products directly can be difficult: it is necessary before to define the functional unit. If we compare EPD assuming as functional unit one performance, for example thermal transmission, it can be incorrect (if the role of the component will be also to satisfy other performances, for example acoustic performance). So we can compare EPD only when we know the role of the component in the building, assuming as functional unit the performance needed by the building system and the aim for which the designer choices the component. So EPD data of building s products can not be compared without knowing the role of the product in the building and without knowing the kind of building that will be built, its place and context, its use, its life time expected, etc. 29

6 Figure 6 To compare products it is necessary to define the functional unit, based on performances. Environmental data on the products can be compared only related to the service life of the product in the building use. Only on the building level it is possible to know service life scenarios and to define functional unit based on building performance, and so compare products with the same quantity (reference flow) based on a functional unit adequate with the performance required by building phase. Figure 7 Eco-efficiency of the product depend on the role of the product in the building. Every building is different and requires different performance by products: this is the great distance from building design to industrial design. Industrial design production generates a prototype and then identical objects; instead every building is a prototype, every building is a single and new system, with specific problems, needs and features. Figure 8 Environmental profile of the building cannot be the sum of environmental profile of components. 30

7 3.1.2 Life Cycle Assessment of a building LCA application in building sector is not simple because there are two assessment to do: one on the life cycle of the product and one on the life cycle of the building. This means to have environmental profile of the building components to evaluate environmental profile of the building. Figure 9 Relationship between products and building in a life cycle assessment. A complete LCA of a building can be done only with LCA data on the life cycle of the products and components to build it: this kind of data can be obtained by EPD, but have to be integrated with LCA data on the specific building life cycle stages (related to location of the building site, construction technologies, use of the building, energy consumption, maintenance) depending on the decision of the single project (design for energy efficiency, design for disassembling, design for recycling). For example, building performance and technological components choice are very different in a temporary project with the objective of adaptability and flexibility instead of a permanent project with the objective of durability: these aspects are defined during the building project and influence life cycle scenario. If the objective (expected performances) of the service life of the building changes, probably also the best available technologies or the design strategies for eco-efficiency will change The role of durability Peculiarity of building sector is to produce products (buildings) with very long life cycle: it determines the priority of the performance of material and of building components in the evaluation of the environmental compatibility. Figure 10 The role of durability of components and of expected life-time of the building. The durability of components plays a great role in a life cycle assessment, but little information are available on durability of building components. It appears important to avoid abstract comparison between alternative materials, and to spread comparison lowered in the specificity of the single project, where it can emerge the real equality of performance of the products analyzed like synergy of the performance expected from those components, in the specific role inside the building. Probably in a permanent building with the objective of durability and comfort, for eco-efficiency is better to choose components heavy (for thermal mass), durable, easy to maintenance. Probably in a temporary 31

8 building with the objective of adaptability and flexibility for eco-efficiency is better to choose components prefabricated, light, dry assembled (for selective demolition of its components at the end of life-time), removable, adequate for recycling. If the objective of the expected life-time of the building changes, probably also the best available technologies or the design strategies for eco-efficiency will change. 3.2 From product to building: an integrated environmental assessment Environmental assessment of a building cannot be a predetermined check-list of indicators, defined without knowing the building context, without knowing the building use, without knowing the building life-time expected. Environmental assessment of buildings has to be a assessment of environmental impacts of building production and of building use, considering the building life-time expected. MJ/m 2 or CO 2 /m 2 or SO 2 /m 2 can be synthetic indicators to assess eco-efficiency of the building: they can be used for comparing building on the effects of design choice on environment because they quantify environmental impacts of building activities. Figure 11 Synthetic indicators, from Life Cycle Assessment, to assess eco-efficiency of buildings. Energy certification on use phase give synthetic indicators on energy consumption (for example MJ, CO 2 emissions, SO 2 emissions) during the use phase of the building; from these indicators is possible to define the environmental profile of the building during the use phase. The sum of EPD of building products give some synthetic indicators on impacts in the production and construction phase; from these indicators is possible to define the environmental profile of the building during the production phase. From the synergy of these indicators is possible to define the environmental profile of the building during the entire life cycle. Environmental assessment tools based on check-list have an important role: to complete the quality assessment, verifying other indicators on qualitative aspects. LCA approach gives information on environmental profile, but does not verify comfort, indoor air quality, adaptability and flexibility of spaces, quality of light, and so on. LCA approach compare building as quantity of materials, assuming that two buildings have the same performances. The levels of performances guarantee by the compared buildings can be define by building assessment tool. Only a synergic evaluation of the building, considering energy assessment, environmental assessment and LCA assessment, can give information on the real environmental results obtained by strategic solution in an environmental perspective. References Bleischwitz R., Hennicke P., 2004, Ecoefficiency, Regulation and Sustainable Business, Edward Elgar Publishing, Cheltenham. Yeang K., 2006, Ecodesign. A Manual for Ecological Design, Wiley-Academy, Great Britain. SETAC Europe 2006, 13 th LCA Case Study Symposium. Environmental Product Declarations with focus on the building and construction sector, Proceedings, Stuttgart. von Weizsacher E.U., Lovins H., Lovins A., Factor Four: Doubling Wealth, Halving Resource Use, Earthscan, London. 32