A practice‐based framework for defining functional units in comparative life cycle assessments of materials

In comparative life cycle assessment (LCA) studies of materials, there is a mismatch between the current practice and existing guidelines regarding functional unit definition. The purpose this study to develop practice-based framework for defining units in LCAs materials provide guidance which situations different types are relevant. A literature review identified three units: (i) reference flow unit, (ii) property (iii) performance unit. These types, only latter strictly complies with LCA guidelines, represent varying degrees equivalence technological maturity. most relevant type depends on goal study. We suggest that screening assessments whether have comparable environmental impacts can apply units. Material comparisons certain application areas some important properties For end products, be applied. However, even such cases, complete hardly achieved due more or less product differences. applicability demonstrated case comparing cemented carbide polycrystalline diamond hard materials.