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Product carbon

The boundary decides whether your footprint is usable

A product carbon footprint is only meaningful inside a stated boundary. Two competent studies of the same product can produce very different numbers, both defensible, because one stopped at the factory gate and the other followed the product to disposal. This note covers the four decisions that determine whether the result answers the question that was asked.

First published01 September 2026
Last technical review01 September 2026
Review cycleAnnually
AuthorTechnical Directorate, Energy Up International
Technical reviewCompliance and Accreditation Officer
Reading time8 min
The two common boundaries

Where the study stops.

Cradle-to-gate

A partial CFP under ISO 14067:2018
  • Raw material extraction, transport to site, and production up to the point the product leaves the factory.
  • What a business customer usually needs for their own Scope 3 or Category 4 reporting.
  • For construction products, corresponds broadly to modules A1–A3 in EN 15804+A2.
  • Excludes distribution, use and end of life entirely.
  • Must be labelled as a partial CFP — reporting it as a full CFP is a misstatement.

Cradle-to-grave

The default full CFP
  • Everything above, plus distribution, the use phase and end-of-life treatment.
  • Required where the claim concerns the product's total impact.
  • Use-phase assumptions often dominate the result and must be stated explicitly.
  • End-of-life treatment depends on the market and its infrastructure — a single global assumption is rarely defensible.
  • The default under ISO 14067:2018 unless a partial footprint is declared.
A customer asking for "the product carbon footprint" for their supplier-data programme almost always means cradle-to-gate. A customer making a public product claim almost always means cradle-to-grave. Asking which is a two-minute conversation that prevents a re-study.
Four decisions

What determines the number as much as the data does.

  1. The declared unit

    One tonne of product, one square metre installed, one packaged unit — and the function it performs. A footprint per tonne and a footprint per unit of function can rank two products in opposite orders, and only one of them answers the customer's question.

    Decision 1

  2. The cut-off criteria

    Which inputs are excluded because they fall below a stated threshold of mass, energy or environmental relevance. The threshold is stated; it is not "things we could not find data for".

    Decision 2

  3. The allocation rule

    How impacts are divided where one process makes several products or co-products. Mass, energy content, economic value, or physical causality — each gives a different answer, and the choice must be justified against ISO 14044.

    Decision 3

  4. Data quality and geography

    Primary data for the foreground system; for the background, the database, its version and the geography it represents. A European average dataset applied to a Gulf grid is a finding, not a simplification.

    Decision 4
All four are recorded in the study report and all four are examined during verification. A study that reports only the result, with these decisions held in the modeller's head, cannot be verified at any level of assurance.
Comparability

When two footprints can be compared, and when they cannot.

Comparison between products is only valid where the declared unit, boundary, cut-off criteria, allocation rules and data vintage are equivalent. That is why Type III declarations are comparable only inside the same programme and the same product category rule — the PCR exists precisely to fix those parameters.

Outside a shared PCR, comparing two published footprints is usually invalid, and presenting such a comparison in marketing material is a claim that will not survive examination. Where a comparison is needed, the honest route is a single study covering both products on identical assumptions.

A separate point worth stating plainly: a product carbon footprint is not a CBAM figure. CBAM embedded emissions are calculated under EU rules with their own system boundary and their own treatment of precursors, and cannot be substituted with a CFP or an EPD.

Primary sources

  1. ISO 14067:2018 — carbon footprint of products, including partial CFP and CFP-PCR requirements — www.iso.org/certification.html (checked 01 September 2026)
  2. ISO 14044:2006 — LCA requirements and guidelines, including allocation procedures — www.iso.org/certification.html (checked 01 September 2026)
  3. ISO 14025:2006 — Type III environmental declarations and product category rules — www.iso.org/certification.html (checked 01 September 2026)
  4. ISO 21930:2017 — core rules for EPDs of construction products and services — www.iso.org/certification.html (checked 01 September 2026)
  5. Commission Implementing Regulation (EU) 2025/2547 — CBAM calculation methods — eur-lex.europa.eu/eli/reg_impl/2025/2547/oj/eng (checked 01 September 2026)

Editorial note. Author and technical review above are editorial functions. They are separate from the independent technical review and the decision functions required under ISO/IEC 17029:2019, which apply to validation and verification engagements and not to published articles. Nothing on this page is advice on a specific engagement, and nothing here extends or replaces the accreditation records.

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