Selection of Impact Categories and Classification of LCI Results to Impact Categories

This chapter concerns ‘selection of impact categories’ and ‘assignment of LCI results to selected impact categories (classification)’. These elements are the first two mandatory elements of Life Cycle Impact Assessment (LCIA). They have largely been developed during the 1990s. In practice these mandatory steps are often performed using default lists of impact categories and default lists of inventory items classified to these default impact categories as part of LCA handbooks, guides and software tools. Despite these default lists, it is still important to pay sufficient attention to both these steps in any LCA case study. Every practitioner of LCA will always need to justify the completeness of default lists of impact categories and default classification lists for their study. In addition, the handling of missing information needs to be reported explicitly and transparently, and needs to be taken into consideration when developing conclusions and recommendations for the study at stake. After the 1990s, the attention to selection of impact categories and classification in LCA methodology studies and papers has been limited. Still, there are issues that deserve further attention from LCA method developers such as the harmonisation of naming impact categories while distinguishing or not between names for midpoint impact categories and names for endpoint category indicators, keeping default lists of impact categories manageable, and the classification of inventory results that relate to more than one impact category.