LCA Methodology Foundations: Goal, Scope, Functional Unit, Boundary and Allocation
What the exam tests
This domain checks whether you can structure a study the way ISO 14040:2006 and ISO 14044:2006 (with its amendments) require: four iterative phases - goal and scope, inventory, impact assessment, interpretation - where findings in a later phase force revisions of earlier decisions.
Core rules
- Goal fixes the intended application, reasons, audience, and whether results are disclosed publicly. A comparative assertion disclosed to the public triggers mandatory review by interested parties.
- Functional unit is the quantified performance of the system that serves as the reference; the reference flow is the amount of product needed to deliver it. FU statements carry quantity, quality and duration, e.g. "1 L of chilled beverage delivered to the point of sale".
- System boundary must match the FU: life-cycle stages covered, treatment of capital goods, and cut-off criteria (mass, energy, environmental relevance).
- Allocation hierarchy (ISO 14044 §4.3.4): first avoid allocation by subdivision or system expansion; then allocate using an underlying physical relationship; economic allocation is the last resort.
Worked example
Compare 1 L of beverage in PET versus returnable glass. Choosing "1 kg of packaging" as the FU would flatter glass. Choosing "1 L delivered" forces you to model the ~1.05 kg of packaging plus return-trip logistics per litre. The multi-output recycling step is resolved by system expansion, crediting the avoided virgin PET; you must document the substituted product and the dataset used for it.
Traps
Confusing FU with reference flow; picking an FU that pre-judges the comparison; mismatched boundaries (cradle-to-gate for one system, cradle-to-grave for the other); undocumented allocation; forgetting that comparative public claims need a review panel, not just a peer read.