Economic Allocation in LCA: A Case Study About Aluminium Window Frames
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A traditional problem in LCA is how to deal with processes where recycled material is used as an input or where the output of a process is further used as raw material in another product system (open-loop recycling). Allocation is needed to partition the responsibility for the environmental impacts caused by the raw material extraction, the recycling and the final disposal of a material over different product systems in some proportional shares. The norm ISO/DIS 14’04T. 1998 now explicitly allows the use of an economic value as a basis for the allocation of open-loop product systems, where material is recycled into other product systems while undergoing a change in its inherent properties.
In a case study for aluminium window frames, an economic allocation procedure for aluminium is developed based on different market prices for secondary materials with different alloy content. Market prices are assumed to reflect the functionality of a material quality within a techno-economic system. Therefore, market prices permit the qualitative description of the degradation of a material over a product system. Based on this qualitative degradation, a ‘relative resource consumption’ can be defined. This relative resource consumption is used to allocate the environmental impacts related to recycled material entering or leaving the product system under study.
The results of the new allocation principle are compared to results of a former study on window frames out of various materials, elaborated by EMPA in 1996. The conclusions underline the importance of the recycling of aluminium with a high quality and give some criteria for a more ecological design of aluminium windows. Finally, methodological advantages and obstacles of the presented economic allocation procedure are pointed out.
KeywordsAllocation aluminium case studies economic allocation functionality LCA material quality open-loop recycling window frames
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- CML, 1992Heijungs, R.;Guinée, J.B. et al. (1992): Environmental Life Cycle Assessment of Products. Background and Guide. LeidenGoogle Scholar
- Frischknecht, 1998Frischknecht, R. (1998): Life Cycle Inventory Analysis for Decision-Making, Scopedependent Inventory System Models and Context-specific Joint Product Allocation. Diss ETH Nr. 12599, ETH Zürich, ZürichGoogle Scholar
- Huppes, 1992Huppes, G. (1992): Allocating Impacts of Multiple Economic Processes in LCA. In: Various 1992Google Scholar
- Nordic, 1995Lindfors, L.G. et al. (1995): LCA-Nordic Guidelines on Life-Cycle Assessment. Nordic Council 1995, Nord 1995:20, CopenhagenGoogle Scholar
- Richter, 1996aRichter, K.;Konniger, T.;Brunner, K. (1996): ökologische Bewertung von Fensterkonstruktionen verschiedener Rahmenmaterialien (ohne Verglasung). EMPA-SZFF-Forschungsbericht, DietikonGoogle Scholar
- Richter, 1996bRichter, K.;Brunner, K. et al. (1996): ökologische Bewertung von Wärmeschutzglas, Integraler Vergleich verschiedener Verglasungsvarianten. EMPA Dübendorf, DübendorfGoogle Scholar
- Various, 1992 Various (1992): Life-Cycle Assessment. Workshop Report on Life Cycle Assessment, Inventory, Classification, Valuation, Data Bases. SETAC-Europe, BrusselsGoogle Scholar