An important contribution to an environmentally sustainable construction sector is the definition of benchmarks for environmental impacts. There are several databases available, but the question arises as to how consistent those are and whether they can be used to compare environmental performance of construction materials and/or components. In recent developments, the increasing number of environmental product declarations (EPDs) as a foundation for such reference values has come into focus. However, the robustness and comparability of EPDs remain uncertain.
This study examines how reference values can serve as benchmarking tools in construction, combining insights from a systematic literature review on reference value approaches in construction with a targeted assessment of EPD-based methods. The aim was to evaluate the suitability of EPDs for developing environmental sustainability benchmarks in construction. A two-layered analysis is conducted. First, a systematic literature review is performed to assess overarching benchmarking concepts. Second, a detailed analysis of EPD-based benchmarking was carried out, including a statistical analysis of existing EPDs, methodological comparison between EPDs and Product Environmental Footprint (PEF) reference products, and a critical review of existing EPD-based benchmarking frameworks.
The review confirms the importance of reference values for establishing comparability in LCAs and highlights the diversity of approaches. The statistical EPD analysis shows high GWP variability within identical PCRs and program operators, raising consistency concerns. Cross-comparison with PEF emphasised differences in benchmark definition, while existing EPD-based frameworks remain limited by inconsistent PCRs, data quality, and methodological flexibility. The high variability of EPD data suggests that benchmarks may need to be more regionally specified than on a national level. While EPDs provide a valuable data foundation in construction, a careful balance must be struck between precise rules to ensure comparability and sufficient flexibility to guarantee applicability across diverse products and contexts.