Concept
System boundary
Also: life cycle stages · modules A1-A3 · cradle-to-gate · cradle-to-grave
The set of processes included in a life cycle assessment or carbon footprint, defined by which life-cycle stages, activities and flows are inside the study and which are excluded.
The system boundary determines what an environmental result actually covers. Two studies of the same product with different boundaries will produce different numbers, and both can be correct.
Common boundaries
Cradle-to-gate covers raw material extraction, transport and manufacturing up to the point where the product leaves the factory. Cradle-to-grave adds distribution, installation, use, maintenance and end of life. Gate-to-gate covers a single process step. Cradle-to-cradle extends to reuse and recycling benefits.
Modules in EN 15804
Construction EPDs express the boundary as modules: A1 to A3 (product stage), A4 and A5 (construction process), B1 to B7 (use stage), C1 to C4 (end of life) and D (benefits and loads beyond the system boundary). The PCR sets which modules are mandatory.
Cut-off criteria
Standards allow small flows to be excluded under stated cut-off rules, typically expressed as a share of mass, energy or environmental significance. Cut-off decisions must be documented because they affect completeness.
Where Verdatir fits
Verdatir checks that the declared boundary matches the PCR, that mandatory modules are present, that exclusions are justified, and that a boundary assumption stated at the start is applied consistently through the whole study.
Sources and further reading
In practice
Verdatir turns the rules behind this term into automated checks with a reviewer in the loop.
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