There are different ways to assess environmental impacts caused by the building market and there are also different users of assessment methods. This article suggests how different concepts can be developed and applied to evaluate building products and constructions from an environmental point of view. Some crucial issues regarding different life cycle phases are also discussed

Erlandsson, Martin

Lundblad, Dag

English

Nordic Journal of Architectural Research / Nordisk Arkitekturforskning

N O R D I S K AR K I T E K T U R F O R S K N I N G 1 9 9 5 : 1 Environmental Evaluation of Buildings - A Survey of Possibilities and Problems by Martin Erlandsson & Dag Lundblad There are different ways to assess environmen-tal impacts caused by the building market and there are also different users of assessment methods. This article suggests how different concepts can be developed and applied to evaluate building products and constructions from an environmental point of view. Some crucial issues regarding different life cycle phases are also discussed. Dag Lundblad & Martin Erlandsson Department of Building Sciences Royal Institute of Technology, Stockholm N A T U R E I T S E L F can be regarded as self-destructive. T h e n u m b e r o f animal species varies i n cyclic periods and is today decreasing ( W i l s o n , 1989). Erosion and the decomposit ion o f rock occur naturally w i t h or w i t h o u t the i n t e r v e n t i o n o f the h u m a n being. Nature has i n fact adapted to this natu-ral degradation i n different ecological systems (Tiberg , 1993). However, i t should be noted that h u m a n activities do affect the env i ron-m e n t crucially. T h e h u m a n being is the on ly species w h o is able to exterminate himself. H u m a n activities speed up the t ime frame, w h i c h means that nature does n o t have the t i m e to adapt to all new situations. T h e need for env i ronmenta l assessment seems to be a cr i t ical issue for our existence. Environmental goals T h e overall env i ronmenta l goal c o u l d be ex-pressed as fol lows maximize the social benefit o f a resource or a performed service w i t h minor environmen-tal impact. (Erlandsson, 1994.) T h e m a x i m i z a t i o n o f the social benefit i f our actions is dealt w i t h i n the theory o f u t i l i t a r -ianism. I n cr i t i c i sm o f the theory o f u t i l i t a r i a n -ism i t is argued that social benefit is n o t c o m -parable between different indiv idual s , since they experience the same service i n different ways (e. g. Glover, 1977). T h i s means that the max imiza t ion o f the social benefit m e n t i o n e d i n the goal above w i l l be hard to f u l f i l l i n practice. Also, env i ronmenta l impacts may be 39 adaptation optimization" Figure 1 . Assumed result of environmental Improve-ments. hard to assess. Nevertheless, it is often possible to analyze such impacts i n a quantitative or qualitative way. Thus, i t would seem reason-able to modify the goal mentioned above to correspond to a more attainable goal. W i t h the knowledge we have today we can endeavor to minimize the environmental impact of a given social benefit described as utilization of a product (Erlandsson, 1994.) W i t h this new goal i t is consequently not argued i f a product is needed or not - merely how its impact should be reduced. Hence, there is no strict scientific method for com-paring different environmental discharges, nor is it possible to reach a consensus as to how the evaluation should be done in the foreseeable future. Different assessment methods do exist but no single method is generally in use (e. g. Steen et al, 1992; Ahbe et al, 1990; Heijungs et al 1992). Another approach to assessment is based on fundamental ideas of how nature wotks and how the humans adapt to it (Robert, 1993). Examples of such normative environmental principles are given below: • The extraction of resources must be equal to or less than their re-creation; • The less that is produced, the better for the environment; • Commonly, an unfamiliar substance affects nature more than a historically known sub-stance; • A product that can be reused or recycled is normally better than a product made o f virgin raw materials discarded after use. I f the principles mentioned above are put into practice, i t is most likely that a consensus wi l l be reached and also that initial environmental improvements wi l l result. After an initial environmental study of the adaptation phase, reliable improvements are assumed to be possible (figure 1). However, after a number o f improvements have been observed i t is often not so easy to evaluate the consequences of a proposed action. This creates a need for a better environmental ass-essment method than the one based on given environmental goals, as set out above. But even in the future, with a development o f ass-essment methods, it w i l l in practice be i m -possible to achieve a min imum of environ-mental impacts. So we wi l l never acquire the knowledge that enables us to evaluate impacts to that degree. Because environmental data is so uncertain and assessment methods are based on such different assumptions, environ-mental assessment should be treated with caution. Assessment concepts We have recognized that products in general can be subjected to an environmental study, since they have a given social benefit. Life-Cycle Assessment is frequently used by big manufacturing companies to assess products. The concept, Life-Cycle Assessment, L C A , (Swe. livscykelvdrdering), studies a product from cradle-to-grave, or in other words from the earth and back as discharges to any reci-pient. The problem is that the resources used in a product cannot always be described by a cradle-to-grave flow analysis. I n the ecocycle society, discarded products wi l l end up as raw materials for new products and may result in a 40 MARTIN ERLANDSSON & DAG LUNDBLAD cascade o f products f u l l f i l l i n g different func-tions. I f t w o different products are to be c o m -pared as part o f an assessment, their functions have to be the same. I n reality this is often n o t the case. Di f f e rent approaches are applied w h e n the same resources are used i n different products or funct ions . T h i s means that the re-sults f r o m different L C A S o f s imilar products sometimes vary. T h i s p h e n o m e n o n is recog-nized as a system boundary p r o b l e m (Erlands-son, 1993). Therefore, i t has been f o u n d con-venient to d iv ide the life-cycle i n t o lifetimes (figure 2). A demarcat ion l ine is d r a w n between each product w i t h a given f u n c t i o n - a l i fe t ime. Each l i f e t ime describes h o w the produc t is used. I n this concept, called L i fe-Time Assess-ment , L T A , (Stue. livstids-värdering), the pro-duct system boundary is defined by the market (Erlandsson et al, 1994). Since the market de-fines the a l u m i n u m i n an engine i n a car as one p r o d u c t and the same recycled a l u m i n u m i n a n u m b e r o f cans as different types o f products, i t makes n o sense t o ta lk about Product Life-Cycle Assessment. T h e conclusion is that : L i f e - T i m e Assessment, should be used to evaluate products. Life-Cycle Assessment should be used t o study flows of resources. These t w o methodologies have different appro-aches w h i c h c o m p l e m e n t each other. T h e L C A fol lows the use o f resources ( i n one or more products) and ensures sustainability. L C A is de-fined as f o l l o w i n g all resources used f r o m the cradle to the grave. T h i s means that L C A of ten includes more than one product . T h e L T A deals w i t h one produc t only, w h i c h makes i t possible to compare different alternatives that meet the same demands. I n an L T A the subsequent use o f a p r o d u c t does n o t have to be k n o w n , the mere fact tha t i t has another area o f use is enough. T h i s s impl i f i ca t ion is very i m p o r t a n t , especi-ally to long- l ived products where the subse-quent use cannot be accurately predicted. I t should be not i ced that there are a n u m b e r o f Figure 2. Lifetime as a part of a life-cycle (Erlands-son et al, 1994). theoretical and practical problems regarding L C A w h i c h are n o t discussed i n this article. However, whether the concept o f L T A is accep-ted or not , i t is possible to re-calculate the data and add any assumed final use t o create an L C A . Some crucial issues for building components M a n y diff iculties arise w h e n the e n v i r o n m e n -tal impact o f products w i t h l o n g service lives is assessed. A lo t o f env i ronmenta l data for di f-ferent products is missing a l though i n f o r m a -t i o n is available i n the l i terature. Loca t ion o f a b u i l d i n g c o m p o n e n t affects maintenance re-quirements as w e l l as the i n d o o r env i ronment . Thus , i n the future i n v e n t o r y data mus t be related to the applications. Some issues that are o f special interest for b u i l d i n g products are discussed below. Impact during usage phase T h e degradation o f b u i l d i n g products affects the i n d o o r as w e l l as the o u t d o o r e n v i r o n m e n t . T h e interact ion between different materials sometimes causes a lo t o f damage, m a i n l y be-cause o f the close relat ion between h i g h mois-ture content and unsuitable combinat ions o f products . T h e a im o f maintenance is to keep the product i n proper w o r k i n g order so that its service life is pro longed . I n spite o f this p o o r l y executed maintenance has i n some cases short-ened the service life. T h e impacts d u r i n g the usage phase o f a p r o d u c t c o u l d be as i m p o r t a n t ENVIRONMENTAL EVALUATION OF BUILDINGS 41 as its impact during manufacture. One report that supports this view deals wi th the environ-mental effects o f floor maintenance (Lund-blad, 1994). However, adequate data from the usage phase is still missing and mote research is needed. Further, thete is a need for proper methods to assess the impacts of emissions caused by the degradation of products. A n ass-essment project o f this k ind is in progress, in Denmark (Nielsen and Wolkoff, 1993). Sta-tistical data o f the risk of failures during the usage phase should be taken into considera-tion in any assessment of a building product. Service life prediction The service life of a product is directly related to its environmental impact. Where two pro-ducts are equal but one has twice the service life of the other, this product has half the en-vironmental impact. There are few adequate test methods to predict the service life of buil-ding products. A higher degree of accuracy in service life prediction wi l l be possible wi th a better understanding of degradation mecha-nisms and the in-service conditions of buil-ding products. This wi l l perhaps lead to pro-ducts with better durability and fewer negative effects on the environment. Aesthetic aspects also play an important role in predicting the service life of some building products. A poor design or changes of fashion are good reasons for replacing products. A n aesthetically l imi -ting value can arise long before a product's technical service life has reached its end. O n the othet hand, the aesthetic values of a pro-duct wi l l in many cases be detetmined by its technical qualities. It is therefore important that a product's technical performance pre-vents it from (unwanted) "aesthetic aging". I n some cases aging provides the products with a surplus value. This is for instance the case with roofing tiles. Dismantling Compared wi th products that have to be com-busted or put into a landfill, products that can be reused or recycled are often preferable from an environmental point o f view. To fa-cilitate reuse and recycling i t is essential to build for destruction w i t h flexible joints. A technical development o f reused components on its own is not sufficient - there also has to be a market that demands these kinds o f pro-ducts. Conceptual approach for environmental assessment of constructions The issues described in the chapter above have to be implemented in a building product re-lated assessment model. This overall view is absent today. A useful concept is based on the Life-Time Assessment methodology. One sug-gestion is that the quantitative part o f the model takes into account constructional and operational data. A qualitative part o f the ass-essment is to evaluate how different products in a construction are combined. Depending on the application of a product, different kinds of impacts wi l l arise. This means that the func-tion of a product must be evaluated against the environmental effects of use in a specific app-lication. The research work on the building product related assessment method, described above, wi l l bring us a little closer to a model for assessing buildings or other types o f construc-tions. The complexity of environmental assess-ment models of buildings makes great simpli-fications necessary today. A building is for the most patt not a static system but a dynamic system where actions are taken all the time to satisfy new needs. This makes it impossible in reality to make "true" environmental assess-ments since nobody can ptedict what wi l l hap-pen in the future. However, to conduct a conceptual L C A o f a construction in its entirety it wi l l be necessary to take into account the following; all main-tenance, replacing of discharged building com-ponents, operation and service, moderniza-tion and the final demolition phase. A simpli-fication is to study the individual lifetimes of a 42 MARTIN ERLANDSSON & DAG LUNDBLAD cons t ruct ion (figure 3). T h e l i fe t ime w i l l be de-f ined as the t ime f r o m construct ion to moder-niza t ion . I n this case moderniza t ion is con-sidered as an alternative to d i smant l ing the b u i l d i n g and erecting a new construct ion . T h e use o f L T A leads to less unre l i ab i l i ty regarding questions related to the t ime frame. I t should be recognized that energy related screening environmenta l studies have been per-f o r m e d u p o n bui ld ings (e. g. Rauhala, 1992; S B I , 1993). For example, energy flows used for heating, vent i l a t ion , water supply and w a r m water heat ing d u r i n g the service life o f houses w i l l fundamenta l ly affect the environmenta l impact . W i t h all the s impli f icat ions necessary to make an env i ronmenta l assessment o f a b u i l -d i n g , do we really have to assess a whole b u i l -d i n g or is i t enough to l o o k at b u i l d i n g pro-ducts f r o m a overall quanti tat ive perspective ? Whatever assessment m e t h o d is used, the a im must be to achieve a m i n i m u m o f environ-menta l impact . T h e p r o b l e m is that the level o f details decrease, f r o m an assessment at p roduc t level to a whole construct ion, because o f assumptions and s impli f icat ions made o n the way. O n the other h a n d an assessment o f a whole cons t ruct ion gives "soft" i n f o r m a t i o n about condi t ions that are n o t dealt w i t h i n a product assessment ( B R E E A M , 1993). These con-di t ions are, for instance, l and values, access to dayl ight , facilities for sor t ing refuse. B o t h ass-essment methods are required today and the basic research w o r k o n h o w to improve the b u i l d i n g product assessment methodology w i l l hopeful ly lead to better b u i l d i n g assessment methods. Purchasers of assessment models W h o w i l l become users o f env i ronmenta l ass-essment models? Di f ferent groups i n the b u i l -d i n g market w i l l be interested i n new assess-m e n t models. Some o f the b u i l d i n g product manufacturers are already using L C A . T h e de-ve lopment o f existing product assessment Figure 3. LTA and LCA of a construction. methods and software for computers w i l l help b o t h manufac tur ing industries i n p r o d u c t de-velopment and architects and technical con-sultants to choose the r i gh t combinat ions o f materials. I t is most l ike ly that demands for more en-v i r o n m e n t a l l y sound constructions w i l l come f r o m governmental bodies as w e l l as consu-mers. O t h e r interested parties are banks and insurance companies w h o are are a part o f d i f-ferent projects i n v o l v i n g great financial risks. I n the Swedish b u i l d i n g market responsi-b i l i t y for the d e m o l i t i o n o f a cons t ruc t ion w i l l probably lie w i t h the owner (Bl ix , 1994). T h e administrator or owner m i g h t i n this case re-quire a guarantee f r o m the cons t ruc t ion c o m -pany, concerning h o w the d i s m a n t l i n g o f the construct ion can be per formed i n an env i ron-menta l ly sound way. Finally, i t can be stated that a number o f participants i n the construc-t i o n process w i l l have to p e r f o r m different types o f env i ronmenta l assessments. For this reason i t is most i m p o r t a n t to cont inue the development o f assessment models. Martin Erlandsson and Dag Lundblad are research students in building materials at the Department of Building Sciences, Royal Institute of Technology, Stockholm. ENVIRONMENTAL EVALUATION OF BUILDINGS 43 References Ahbe, Stephan et al, 1990, "Methodik fiir oekobilanzen". BUWALm 133, Bern. Blix, Kerstin 1994, The journal V-byggaren, nr 6 "Producentansvar for byggvaror i Sve-rige", pp. 14-15, Stockholm. Building Research Establishment, 1993, Ver-sion 1. B R E E A M An environmental assessment for new office design. Garston. Erlandsson, Mart in , 1994, Life-Time Assess-ment. A develpoment of Life-Cycle Assess-ment. Swedish Reseatch Council, Stock-holm. Erlandsson, Mart in , 1993, Three Different Sys-tem Boundaries in a Life-Cycle Assessment of Wood Products. Roal Institute of Techno-logy, Departement of Building Materials. Stockholm. Erlandsson, Mar t in and Odeen, Kai, 1994, Life- Time part of a Life-Cycle. Roal Institute of Technology, Departement of Building Materials. Stockholm. Glover, Jonathan, 1977, Causing death and saving lives. Pelican Books, England. Heijungs, R., 1992, Environmental life cycle assessment of products. C M L , Leiden. Lundblad, Dag, 1994, Miljöpåverkan av golv-vård— en betydelsedel i golvmattans livscykel. Royal Institute of Technology, Depattment of Building Materials. Stockholm. Nielsen, Peter and Wolkoff, Peter, 1993, Inde-klimamœrkning af byggverer. Del 1: Beskri-velseafen prototypeordning, S B I Rapport 232, Kopenhagen. Rauhala, K , 1992, A model for estimating ener-gy and emission consequences of urban struc-ture. V T T Technical Research centre of Fin-land. Espoo. Robert, Karl-Henrik, 1993, Det nödvändiga ste-get. Affärsförlaget Mediautveckling. Stock-holm. Steen, Bengt och Ryding, Sven-Olof, 1992, The EPS enviro-accounting method, I V L rap-port B 1080, Gothenburg. S B I , 1993, Livscyklus-baseret byggnings-proj ek-tering. SBi-Rapport 224. Statens Byggeforsk-ningsinstitut. Kopenhagen. Tiberg, Nils, 1993, Kretslopp. Naturskyddsför-eningen förlag AB. Stockholm. Wilson, Edward O., 1989, Scientific American, september edition. "Threats to biodiversity". 44 MARTIN ERLANDSSON & DAG LUNDBLAD 

Environmental Evaluation of Building - A Survey of Possibilities and Problems

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Environmental Evaluation of Building - A Survey of Possibilities and Problems

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