Functional Unit definition in a circular economy perspective: implication for LCA normalisation for a footwear outsole

Abstract

It is a significant challenge to address the complex issue of comparing multiple products with the same function but distinct characteristics in the circular economy framework and its implications for Life Cycle Assessment (LCA) in the footwear sector. Our strategy involved developing a specific methodology for determining the durability characteristic of physical products, which was accomplished by combining the results of various physical tests. In particular, a set of urban soles was examined for the case study. The environmental footprints of the footwear were then normalised using this durability metric, aligning them with the number of units required to reach practical quality levels. Using this method, we achieved substantial changes in the results of the LCA analysis, particularly in the context of products whose design prioritised particular qualities like durability. As a result, this research emphasises the necessity of redefining the functional unit, particularly from the circular economy perspective, and illustrates how it may positively impact company eco-design policies.