Sustainability of earth building materials - Environmental product declarations as an instrument of competition in building material industry

44 Dia27:Sed by Angel A cones, 19/11/2008, used unde CC BY 2.0, modi ica ion: cu , sou ce:h ps://www. lick .com/pho os/ eddy- click-boy/3043533273/in/album-72157608339140317/ Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 0 45 ABSTRACT Sus ainabili y o ea h building ma e ials – En i onmen al p oduc decla a ions as an ins umen o compe i ion in building ma e ial indus y Ho s Sch oede 1, Man ed Lemke1 1Dach e band Lehm e.V. DVL, Weima , Ge many The e alua ion o he building p ocess in e ms o hei en i onmen al impac in all li e cycle phases o a building leads o he key p inciple o sus ainable building: he analysis o he li e cycle o he ma e ials used in a building. The goal o his analysis is o educe was e and keep he en i onmen al impac as low as possible by “closing” he cycle. Du ing an in en o y, he en i e li e cycle is assessed. This includes he sou cing and ex ac ing o he aw ma e ial, he use o he aw ma e ial o p oduce building p oduc s, elemen s and s uc u es, he use in inished buildings including emission o pollu an s, decay and main enance, and, inally, he demoli ion o he building and he ecycling o he demoli ion ma e ials. T anspo a ion be ween he indi idual phases as well as p oduc ion- ela ed ma e ial and ene gy lows a e also included in his e alua ion. Se e al Eu opean and na ional no ms and egula ions de ine co e ules and a special ins umen o he e alua ion o he sus ainable quali y o a building p oduc based on a quan i a i e analysis o he li e cycle o he ma e ials used in a building: he En i onmen al P oduc Decla a ion EPD. These documen s a e olun a y s anda ds, commi men s o gua an ees o building p oduc s. They a e p o ided by p oduce s, o ganiza ions and quali y assu ance associa ions in o de o es ablish he “en i onmen al pe o mance” o buildings in he o m o a ce i ica e. Such decla a ions mus ully include all phases o he li e cycle o a p oduc by desc ibing he en i onmen al impac du ing p oduc ion and use as well as possible heal h haza ds o he use s. Un il now, EPDs o ea h building p oduc s do no exis . This pape will gi e cu en in o ma ion abou a p ojec o de eloping EPDs o ea h mo a s and ea h blocks s a ed by he Ge man Dach e band Lehm e.V. (DVL). KEYWORDS Sus ainabili y, en i onmen al impac , building ma e ial indus y h p://dx.doi.o g/10.4995/ i u io-ija s.2015.4474 46 1. SUSTAINABLE BUILDING In he B und land Commission epo o he Uni ed Na ions Wo ld Commission on En i onmen and De elopmen en i led “Ou Common Fu u e” (1987) he e m “sus ainabili y” was i s used o desc ibe a las ing de elopmen o humankind. Sus ainable de elopmen ensu es ha i “mee s he needs o he p esen wi hou comp omising he abili y o u u e gene a ions o mee hei own needs“ (UNO, 1987). The building p ocess always has a mo e o less se e e impac on na u al esou ces and cycles. To apply he e m “sus ainabili y” o cons uc ion means ha in all phases o he li e o a building, and wi h espec o he use s' equi emen s, he use o exis ing esou ces and he en i onmen al impac need o be minimized. T adi ionally, du ing he cons uc ion p ocess, he main assessmen ocused on unc ion and design, s uc u al enginee ing, ma e ial echnology and building p ac ice. Today, he building p ocess is inc easingly seen as an op imiza ion ask whe e use demands and en i onmen al equi emen s by he legisla u e need o be in ha mony. The e o e, he e m “sus ainable de elopmen ” comp ises h ee aspec s which mus be conside ed as equals o e an app op ia ed pe iod o ime (BMVBS, 2011): sȩ ECOLOGY sȩ ECONOMYȩANDȩ sȩ USERȩ DEMANDSȩ SOCIOCULTURALȩ CONCERNSȩ ȩ unc ional quali y / heal h). Addi ionally, all buildings cons uc ed acco ding o he equi emen s o sus ainable building mus mee p ede ined echnical pa ame e s and co esponding quali y le els in e ms o planning and cons uc ion o each o he h ee aspec s. Ecological and economic aspec s a e be e de ined as use demands. Se e al cu en EU- unded esea ch p ojec s a e ocused on he use s age o building ma e ials. They in end o imp o e unc ional quali ies and he impac on heal h o building ma e ials, elemen s and s uc u es by imp o ed mois u e bu e ing p ope ies wi h clay as componen in p e- ab ica ed elemen s (Thomson e al. 2015), educed VOC ( ola ile o ganic compounds) emission and highe ene gy sa ings in use a lowe cos s [www.eco-see.eu, www.h-house- p ojec .eu, www.isobiop ojec .eu. In Ge many, he gene al equi emen s placed on building ma e ials and building elemen s wi h ega d o hei echnical quali y a e egula ed by he Model Building Code o he S a es o he Fede al Republic o Ge many (Mus e bauo dnung ü die Lände de Bundes epublik Deu schland – MBO). Acco ding o he MBO, building p oduc s, ma e ials, elemen s and sys ems a e p oduced o pe manen ins alla ion in s uc u es. “Building p oduc s a e only o be used i he s uc u es hey a e used in, along wi h p ope main enance o e a ime pe iod which is p opo iona e o i s pu pose, mee he equi emen s o his law o a e sui able o hei in ended use based on his law” (MBO, §3.2). The MBO lis s he ollowing aspec s as he main equi emen s o he building ma e ials' and building elemen s' sui abili y o use: sȩ MECHANICALȩSTRENGTHȩANDȩSTABILITY sȩ FIREȩPROTECTION sȩ HYGIENEȩ HEALTHȩ ANDȩ ENVIRONMENTALȩ p o ec ion, sȩ SAFETYȩINȩUSE sȩ SOUNDȩINSULATION sȩ ENERGYȩCONSERVATIONȩANDȩHEATȩINSULATION The Regula ion o he Eu opean Pa liamen and o he Council o “Laying down ha monized Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 0 47 condi ions o he ma ke ing o cons uc ion p oduc s” published in Ma ch 2011 (Eu opäisches Pa lamen ; Ra de Eu opäischen Union, 2011) in oduces an addi ional equi emen : he sus ainable use o na u al esou ces. Acco ding o he egula ion, buildings mus be designed, buil and demolished a e hei use in a manne which acili a es he sus ainable use o na u al esou ces and gua an ees he ollowing: sȩ 4HEȩ BUILDINGȩ ITSȩ BUILDINGȩ MATERIALSȩ ANDȩ building elemen s need o be ecyclable a e demoli ion. sȩ 4HEȩBUILDINGȩMUSTȩBEȩDURABLE sȩ %NVIRONMENTALLYȩ FRIENDLYȩ RAWȩ MATERIALSȩ ANDȩ seconda y building ma e ials mus be used in he cons uc ion o he building. This egula ion also equi es he na ional go e nmen s o he EU o apply p inciples o sus ainable de elopmen o building ac i i ies in hei espec i e coun ies. In o de o es ablish sus ainable de elopmen i is necessa y o explici ly o mula e p o ec ion objec i es ega ding he en i onmen , economy and he use s’ in e es s. Examples o gene al p o ec ion objec i es a e he a oidance o ha m ul subs ances, a educ ion in he use o ene gy as well as land and esou ces, and he p e en ion o was e h ough ma e ial eco e y. Based on he knowledge o cause and e ec ela ionships, ac ion s a egies need o be de i ed om he p o ec ion objec i es. These s a egies should a ge h ee le els: aw and building ma e ials, building cons uc ion, and su oundings (Glücklich, 2005). The e ec s caused by he building p ocess on hese le els need o be desc ibed h ough indica o s and by de ining assessmen s anda ds. S anda ds o he assessmen o he sus ainabili y o buildings in e ms o hei en i onmen al, social and economic quali ies a e speci ied in he DIN EN 15643 g oup o s anda ds. Whe eas he ISO 21929-1 in e na ional s anda d de ines a amewo k o he de elopmen o indica o s and o he compila ion o co e indica o s o buildings, ISO 15392 o mula es gene al p inciples o sus ainable building. 2. THE LIFE CYCLE AND MATERIAL CYCLE OF A BUILDING The e alua ion o he ac ion s a egies desc ibed abo e in e ms o hei en i onmen al impac in all li e cycle phases o a building leads o he key p inciple o sus ainable building: he analysis o he li e cycle o he ma e ials used in a building. The goal o his analysis is o educe was e and keep he en i onmen al impac as low as possible by “closing” he cycle. Du ing an in en o y, he en i e li e cycle is assessed. This includes he sou cing and ex ac ing o he aw ma e ial, he use o he ma e ial o p oduce building p oduc s, elemen s and s uc u es, he use in he inished building including i s indoo en i onmen al p ope ies, he li e span wi h main enance, and, inally, he demoli ion o he building and he ecycling o he demoli ion ma e ials. T anspo a ion be ween he indi idual phases as well as p oduc ion- ela ed ma e ial and ene gy lows a e also included in his e alua ion. When passing h ough each phase o he li e cycle he building ma e ial needs o mee he equi emen s o sus ainable building de ined in Chap e 1. These equi emen s a e desc ibed wi h he help o ele an pa ame e s which a e de e mined h ough s anda dized es ing p ocedu es. Fo example, a building ma e ial needs o ha e adequa e comp essi e s eng h o be sui able o load-bea ing cons uc ion o p oo low VOC ( ola ile o ganic compounds) 48 emission in use acco ding o EN ISO 16000 e .al. Mee ing he es c i e ia ensu es ha he equi ed quali ies o a ce ain li e cycle phase ha e been a ained a e comple ing his s age. Only hen is he building ma e ial o building elemen sui able o use. Figu e 1 shows he li e cycle model o ea h as a building ma e ial (Dach e band Lehm e.V., 2004) (Sch oede , 2016). A e passing h ough each li e cycle phase, he ea hen ma e ial a ains a new quali y: aw soil becomes soil o cons uc ion; cons uc ion soil is p ocessed in o ea h building ma e ials e c. By eusing ecycled ea hen ma e ials he li e cycle becomes sel - sus aining. 3. ENVIRONMENTAL MANAGEMENT AND LIFE CYCLE ASSESSMENT En i onmen al managemen is pa o he managemen sys em o an o ganiza ion. I de elops ac ion s a egies o en i onmen al p o ec ion a he company le el as well as he o icial au ho i y le el in o de o ensu e he en i onmen al compa ibili y o he p oduc s and p ocesses de eloped by he company and i s s a pe o mance. The e m li e cycle assessmen desc ibes he sys ema ic, quan i a i e analysis o he en i onmen al impac o p oduc s h oughou hei li es in he o m o ecological assessmen esul s. He e, “en i onmen al impac ” e e s o he use o esou ces as well as he en i onmen al e ec s o emissions a e e y phase in a p oduc 's li e ime. The esul s o he analysis make i possible o ind measu es o educing he en i onmen al impac o o compa ing di e en p oduc s. The li e cycle assessmen has become a gene ally accep ed me hodological app oach o he quan i a i e e alua ion o he sus ainabili y o building ma e ials and building p oduc s. On a Eu opean le el, he ollowing s anda ds o conduc ing a li e cycle assessmen a e cu en ly a ailable: DIN EN ISO 14040:2009-11 En i onmen al managemen - Li e cycle assessmen - P inciples Figu e 1. Li e cycle o ea h as a building ma e ial (Dach e band Lehm e.V., 2004) (Sch oede , 2016) Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 0 49 and amewo k, DIN EN ISO 14044:2006-10 En i onmen al managemen - Li e cycle assessmen - Requi emen s and guidelines. Acco ding o DIN EN ISO 14040 he li e cycle assessmen consis s o ou phases. These phases co espond o each o he and canno be iewed sepa a ely: sȩ DEFININGȩGOALȩANDȩSCOPE sȩ LIFEȩCYCLEȩINVENTORYȩANALYSIS sȩ IMPACTȩASSESSMENT sȩ INTERPRETATIONȩ 3.1 DEFINING GOAL AND SCOPE A de e mina ion o he goal and scope mus de ine he use and unc ion o a p oduc and i s gene al li e cycle om aw ma e ial sou cing o disposal. Figu e 1 shows his cycle o ea hen ma e ials. In e ms o building ma e ials and building p oduc s, his phase is used o selec and de ine di e en ma e ial and cons uc ion op ions. To acili a e his p ocess, so-called unc ional uni s a e de e mined o se e as a e e ence (such as a quan i y uni o a building ma e ial o a sample building as a p oduc -speci ic size). The esul s o he analysis o he en i onmen al impac can hen e e o hese unc ional uni s. P oduc uni s which a e o be compa ed need o ma ch exac ly in e ms o hei unc ions. Fo example, ende and plas e should be compa ed as kg pe m² co e age and insula ion ma e ial as m³ needed pe W/m2K. A he beginning, he sys em bounda ies need o be de e mined by deciding which indica o s o include in he analysis and which o lea e ou . “F om c adle o ac o y ga e” and “ om c adle o g a e” a e ypical examples o sys em bounda ies. The selec ion o hese indica o s can in luence he esul o he li e cycle assessmen . 3.2 LIFE CYCLE INVENTORY ANALYSIS Du ing he li e cycle in en o y analysis phase he de ined ma e ial and cons uc ion a ia ions wi hin he de e mined sys em bounda ies a e es ablished o he ele an ma e ial and ene gy lows. The li e cycle in en o y analysis con ains in o ma ion on all ele an consump ion o aw ma e ials and ene gy, he kind and quan i y o emissions and ha m ul subs ances and, i applicable, all quan i ies o was e gene a ed h oughou he en i e li e ime o he ma e ials and buildings. This ini ial in o ma ion needs o be ob ained om he manu ac u e . The de e mined ma e ial quan i ies a e linked wi h hei en i onmen al impac du ing he impac assessmen phase. The li e cycle in en o y analysis i sel does no include an e alua ion. Collec ion o he equi ed da a can be e y ime- consuming unless exis ing da abases can be used. P ima y Ene gy In ensi y. The ene gy expendi u e needed o he p oduc ion o building ma e ials including he p oduc ion and anspo a ion o he sou ce ma e ials is an impo an indica o o he selec ion o “ecological” building ma e ials. This ene gy expendi u e is called he “p ima y ene gy in ensi y” (PEI) and is mainly ela ed o he sys em bounda y “ om c adle o ac o y ga e”. When i comes o mee ing ene gy needs, he a ailable ene gy includes enewable (e.g. biomass), inexhaus ible (e.g. sun) and non- enewable (e.g. ossil uels) sou ces. The supply o non- enewable ene gy sou ces is limi ed and hey should, he e o e, be used spa ingly. When de e mining he PEI, he amoun o non- 50 enewable ene gy sou ces is iden i ied. This also makes he PEI a measu emen o he en i onmen al impac “use o ene gy esou ces” ca ego y. Applied o adi ional ea h building, he manual p ocessing o sui able exca a ion ma e ial in o ea h building ma e ials and s uc u es on he building si e was and s ill is he ideal si ua ion as a as he PEI is conce ned. Pa icula ly he ac ha no anspo a ion o he ea h building ma e ial was equi ed esul ed in a PEI o p ac ically ze o. Mode n ea h building, howe e , is la gely mechanized and cha ac e ized by he physical sepa a ion o building ma e ial p oduc ion and p oduc use on he building si e. This au oma ically leads o ene gy consump ion and anspo a ion. Long-dis ance anspo a ion and he esul ing high speci ic ene gy consump ion ha e a nega i e impac on an ecological assessmen o building ma e ials, e.g. in he case o a i icial d ying. Tab. 1 shows he PEI o common modes o anspo acco ding o (Glücklich,2005): Mode o anspo PEI [kWh/ km] Rail 0.43 Passenge ca Wes e n Eu ope 1.43 T uck 40 me ic ons 0.72 T uck 28 me ic ons 1.00 T uck 16 me ic ons 1.45 Van < 3.5 me ic ons 3.10 Ca go ship o e seas 0.04 Ca go ship inland wa e ways 0.27 Table 1. Ene gy use o common modes o anspo In e ms o hei PEI, ea h building ma e ials a e s ill un i aled compa ed o he main con en ional building ma e ials. This is e en ue when addi i es wi h a high embodied ene gy a e used. A selec ion can be seen in Tab. 2 (Umwel bundesam e al., 1982): Building ma e ial PEI [kWh/m3] Ea h 0 – 30 S aw panels 5 Wood, domes ic 300 De i ed imbe p oduc s 800 – 1,500 Fi ed b icks 500 - 900 Cemen 1,700 S anda d conc e e 450 - 500 Sand-lime b icks 350 Shee glass 15,000 S eel 63,000 Aluminum 195,000 Polye hylene PE 7,600 – 13,100 PVC 13,000 Table 2. P ima y ene gy in ensi y o selec ed building ma e ials Cumula i e ene gy demand. The cumula i e ene gy demand encompasses he ene gy demand o a building o e i s en i e li e ime (sys em bounda y “ om c adle o g a e”). Acco ding o VDI guideline 4600: 2012-01 i is es ima ed wi h he help o speci ic assump ions and scena ios. The co esponding en i onmen al impac s a e compa ed o his ene gy demand. F equen ly, he PEI o a building ma e ial o a building echnique is only used o a compa a i e e alua ion. A ealis ic assessmen , howe e , needs o ake all phases in he li e o a building in o conside a ion because he ac ual p oduc ion o a building ma e ial and he cons uc ion o a Vi u io In e na ional jou nal o A chi ec u e Technology and Sus ainabili y Volume 0 51 building ep esen ela i ely sho ime pe iods. The e o e, he ad an age o a “low PEI” o an ea h building ma e ial migh come a he expense o he du abili y o he s uc u e o a highe main enance equi emen . Insula ing ma e ials wi h a highe PEI can o se his “disad an age” by educing he equi ed ene gy o hea ing, he eby lowe ing emissions o he en i e li e ime o he building. In addi ion o he posi i e en i onmen al impac , hese ma e ials can he e o e also o e inancial ad an ages o he owne . As a esul , he de e mina ion o how long a building will be in use becomes an addi ional impo an sys em bounda y which has an e ec on he numbe o equi ed main enance cycles o he building elemen o ma e ial laye s. 3.3 IMPACT ASSESSMENT In his phase, he ma e ial and ene gy lows collec ed du ing he li e cycle in en o y analysis a e e alua ed in e ms o hei en i onmen al impac on he basis o selec ed indica o s and de ined sys em bounda ies: The causes a e compa ed o he impac s. Cu en ly, a numbe o compu e p og ams con aining da abases o ele an alues can be used o calcula ing he impac assessmen . The da a analysis mus be ca ied ou acco ding o de ined s anda ds. The p og ams GaBi (www. gabi-so wa e.com), EcoIn en (www.ecoin en . ch, app ox. 4,500 da a iles) and WECOBIS (www. wecobis.de o he Ge man Fede al Minis y o he En i onmen , Na u e Conse a ion, Building and Nuclea Sa e y) a e examples o commonly used en i onmen al da abases. The la e has been a ailable since Janua y 2015. I is s uc u ed based on he c i e ia o DIN EN 15804 and cu en ly con ains app ox. 1,300 da a iles which also co e ea h plas e , ea h blocks and ammed ea h. 3.4 INTERPRETATION Depending on he speci ic si ua ion, he inal in e p e a ion o he calcula ed esul s can be ca ied ou in di e en ways, such as: sȩ AȩCOMPARISONȩOFȩSUGGESTEDȩDESIGNȩVARIATIONSȩ (p e e ed a ia ion), sȩ ECOLOGICALȩIMPACTȩASSESSMENTȩHAZARDS sȩ IMPACTȩ INȩ RELATIONȩ TOȩ ALREADYȩ EXISTINGȩ en i onmen al pollu ion. Today, li e cycle assessmen s a e indispensable o en i onmen al decision making, o example when ying o de e mine binding egula ions o o de s o magni ude o dec easing CO2 emissions in ele an documen s on an in e na ional le el. En i onmen al goals can only be achie ed i hey a e de ined as guidelines in app op ia e s anda ds and egula ions. This also includes p oduc s anda ds in he ield o building ma e ials. The echnical in o ma ion shee s “Technische Me kblä e 02 – 04” (Dach e band Lehm e.V, Tm 02, 2011), (Dach e band Lehm e.V, Tm 03, 2011) (Dach e band Lehm e.V, Tm 04, 2011) published in 2011 by he Ge man Associa ion o Building wi h Ea h include a p ocedu e o de e mining he CO2-equi alen alue on he basis o DIN EN ISO 14040. App op ia e p ocedu es ha e been included in DIN s anda ds o ea h blocks and ea h mo a s (DIN 18945 – 47) as op ional es s (Appendix A). A li e cycle assessmen equi es a signi ican e o du ing he planning s age as well as he willingness o add sus ainable building concep s o con en ional planning ope a ions. O en, a lack o su icien da a poses a p oblem. Al hough he indica o s men ioned abo e allow o a e y de ailed desc ip ion o ecological impac ca ego ies, he e a e s ill ha m ul en i onmen al e ec s which a e gene ally known bu , so a , ha e 52 no been able o be measu ed quan i a i ely. The e e ence accu acy o co ela ions o indica o s which ha e al eady been de ined also emains ques ionable. Finally, he eliabili y o he li e cycle in en o y da a collec ed in he a ailable en i onmen al da abases mus be examined. This mo e o less limi s he alidi y o each esul . On he o he hand, li e cycle assessmen s a e al eady a sui able ool o checking i seemingly easible, ecologically ounded a gumen s can hold up in eali y. Howe e , he necessa y undamen als and ins umen s need o be imp o ed u he . 3.5 ENVIRONMENTAL PRODUCT DECLARATIONS AND CERTIFICATION OF BUILDINGS The li e cycle analysis acco ding o DIN EN ISO 14040 p o ides sys ema ic and s anda dized da a o eco ding ene gy demands and en i onmen al consump ion as well as hei en i onmen al impac s o e he o al li e cycle o a building. In addi ion, he en i onmen al pe o mance o a building acco ding o he p inciples o sus ainable building comp ises i s echnical quali y, unc ional aspec s, socio-cul u al c i e ia as well as loca ion, e.g. anspo a ion in as uc u e. Finally, cos s a e an impo an conside a ion o he clien . These aspec s exceed a “pu e” li e cycle analysis. Two ins umen s ha e been de eloped o analyzing he en i onmen al pe o mance o a building p oduc : sȩ ENVIRONMENTALȩ LABELSȩ ȩ ENVIRONMENTALȩ decla a ions o manu ac u e s o building p oduc s, sȩ ENVIRONMENTALȩ BUILDINGȩ CERTIFICATESȩ FOR owne s/clien s. En i onmen al P oduc Decla a ions. Cu en ly, h ee ca ego ies o en i onmen al labeling a e a ailable o manu ac u e s o building p oduc s: sȩ 4YPEȩ )ȩ ENVIRONMENTALȩ LABELINGȩ ACCORDINGȩ TOȩ DIN EN ISO 14024 consis s o symbols o logos which ha e been awa ded by ex e nal bodies o ou s anding en i onmen al pe o mance. The eco-labels “Blue Angel” and “na u eplus” a e ypical examples. Se e al ea h building p oduc s ca y he la e (na u e plus, e. W.). sȩ 4YPEȩ))ȩENVIRONMENTALȩLABELINGȩACCORDINGȩTOȩ DIN EN ISO 14021 consis s o en i onmen al decla a ions by he p oduce s hemsel es. This means ha he p oduce s a e esponsible o hei own decla a ions which hey can ha e e i ied by ex e nal bodies. sȩ 4YPEȩ )))ȩ ENVIRONMENTALȩ LABELINGȩ ACCORDINGȩ o DIN EN ISO 14025 consis s o olun a y s anda ds, commi men s o gua an ees o building p oduc s. They a e p o ided by p oduce s, o ganiza ions and quali y assu ance associa ions in o de o es ablish he “en i onmen al pe o mance” o buildings in he o m o a ce i ica e awa ded by ex e nal bodies. This ype o label is known as an En i onmen al P oduc Decla a ion (EPD). The ollowing s anda ds cu en ly exis o he de elopmen o EPDs o building p oduc s: DIN EN 15804 Sus ainabili y o cons uc ion wo ks – En i onmen al p oduc decla a ions – Co e ules o he p oduc ca ego y o cons uc ion p oduc s, DIN EN 15942 Sus ainabili y o cons uc ion wo ks – En i onmen al p oduc decla a ions – Communica ion o ma business- o-business DIN EN ISO 14025 En i onmen al labels and decla a ions – Type III en i onmen al decla a ions – P inciples and p ocedu es, ISO 21930 Sus ainabili y in building cons uc ion