WOOD-BASED BUILDING PRODUCTS ENVIRONMENTAL ASSESSMENT ACCORDING TO THE ENVIRONMENTAL PRODUCT DECLARATION STANDARD

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1 WOOD-BASED BUILDING PRODUCTS ENVIRONMENTAL ASSESSMENT ACCORDING TO THE ENVIRONMENTAL PRODUCT DECLARATION STANDARD Lauri Linkosalmi 1, Matti Kairi 2 ABSTRACT: Environmental impacts of buildings and building products have raised an important issue besides the energy efficiency. Greenhouse gas emissions are the most studied environmental impact in the building product point of view. Several novel standards guide the environmental assessment work and give methodological boundaries for the assessment. However, different assessments are not compatible; there is a disagreement from the assessment methods, as allocation procedure in a multi-output processes and carbon neutrality of the renewable energy. Woodworking industry and interest groups should define common assessment methodology for wood-based materials, which would provide harmonized datasets for the buildings environmental assessment. KEYWORDS: Environmental product declaration, Greenhouse gas emissions, Wood-based products 1 INTRODUCTION 123 It is estimated that the built environment causes approximately 40 per cent of the all greenhouse gas emissions annually. Energy efficient aspect of buildings has been discussed broad and also new regulations and legislations have regulated to improve energy efficiency of buildings. At the same time greenhouse gas emission of the built environment are aiming to reduce by European Union. Results of the recent WoodWisdom-Net project, CO2 Wood in Carbon Efficient Constructions, shows that when the construction sector is moving on to nearly zero-energy buildings, in near future, importance of building materials environmental performance will increase over the building life cycle [1]. This study focuses on the life cycle assessment methodology to unify assessment rules for the wood-based building products. In the assessment different methods can have a significant effect to the results. environmental product declaration (EPD) standard (EN 15804) [2] and to define more specific rules for different material groups there are product category rules standards under development. For the wood-based products there is standard accepted. EN [3] standard specifies some assessment methods for wood products as how the biogenic carbon, the carbon neutrality and the allocation procedure should be handled. Wood material biogenic carbon content calculations rules are dealt in EN standard [4]. Assessment is following life cycle assessment principle, which is shown in Figure 1. Inputs and outputs are monitoring and emissions to air, soil and water are specified. 2 METHODS European Standards series the Sustainability of construction works guide assessment methods for the building and building product level sustainable assessment. Technical Committee 350 has prepared this standard series. For the product level assessment has developed 1 Lauri Linkosalmi, Aalto University, Tekniikantie 3, Espoo, Finland. lauri.linkosalmi@aalto.fi 2 Matti Kairi, Aalto University, Finland Figure 1: Main principle of the life cycle assessment.

2 2.1 LIFE CYCLE PHASES In the sustainability of construction work standard series the life cycle phases are divided in four categories; production stage (A1 3), construction stage (A4 5), use stage (B1 7) and end-of-life stage (C1 4). Also some additional information can be stated in the module D, information module. For the product level assessment at least stages A1, A2 and A3 need to be assessed, in addition some other modules can be added. Life cycle stages are shown in Figure 2. Figure 3: Content of the production stages. 2.2 ALLOCATION In this study sawmill process is studied to compare allocation methods impact to the final assessment results of sawmilling products [5]. EN standard refers to avoid the allocation procedure in the assessment, but in a multi-output process, as woodworking, is it sometimes only option to deal the issue. Standard specify: Physical allocation shall be used when the difference in revenue is low; Otherwise economic allocation shall be used; Case of material flows is carrying specific inherent properties allocation shall always done according physical flows. [2] In this study used assessment methods were physical allocation (volume or mass), economic allocation (value based) and as a third option main product allocation. Which mean, that all environmental impacts of the manufacturing stage were allocated to the main product. Studied process was sawmilling and its products. Main rule for the allocation is shown in Figure 4. Figure 2: Life cycle stages according EN [2]. Product stage assessment includes phases form the raw material acquisition untill finished product at mill. A1 stage includes all raw materials acquisition, for wood working industry main material are logs from the forest. Stage includes all forest operation including cultivation and forest management. Transportation stage (A2) considers all transportation activities to the mill. A3 stage, manufacturing, include all operations in the mill. Content of stages are presented in Figure 3. Figure 4: Allocation options for product stages.

3 For the assessment following allocation factors were used: Allocation factor 1 Allocation was based on physical values of products (volume). All products from sawmill were observed; sawn timber, chips, sawn dust, cutter shavings and bark. Normally the yield of sawmill is between , the rest are different by-products. Equation (1) determines allocation factor 1. [volume(i)] allocation factor[%] = (1) [volume(1)+ + volume(n)] volume(i) = volume of studied product volume(1) = volume of product 1 volume(n) = volume of product n (1,2,3 n) Allocation factor 2 Allocation is based on economic value and quantities of sawmill products. In this study the price of sawmill products was estimated with certain reference values; sawn timber 1, chips 0.15, sawn dust 0.1 and cutter shavings & bark 0.05 [6]. Equation (2) determines allocation factor 2. [volume(i) x price(i)] allocation factor[%]= (2) [volume(1) x price(1)+ + volume(n) x price(n)] volume(i) = volume of studied product price(i) = price of studied product volume(1) = volume of product 1 price(1) = price of product 1 volume(n) = volume of product n (1,2,3 n) price(n) = price of product n Allocation factor 3 In this factor all burdens from A3 stage were allocated to the main product, sawn timber. No burdens for by-product were stated. 2.3 ASSESSMENT DATA Life cycle inventory was run from three European sawmill. Inventory data was collected by personnel of sawmills in the common inventory template. Supplementary information was asked in need. Life cycle assessment was carried out with GaBi 4 software. Data for assessment was selected mainly from the 2.0 database, and to complete data some datasets were picked from the GaBi database. All used datasets are listed in Table 1. Table 1: Used datasets. Material/Process Pine log Spruce log Dataset NORDE: sawn timber, Scandinavian softwood, raw, plant-debarked, u=70%, at plant, RER: round wood, softwood, under bark, u=70% at forest road, / NORDE: round wood, Scandinavian softwood, under bark, u=70% at forest road, Diesel RER: diesel, at regional storage, Petrol RER: diesel, at regional storage, Plastic RER: packaging film, LDPE, at plant, Paper RER: kraft paper, bleached, at plant, Steel RER: chromium steel product manufacturing, average metal working, Wooden splinters RER: sawn timber, softwood, raw, kiln dried, u=20%, at plant, / NORDE: sawn timber, Scandinavian softwood, raw, plant-debarked, u=70%, at plant, Paint RER: alkyd paint, white, 60% in H2O, at plant, Solvent RER: white spirit, at plant, Impregnation chemicals Rubber Oil products Oil products, vegetable based Social water Process water Heat Electricity Truck transport Train transport, diesel Train transport, electricity Waste to landfill RER: wood preservative, organic salt, Cr-free, at plant, RER: synthetic rubber, at plant, RER: lubricating oil, at plant, RER: glycerine, from rape oil, at esterification plant, RER: Drinking water, ELCD/PE-GaBi RER: Process water, ELCD/PE- GaBi EU-27: Waste incineration of untreated wood, ELCD/CEWEP /PE-GaBi Powermix (country specific), RER: transport, lorry >32t, EURO4, RER: operation, freight train, diesel, RER: operation, freight train, electricity, RER: Landfill (Commercial waste for municipal disposal; AT, DE, IT, LU, NL, SE, CH), PE-GaBi/ RER: Landfill (Commercial waste for municipal disposal; FR, UK, FI, NO), PE-GaBi

4 2.4 ASSESSMENT INDICATOR In this study global warming potential (GWP) was calculated to indicate greenhouse gas emissions (GHG) of sawmill products. Indicator shows result in kg CO 2 equivalent, where all greenhouse gases are transformed to CO 2 values with different multipliers according to their harmfulness for the global warming. Table 2 is showing global warming potential of most common greenhouse gases. case the total impact from stages A1 3 is 61 per cent for the sawn timber. Figure 6 shows share of all products. Table 2: GWP of most common greenhouse gases for global warming potential indicator [7]. Greenhouse gas Chemical formula Multiplier Carbon dioxide CO 2 1 Methane CH 4 25 Nitrous oxide N 2 O RESULTS This study shows that selected allocation method can have a significant effect to the share of greenhouse gas emissions of the sawmilling products. Totally share of sawn timber impacts was between 46 and 66 percent. 3.1 IMPACT OF ALLOCATION Allocation factor 1, physical allocation, gives lowest impact for the sawn timber. Sawn timber share is 46 per cent; by-products cover 54 per cent of impacts. According to the studied of sawmills are impacts between per cent from production volumes. Distribution of the impacts is presented in Figure 5. Figure 6: The impact distribution from stage A1 3 using allocation factor 2. Allocation factor 3 (Figure 7) gives almost equal impact results as allocation factor 2. This similarity is coming from the high price of sawn timber and on the other hand rather low price from other sawmill products as chips, sawn dust and bark. Total 66 per cent of impacts are placed to the sawn timber. Figure 5: The impact distribution from stage A1 3 using allocation factor 1. When allocation of the sawmilling process (A3) is done using economic allocation, is impact for the main product per cent from the manufacturing process. In that Figure 7: The impact distribution from stage A1 3 using allocation factor 3. As shown, allocation method can have major impact to the result. Allocation method choice has a vital impact to the final results of assessment and given values.

5 3.2 GLOBAL WARMING POTENTIAL Global warming potential was assessed to show allocation methods impact to the environmental indicator. Fossil and total global warming potential were studied, where total global warming potential includes fossil and biogenic greenhouse gas emissions. Results of impact assessment are shown in figure 8. Figure 8: Global Warming Potential of the sawn timber with different allocation methods. Factor 3 gives biggest impact in both GWP cases fossil & total. In fossil GWP results difference between factor 1 and 3 is almost 1.5 times and in total GWP values is difference double. Allocation method can have a significant impact to the impact assessment results. 4 CONCLUSIONS Despite of all the standardization work, different assessment methods can and are still used for the environmental assessment of building products. That leads to the situation were different datasets are not comparable with each other and confuse users of the environmental datasets as an environmental product declaration. ACKNOWLEDGEMENT The WoodWisdom-Net project CO2 Wood in Carbon Efficient Constructions lasted years This work has been supported by the Finnish Cultural Foundation, Stora Enso Building and Living, and Tekes the Finnish Funding Agency for Technology and Innovation. REFERENCES [1] Kuittinen M. et. al.: Wood in carbon efficient construction - Tools, methods and application. CEI Bois, [2] EN Environmental product declarations - Core rules for the product category of construction products. European Committee for Standardization, Technical Committee 350, Sustainability of construction works, [3] EN Environmental Product Declarations - Product category rules for wood and wood-based products for use in construction. European Committee for Standardization, Technical Committee 175, Round and sawn timber, [4] EN Wood and wood-based products - Calculation of the biogenic carbon content of wood and conversion to carbon dioxide. European Committee for Standardization, Technical Committee 175, Round and sawn timber, [5] Jungmeier G. et. al.: Allocation in LCA of Woodbased Products - Experiences of Cost Action E9. The International Journal of Life Cycle Assessment, Springer, 7(5): , [6] EUWID: Wood products and panel, Market reports: Sawn softwood Germany and Sawmill residues Germany. Available cited [7] Intergovernmental Panel on Climate Change (IPCC): IPCC Fourth Assessment Report: Climate Change The Physical Science Basis. Available s_and_data_reports.shtml 2007, cited As shown in this study, choice of the assessment method can have a significant effect to the greenhouse gas emissions of the sawn timber. It is recommended in EPD standard [2] to avoid allocation, which would be possible by using subdivision method of production step, but in practice it is possible only on few cases at the moment. For the subdivision method would be needed more divided measurement data from the mills in different production phases. One practical solution would be that wood product industry and interest groups agree on a common assessment method to unify assessments. This would harmonize environmental impacts assessments in woodworking industry field and provide more comparative wood-based building products datasets.