Environmental product declarations: a guide for construction teams

An environmental product declaration, or EPD, is a standardized report of a product's environmental impact across its life cycle. Think of it as a nutrition label for a building material. It doesn't say whether a product is good or bad, but it presents the facts in a consistent format so that products can be compared.

EPDs sit behind most credible carbon estimates, green building credits and low-carbon procurement requirements, so it pays to know how they work.

What an EPD contains

Every EPD is based on a life cycle assessment (LCA) of the product. Construction EPDs follow international standards (ISO 14025, together with ISO 21930 or EN 15804), and each is prepared under product category rules (PCR) that set out how products of that type must be assessed. A typical EPD includes:

• The product and manufacturer, including which plant or plants it covers.
• The declared unit, such as one cubic metre of concrete, one tonne of steel, or one square metre of insulation at a given thermal resistance.
• The life-cycle stages covered, usually at least the product stage (A1–A3): raw materials, transport to the factory and manufacturing.
• Impact results, including global warming potential (GWP) in kilograms of CO₂-equivalent, alongside other indicators such as acidification and smog formation.
• Validity and verification: the period the EPD is valid for, and the independent third party that verified it.

Product-specific and industry-average EPDs

EPDs come in different kinds, and the difference matters:

• Product-specific EPDs cover one product from one manufacturer, sometimes from a single plant. They're the most accurate.
• Industry-average EPDs are published by industry associations and represent a typical product across many manufacturers. They're useful early in design or when no specific EPD exists, but they can't tell you whether the product you're buying is better or worse than average.

Where you can, use product-specific EPDs for the materials that drive most of your footprint. That's the only way lower-carbon choices show up in your numbers.

How to read one without getting lost

EPDs can run to dozens of pages. For most construction decisions, you need five things:

1. Check it's valid and verified. Look for the expiry date and the name of the verifier.
2. Check the declared unit. Only compare products with the same unit and performance. A tonne of one insulation isn't comparable to a square metre of another at a different thermal resistance.
3. Check the stages. Make sure you're comparing A1–A3 with A1–A3.
4. Find the GWP figure. This is the number that feeds your carbon estimate.
5. Check the product category rules. Products assessed under different rules may not be directly comparable.

Using EPDs on your projects

• During design, compare EPDs for major materials to find lower-carbon options, especially concrete mixes, steel, insulation and glazing.
• In procurement, ask for product-specific EPDs in tenders and purchase orders, and consider setting maximum GWP values for key materials.
• On delivery, link each EPD to what actually arrived on site, so your as-built carbon estimate reflects real products. Material traceability makes this routine.
• In reporting, keep EPDs with your carbon figures so anyone reviewing them can see the source.

Limits to keep in mind

An EPD describes a product's impact. It doesn't certify that the product is environmentally friendly. Results depend on the data and assumptions behind the LCA, so small differences between two EPDs may not be meaningful. EPDs also cover the product, not how it's used: a low-carbon material specified in excess can still produce a high-carbon building.

An EPD doesn't say whether a product is good or bad. It tells you the facts in a format you can compare.

Used well, EPDs turn carbon from a rough estimate into something you can measure, compare and act on. Our guide to carbon footprint estimation shows how they fit into the full calculation.