LCA Boundary Definition Checklist v2.1

LCA boundary definition is the foundational step that determines which processes, inputs, outputs, and life cycle stages are included or excluded from an assessment—directly influencing result validity, comparability, and decision relevance. The checklist guides practitioners through hierarchical decisions: first clarifying the study’s goal and scope (e.g., cradle-to-gate vs. cradle-to-grave), then specifying the functional unit and reference flow, followed by mapping unit processes using process diagrams or input–output matrices. It explicitly addresses spatial (geographic), temporal (time horizon for emissions, e.g., 100-yr GWP), and technological boundaries (e.g., whether upstream recycling infrastructure or end-of-life treatment is modeled). A key strength of v2.1 is its structured treatment of allocation—requiring justification for system expansion versus partitioning—and integration of dynamic cut-off rules (e.g., 'exclude processes contributing <1% to cumulative energy demand or global warming potential') validated against sensitivity analysis. Furthermore, it embeds data quality requirements (DQR) per ILCD Handbook, mandates documentation of boundary assumptions in the LCA report’s appendix, and includes prompts for stakeholder review to mitigate subjectivity and enhance credibility in regulatory or certification contexts.