P r o g r e s s
New thinking on wood. Purchasing and manufacturing products that incorporate wooden components can greatly reduce the overall embedded carbon footprint of those goods and the buildings into which they are employed.
Wood – another low carbon footprint solution With the International Panel on Climate Change (IPCC) warning that at least 60 per cent reductions in greenhouse gas emissions will be needed to stabilise emissions at double pre-industrial levels, organisations across a range of industry sectors are now considering where such deep cuts can be achieved at a profit. There are some surprisingly simple and practical options already being successfully employed. How many consumers in Australia, for example, realise that using more sustainable plantation timber products significantly reduces your carbon footprint? Life Cycle Analysis (LCA) studies show that plantation timber products have a far less harmful ‘footprint’ than many other materials in terms of greenhouse gas emissions and embodied energy. If sourced from sustainably managed plantations, timber products can significantly reduce the greenhouse gas emissions impact from activities such as building, and products such as furniture, entertainment units, flooring materials, window frames and playground and park seats, to name a few. In fact, LCA studies show that of all the materials considered, plantation timber has
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the lowest environmental impact compared to other options. Why is that? Let’s consider how plantation timber performs in terms of greenhouse gas emissions when compared to other materials in a few key consumer markets. Within the building sector, a comparison of three houses established by researchers1 calculated that a predominantly steel house contains 553 GJ of embodied energy, whilst a predominantly concrete house contains 396 GJ. A predominantly timber house contains just 232 GJ. Similarly, recent research2 made a comparative assessment of steel, concrete and wood building material and found that wood had the lowest embodied energy. Also, the higher the embodied energy of the building, the more air toxins
(such as carbon dioxide, sulphur dioxide, particulates, nitrogen oxides and hydrocarbons) were released into the atmosphere. Steel and concrete buildings are therefore much worse in this respect. Flooring is a significant market globally, and LCA studies of three different types of material for flooring (solid wood, linoleum and vinyl/PVC) have been assessed.3 The functional unit was defined as 1 m2 of flooring and the considered lifetimes of each of the products were based on real world data of average lifetimes: 25 years for linoleum, 20 years for PVC and 40 years for wood. The wood flooring was found to consume the lowest amount of energy in manufacturing (electricity and fossil fuel), followed by linoleum and PVC. By comparing global warming potentials of these flooring materials, this study showed that PVC had the highest global warming potential (GWP) of 4.2 kg/m2. This was 2.5 times greater than linoleum (1.6 kg/m2), while the GWP of wood was negligible (0.42 kg/m2). In other measures – such as acidification potential and photochemical ozone creation potential – wood was found again to be the best performer. LCA studies of window frames again showed the same trend for wood, compared with aluminium and PVC, in terms of global warming potential, acidification potential, eutrophication potential and photochemical ozone creation potential.4 But does this footprint benefit extend to the use of wood components in particular products? Absolutely. LCA studies looking at the effect of including more wood in entertainment units for TVs and DVD players, for example, found that wood reduces the overall environmental load of the product.5 LCA studies of office furniture suggest there is great potential for timber furniture, or at least office furniture with higher timber content, to make a significant difference to greenhouse gas emissions. Furniture (particularly in the office environment) can contribute a surprising amount to the overall environmental impact of a building. A number of analyses of office and residential buildings show
1 Buchanan AH and Honey BG (1994) Energy and carbon dioxide implications of building construction. Energy and Building 20, 205–217. 2 Glover J (2001) Which is better? Steel, concrete or wood. A comparison of assessments on three building materials in the housing sector. Fourth year thesis, Department of Chemical Engineering, University of Sydney. (In this work, the comparison of embodied energy was derived from data obtained by Lawson B (1996) Building Materials Energy and the Environment. Towards Ecologically Sustainable Development. The Royal Australian Institute of Architects, and The Canadian Wood Council (1994–2000) Life cycle analysis for residential buildings. Canadian Wood Council Technical Bulletin No. 5.) 3 Jönsson A, Tillman A and Svensson T (1997) Life cycle assessment of flooring materials – case study. Building and Environment 32(3), 245. 4 Findings of Glover J, (2001) and Jönsson A, et al (1997) summarized in this article are based on the research presented in Taylor J, Langenberg, K V, (2003) Review of the Environmental Impact of Wood Compared with Alternative Products Used in the Production of Furniture. Forest and Wood Products Research and Development Corporation (FWPRDC). 5 Nedermark R (1998) Ecodesign at Bang & Olufsen. Product Innovation and Eco-efficiency. Twenty-three Industry Efforts to reach the Factor 4. (Eds J Klostermann and A Tukker). Kluwer Academic Publishers.
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