2023 Volume 19 Issue 2 Pages 64-71
In LCA studies, various approaches and methods have been proposed for evaluating environmental burdens and credits associated with the input and output of secondary resources across the product system boundary. Therefore, the evaluating the burdens related to secondary resources is still challenging because there is no common method. In fact, different materials have different recyclability, and different product designs have different recoverability for the materials contained in end-of-life products. Different methods may conclude different selections for a less footprint material and for a less-footprint product design through its life cycle. Therefore, this article introduces the concept of adding or avoiding environmental burdens induced by the consumption and recovery of secondary resources during the product life cycle in accordance with a consequential approach and outlines the calculation formulas based on this concept. And then, this article compares the formulas with the formulas compiled as circular footprint formula （CFF） in product environmental footprint category rules guidance published by the European Commission. It was found that some avoided impacts at the disposal stage are not properly assessed in CFF. It is because CFF accumulates elements of burdens practically. The difference between the theoretical formula and the formula based on practical accumulation is also theoretically described.
