Comparing product category rules from different programs: learned outcomes towards global alignment

PURPOSE: Product category rules (PCRs) provide category-specific guidance for estimating and reporting product life cycle environmental impacts, typically in the form of environmental product declarations and product carbon footprints. Lack of global harmonization between PCRs or sector guidance documents has led to the development of duplicate PCRs for the same products. Differences in the general requirements (e.g., product category definition, reporting format) and LCA methodology (e.g., system boundaries, inventory analysis, allocation rules, etc.) diminish the comparability of product claims. METHODS: A comparison template was developed to compare PCRs from different global program operators. The goal was to identify the differences between duplicate PCRs from a broad selection of product categories and propose a path toward alignment. We looked at five different product categories: milk/dairy (two PCRs), horticultural products (three PCRs), wood–particleboard (two PCRs), and laundry detergents (four PCRs). RESULTS AND DISCUSSION: Disparity between PCRs ranged from broad differences in scope, system boundaries, and impacts addressed (e.g., multi-impact vs. carbon footprint only) to specific differences of technical elements. The differences primarily reflected the different purposes of the PCR (e.g., label/report), the different standards they were based on (e.g., ISO 14025/PAS 2050), the use of different product categorization systems, or simply the result of being developed independently. Differing degrees of specificity and terminology between PCRs allowed for varied interpretation—at times making direct comparison difficult. For many of the differences between PCRs, however, there was no clear rationale why they could not be consistent in the future. CONCLUSIONS: These results were used to outline a general guidance document for global alignment of PCRs which recommends (1) alignment of PCRs for different purposes, (2) provision of guidance for the adoption of aspects of other PCRs, and (3) provision of greater specificity on content. The overall recommendations also suggest collaboration among program operators to facilitate alignment on issues that evolve from independent development.