A COMPARISON OF THE CLIMATIC EFFECTS OF BUILDINGS

Transcription

1 A COMPARISON OF THE CLIMATIC EFFECTS OF BUILDINGS A review of studies carried out in the 2000s. Matti Kuittinen,

2 CONTENTS Part 1 Background Methods Compared buildings Limits of the work and factors of uncertainty Part 2 Slides Client Rakennustuoteteollisuus ry Wood Product Division Author Matti Kuittinen Architect, Researcher matti.kuittinen@kombi.fi Tel Part 3 Recommendations for further action

3 Part 1 BACKGROUND

4 Objectives This report aims to compare studies carried out in the 2000s, which have calculated the effects of different frame materials on the climatic effects of a building. Here 'climatic effects' means emissions that harmfully accelerate climate change or environmental impacts that indirectly but closely affect it (such as the need for primary energy or resource efficiency). The purpose has been to establish how the results of timber-framed alternatives differ from other frame materials in studies carried out by different researchers. The starting points and aims of studies collected for the purposes of this report have been different from each other, and are not directly comparable. Attempts have therefore not been made to combine results with one another, but to show the general trends of the climatic effects of building materials observed in the different studies. A comparison of building products should only be carried out if they fulfil the same function (EN15804). It has not been possible completely to verify this principle with regard to all the studies collected, because the studies are not usually based on building product environmental specifications accordant with standards, but are by nature scientific. Because of this, this report can only prove the general direction of different study results, and does not take a stand on the superiority of the climatic effects of the different building materials of a specific subject. Subject-specific examinations should always be done taking into account the functional requirements of the subject and the quality of the environmental data of the building products selected for the comparison.

5 Methods Environmental impact assessments for buildings carried out in the 2000s have been sought for comparison. Data has been gathered from literature, seminars and internet sources. The sources are mentioned with each case study. In this report, the climatic effects compared are: the greenhouse gas emissions of a building (kgco2e) at different stages of its life cycle The need of a building for primary energy at different stages of its life cycle (MJ or kwh) The use of natural resources at different stages of its life cycle (kg) The E-value of the building (kwh/m2a) When going through the material, it became evident that there is comprehensive data only on greenhouse gas emissions or carbon footprint. Data about other climatic effects was documented only occasionally. For this reason, this report focuses on greenhouse gas emissions and the need for primary energy. The environmental impacts selected for comparison are only some of the environmental indicators accordant with standard EN The starting point of this comparison was to study the effect of building materials on climate change and, because of this, the examination was limited to key indicators. It is noteworthy that comparative studies based on standards are still very few. A partial reason for this is that the latest EN standards have only been in use for a few years. Furthermore, they are not meant for scientific use but only as guidelines in the preparation of environmental specifications for buildings and technical environmental comparisons. Both perspectives are needed in order to reduce the environmental impact of construction.

6 Compared buildings No. Country Project Comparison Building type 1 UK Bridport 2013 Apartment block 2 UK Murray Grove 2011 Apartment block 3 Sweden Wälludden 2013 Apartment block 4 Finland Metla Research Centre 2006 Office building 5 Finland PuuEra 2012 Apartment block 6 Poland Energy-efficient houses 2013 Detached house 7 Italy Centro Sociale 2008 Public building 8 Italy Nidi Nel Verde 2009 Public building 9 Sweden Trähus Apartment block 10 Canada Comparison of type houses 2004 Detached house 11 USA Type house in Minneapolis 2004 Detached house 12 USA Type house in Atlanta 2004 Detached house 13 Germany Energy-efficient house 2004 Detached house 14 Sweden Apartment block 2004 Apartment block 15 Sweden Apartment block quarter 2004 Apartment block 16 Sweden Trä Apartment block 17 Austria Zero-energy house 2014 Detached house 18 Finland Tervakukka passive house 2012 Detached house

7 Limits and factors of uncertainty Scientific publications are usually peer-reviewed. Because of that, their results can be considered reliable, even if they do not observe standard calculation methods. In some of the reports, the results are given numerically. In some, the results are presented as column diagrams without numbers. In the latter cases, the figures are assessed graphically. This causes small inaccuracies, but the key order of the results does not change. It seems probable that, behind the different studies, there are no uniformly applied EN- or ISO-standard guidelines for the environmental comparison of buildings or building products. This is mostly because the environmental assessment standards of buildings (e.g. EN15643, EN15978, EN15804, EN16485, ISO14067) were not yet available during the preparation of the studies. Although the standards do guide the preparation of environmental specifications and the technical environmental assessment of buildings, they do not have a guiding or binding effect on scientific work. The purpose of most background reports has not been to prepare standard-compliant environmental calculations, but to examine buildings from a scientific perspective. This report is not an environmental statement aimed at marketing communication. The interpretation of this report should be done using original research results, which are given in the list of sources.

8 Part 2 SLIDES

9 How do different building materials affect carbon footprint? In Europe and the USA, many independent studies have been carried out about the carbon footprint of building materials and the need for primary energy. In the light of the 15 compared studies, it can be said that the climatic effects of a timber frame seem to be lower, irrespective of the calculation method or calculation framework. Picture: Matti Kuittinen

10 Method of presenting the results A summary of the content of the study. Photograph of the subject and source of image. Study results shown as percentages. Source reference and link The gradual outlining of the life cycle of subjects reported on in the study The life cycle stages involved are in bold.

11 Modules of the life cycle of a building based on standard EN15978 A1-3 A4-5 B C D PRODUCT STAGE CONSTRUCTION STAGE OF USE STAGE OF DEMOLITION FURTHER INFORMATION A1 Purchase of raw materials A2 Transport to manufacture A4 Transport to the building site A5 Site functions B1 Use of the product in the building B2 Maintenance B5 Large-scale repairs B6 Use of energy C1 Demolition C2 Transportation Benefits or inconveniences not included in the life cycle of the building A3 Product manufacture B3 Repair B7 Use of water C3 Processing of demolition waste B4 Change of parts C4 Final disposal of demolition waste

12 Apartment block Bridport London, UK 2013 The carbon footprint of the manufacture of the building materials for an apartment block was compared with regard to a CLT (cross-laminated timber) and a concrete frame. The emissions eliminated using the timber frame are equal to the entire energy consumption of the building over 12 years. Greenhouse gases Picture: buildingproducts.co.uk 22,70% CLT Concrete Source: J. Fovargue, ASBP London,

13 Apartment block Murray Grove London, UK 2009 The carbon sink and carbon footprint of the manufacture of the frame of a tall apartment block were compared. A massive wood CLT frame stores about 188 tonnes of carbon from the atmosphere A similar concrete frame would cause about 124 tonnes of fossil fuel emissions Carbon sink v. carbon emission (tonne C) Picture: buildingproducts.co.uk CLT Concrete Source: TRADA

14 PuuEra Vierumäki, 2012 The carbon footprint throughout the life cycle of a passive energy-level apartment block was compared with regard to timber and concrete frames. The calculations did not take into account the carbon sink of the timber frame. Greenhouse gases 94,00% Picture: Saint Gobain Concrete Source: Pasanen, P. et al. (2011). The carbon footprint throughout the life cycle of a passive-level apartment block A case study of the climatic effects of an apartment block Sitra reports 63 sarja/selvityksia63.pdf

15 Metla Research Centre, Joensuu, Finland 2005 The carbon footprint of the manufacture of a building frame and the need for primary energy were assessed. A timber frame and a concrete frame were compared. In the study, the resource efficiency and price of the alternative solutions were also examined. Greenhouse gases Energy 66,99% Picture: 40% Concrete Concrete Source: Häkkinen, T. and Wirtanen, L. (2006). Assessment of environmental and lifecycle perspectives by the Metla Joensuu Research Centre. VTT Bulletins

16 Wooden apartment block Wälludden Växjö, Ruotsi The carbon footprint of the manufacture of apartment block frames was compared with regard to timber and concrete structures. The study also dealt extensively with the key differences between the climatic effects of different wooden structures. Greenhouse gases 58,70% Picture: Svenskt Trä Concrete Source: Dodoo, A. et al. (2013). Wälludden as a case study for three new wood building systems. Published in Wood in Carbon Efficient Construction (Kuittinen et al., 2013).

17 Centro Sociale Rignagno Sull arno, Italy 2008 The carbon footprint of the manufacture of a building frame and the need for primary energy were assessed. A timber frame and a concrete frame were compared. Greenhouse gases Energy 58,0 % Picture: Strutture di Legno 42,0 % Concrete Concrete Source: Paolo Lavisci (2008), Centro Sociale Rignano Sull arno.

18 Nidi Nel Verde Rome, Italia 2009 The frame of the same building was designed from wood and concrete. The carbon footprint of the manufacturing stage of alternative materials was calculated. Greenhouse gases Picture: Strutture di Legno 38,0 % Concrete Source: Paolo Lavisci (2009), Nidi Nel Verse - Rome.

19 Energy-efficient detached house Poland, 2008 A passive energy-class detached house was compared using as a frame timber and a masonry structure. Under inspection were the manufacture of the materials, construction work, use and demolition. Greenhouse gases 42,1 % Masonry Source: Pajchrowski, G. et al. (2013). Wood as building material in the light of environmental assessment of full life cycle of four buildings.

20 Trähus 2001 Malmö, Sweden 2001 A wooden apartment block was built for the Malmö Housing Fair using a patented frame solution. The emissions from the frame manufacture, construction and demolition stages and the need for energy were compared with regard to timber and concrete frames. Greenhouse gases Energy Picture:. 7,5 % Trähus 2001 Concrete 42,5 % Trähus 2001 Concrete Source: Erikson, P-E (2004). Comparative LCA:s for Wood and Other Construction Methods.

21 Canadian type houses The Athena Institute designed a residential type house from timber, steel and concrete. After some precise quantity surveying, the carbon footprint of the manufacture of the materials and the need for primary energy were assessed. Greenhouse gases Energy Picture: Athena Sustainable Materials Institute 81,0 % 66,7 % Steel Concrete 69,0 % 45,2 % Steel Concrete Source: Trusty, W.B. and Meil, J.K. (2004). Building Life Cycle assessment. Residential Case Study. Athena Sustainable Materials Institute, Canada.

22 Type house Minneapolis, USA 2004 The type house frame was designed from both timber and steel. The carbon footprint of the manufacturing and the need for primary energy were compared. Greenhouse gases Energy 67,0 % 60,4 % Steel Steel Sources: Eriksson, P-E.Comparative LCA:s for Wood and Other Construction Methods. Lippke, B. et al. (2004). CORRIM: Life-Cycle Environmental Performance of Renewable Building Materials. Journal of Forest Products, vol 54, no. 6,

23 Type house Atlanta, USA 2004 The type house frame was designed from both timber and steel. The carbon footprint of the manufacturing and the need for primary energy were compared. Greenhouse gases Energy 71,6 % 58,8 % Steel Steel Sources: Eriksson, P-E.Comparative LCA:s for Wood and Other Construction Methods. Lippke, B. et al. (2004). CORRIM: Life-Cycle Environmental Performance of Renewable Building Materials. Journal of Forest Products, vol 54, no. 6,

24 Detached house Germany, 2002 The German house frame was designed from both timber and brick. The carbon footprint of the entire life cycle of the frame materials and the need for primary energy were compared. The emissions from the stage of use were assumed to be the same. Greenhouse gases Energy 83,5 % 72,5 % Brick Brick Sources: Eriksson, P-E (2004). Comparative LCA:s for Wood and Other Construction Methods. Scharai-Rad, M. and Welling, J (2002). Environmental and energy balances of wood products and substitutes.

25 Apartment block Lund, Sweden The building's frame was designed from both timber and concrete. The need for primary energy throughout the building's life cycle was compared. The need for energy during the stage of use was assumed to be the same between comparable structures. Energy 63,6 % Concrete Sources: Eriksson, P-E (2004). Comparative LCAs for Wood and Other Construction Methods. Adalberth, K. (2000). Energy Use and Environmental Impact of New Residential Buildings. Journal of Building Physics.

26 Apartment block quarter Sweden The carbon footprint of the frame structures of a large apartment block quarter and the need for primary energy were compared. An examination was carried out for the entire life cycle, assuming that there are no significant differences in the stage of use. Greenhouse gases Energy 58,7 % 36,4 % Concrete Concrete Sources: Eriksson, P-E (2004). Comparative LCAs for Wood and Other Construction Methods. Berge, B. and Stoknes, S. (2004). Reduksjon av klimabelastninger fra byggebransjen - ved økt bruk av tre og annen biomasse. Aktiv substitusjonseffekt ved økt treforbruk i nybygg.

27 Trä 8 Gothenberg, Sweden 2013 The carbon footprint of the manufacture of frame alternatives for a six-storey apartment block and the need for primary energy were assessed. The main components of a laminated veneer lumber frame and a concrete frame were compared. The study observed not only differences between the frame materials but also the great effect of the lift shaft and foundations on carbon footprint. Picture: Norwegian Institute of Wood Technology Greenhouse gases 72,9 % LVL frame Steel + Concrete Source: Tellnes, L.G.F. (2013). Assessment of carbon footprint of laminated veneer lumber elements in a six-storey house comparison to a steel and concrete solution.

28 Zero-energy house Austria An extensive comparative study found that the building materials and building technology of low-, passive- and zeroenergy houses and local energy sources affected the environmental impacts throughout the life cycle. Below are the climatic effects of a zero-energy house heated with a heat pump. Greenhouse gases Energy 95,01% 94,13% 100,00% 37,69% 0,03% Brick Concrete Brick Concrete Data collected from the source: Innovative Gebäudekonzepte im öko-logischen und ökonomischen Vergleich über den Lebenszyklus. Anhang 2: Ergebnisblätter der LCA und LCC Bilanzierung. C. Spitzbart, G. Fischer, 2014.

29 Tervakukka passive house Tampere, 2012 The object of comparison was the same building constructed with a timber frame and Siporex blocks. The U-value of the alternative structures was the same. The comparable values were the carbon footprint of the manufacture of the building materials. Greenhouse gases 65,9 % Picture: GreenBuild Oy Siporex-block Source: Kuittinen, M. (2013). Case studies - Tervakukka Passive House. Julkaisussa Wood in Carbon Efficient Construction (Kuittinen et al., 2013).

30 Summary Carbon footprint calculations comparing 19 buildings Source: Kuittinen, M. (2014). A comparison of the climatic effects of buildings A review of studies carried out in the 2000s. Rakennustuoteteollisuus ry Wood Products Division The average difference between the carbon footprints of building materials and the range of variation 120% 80% 94% 60% 40% 55% 20% 0% TIMBER FRAME 8% OTHER FRAME MATERIAL

31 Part 3 RECOMMENDATIONS FOR FURTHER ACTION

32 Reporting of the climatic effects of buildings As a result of this report, it has been possible to notice that the reporting of the climatic effects of buildings is done in a very chequered way. Therefore the climatic effects of the different stages of the life cycle of buildings should be presented in accordance with valid European standards: The bases of the environmental assessment of buildings: EN Calculation methods for the environmental assessment of a building: EN15978 The preparation of environmental specifications for building products: EN15804 The preparation of environmental specifications for wood-based building products: EN16485 At the very least, the carbon footprint of the manufacture of building materials and the E-value of the building should be linked to the climatic effects. Based on the relationship between carbon footprint and the E-figure, the carbon efficiency of a building can be calculated. Based on carbon efficiency and building costs, the carbon economy of a building can then be calculated. With the aid of these two descriptors, the climatic effects of a building can be optimised in relation to its energy class and construction costs. Both carbon efficiency and carbon economy have been studied more closely in a research report written by Aalto University for the City of Espoo Premises Centre (to be published at the end of 2014). In order to ensure the broadest possible and greatest comparability of data, it would also be advisable to take into account the Life cycle indicators of buildings guidelines prepared by the Finnish Green Building Council, which is based on standard EN15978.