Product carbon footprints, LCA and EPDs explained

Customers, architects, procurement teams and regulators increasingly ask for the environmental footprint of individual products, not just company totals. Three related tools answer that request: the product carbon footprint, the life cycle assessment and the environmental product declaration. Here is how they differ and how to produce them.

Life cycle assessment (LCA)

A life cycle assessment quantifies the environmental impacts of a product across its life cycle, from raw material extraction through manufacturing, distribution and use to end of life. It is governed by ISO 14040 and ISO 14044, which set out four phases: goal and scope definition, life cycle inventory analysis, life cycle impact assessment and interpretation.

An LCA covers many impact categories, not only climate change. Typical categories include acidification, eutrophication, ozone depletion, photochemical ozone formation, resource depletion and water use.

Product carbon footprint (PCF)

A product carbon footprint is a focused application of life cycle thinking that covers only greenhouse gas emissions. ISO 14067 sets out requirements for quantifying and reporting it, and the GHG Protocol Product Standard provides similar guidance.

PCFs are often calculated cradle-to-gate, covering everything up to the point the product leaves the factory, because that is what a customer needs for its own Scope 3 inventory. Cradle-to-grave footprints add distribution, use and end of life.

Environmental product declaration (EPD)

An environmental product declaration is a standardised, third-party verified document that reports LCA results for a product. EPDs are Type III environmental declarations under ISO 14025. They are based on product category rules (PCRs), which define how the LCA must be done for a given product group so that declarations within the same category are comparable.

For construction products, EN 15804 provides the core rules, and results are reported by life cycle modules: A1 to A3 for the product stage, A4 and A5 for construction, B for use, C for end of life and D for benefits beyond the system boundary. EPDs are published through programme operators and are typically valid for five years.

Why demand is growing

• Green building rating systems award credits for using products with EPDs.
• Public procurement increasingly sets limits on embodied carbon.
• Customers need supplier-specific data to calculate and reduce their Scope 3 emissions.
• Trade measures such as the EU CBAM require embedded emissions data for certain goods.
• Product-level data allows companies to market and price lower-carbon products credibly.

The data behind a good footprint

The quality of a PCF or EPD depends on primary data from the plant: energy and fuel consumption, raw material inputs and their origins, process emissions, transport, packaging, waste and yields. Background data for upstream materials comes from LCA databases.

Allocation is often the hardest methodological question. When a plant makes several products, or a process yields co-products, emissions must be allocated between them using rules set by the standard and the PCR. Document every allocation decision.

Producing footprints efficiently

Producing one EPD by hand is manageable. Producing footprints for a whole product range, and updating them each year, is not. Companies that do this well:

1. Build a model of their production processes that links plant data to products.
2. Use the same validated plant data that feeds their corporate GHG inventory.
3. Reuse background data and allocation rules consistently.
4. Recalculate footprints automatically when plant performance changes.
5. Keep the evidence needed for third-party verification.

How NCV helps

NCV produces LCAs, product carbon footprints and EPDs to ISO 14040/44, ISO 14067 and EN 15804, including verification support. Because SustainOS already holds a company's validated energy, materials and emissions data, product footprints can be updated from live plant data, so they reflect improvements as they happen.