Chalmers Conferences, LCM 2013

Francois Cluzel, Yann Leroy, Bernard Yannou

Last modified: 2014-09-11


Functional Unit (FU) ensures the consideration of comparable product quantities to provide reliable Life Cycle Assessment (LCA) results. Although the definition of this FU is essential, it receives only a few attention in the normative texts. A high part of subjectivity is let to the LCA practitioner. In this paper variability sources of the FU definition are identified to propose a more structured and adapted approach. Literature references and data collected among 8 LCA experts on 5 case studies allow us to draw first recommendations towards a more structured FU definition framework.


Life Cycle Assessment (LCA); Goal and Scope definition; Functional Unit; Variability


Collado-Ruiz, D., & Ostad-Ahmad-Ghorabi, H. (2010a). Fuon theory: Standardizing functional units for product design. Resources, Conservation and Recycling, 54(10), 683‑691. doi:10.1016/j.resconrec.2009.11.009

Collado-Ruiz, D., & Ostad-Ahmad-Ghorabi, H. (2010b). Comparing LCA results out of competing products: developing reference ranges from a product family approach. Journal of Cleaner Production, 18(4), 355‑364. doi:10.1016/j.jclepro.2009.11.003

Cooper, J. (2003). Specifying functional units and reference flows for comparable alternatives. The International Journal of Life Cycle Assessment, 8(6), 337‑349. doi:10.1007/BF02978507

Esterman, M., Fumagalli, M. E., Thorn, B., & Babbitt, C. (2012). Towards parametric environmental profiles of complex industrial systems in preliminary design stage. In Proceedings of the ASME 2012 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2012. Chicago, Illinois, USA.

International Organization for Standardization. (2006a). ISO 14040:2006 - Environmental management - Life cycle assessment - Principles and framework (ISO Standard).

International Organization for Standardization. (2006b). ISO 14044:2006 - Environmental management - Life cycle assessment - Requirements and guidelines (ISO Standard).

Joint Research Center - Institute for Environment and Sustainability. (2010). ILCD Handbook - General guide for Life Cycle Assessment - Detailed guidance v1.0 (No. EUR 24708 EN). European Commission.

Reap, J., Roman, F., Duncan, S., & Bras, B. (2008). A survey of unresolved problems in life cycle assessment - Part 1: goal and scope and inventory analysis. The International Journal of Life Cycle Assessment, 13(4), 290‑300. doi:10.1007/s11367-008-0008-x

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