Every EPD, regardless of product or program operator, moves through the same five stages. What varies is how long each stage takes and who's involved — see What Is an EPD? for what the finished document actually contains.

1. Define scope and collect data

Before any modeling happens, the manufacturer (often with an LCA consultant) defines what the declaration will cover: which specific product or product line, which facility or facilities, and which life-cycle stages will be included. This stage also involves gathering primary data — energy and material inputs, production volumes, transport distances — directly from the manufacturer's own operations. Data quality here determines the credibility of everything downstream.

2. Build the LCA model

The collected data feeds into a Life Cycle Assessment model, typically built in dedicated LCA software using background databases (like ecoinvent) to fill in impacts for upstream materials and processes the manufacturer doesn't directly measure. The model calculates results for every impact category the relevant PCR requires — not just global warming potential, but ozone depletion, acidification, eutrophication, and others.

3. Draft the declaration against the PCR

The LCA results get formatted into the actual EPD document, following the structure and disclosure requirements set by the applicable Product Category Rule. The PCR dictates which impact categories must be reported, how life-cycle modules are broken out, and what supporting information (manufacturer details, product description, scenarios assumed for the use stage) must appear.

4. Independent verification

An accredited, independent verifier — someone not involved in producing the underlying LCA — reviews the declaration against the PCR and the relevant core standard (EN 15804 or ISO 21930 for construction products). Verification checks both the LCA methodology and whether the finished declaration accurately represents it. This is what makes an EPD a Type III declaration under ISO 14025 rather than a self-declared claim.

5. Publication and registration

Once verified, the program operator publishes the EPD in its public registry, assigns it a registration number, and sets its validity period — generally five years. From this point the EPD is a citable, verifiable document that can be referenced in specifications, procurement submissions, and certification applications.

How long the process takes

Timelines vary by program operator, product complexity, and how complete the manufacturer's data is going in, but most single-product EPDs take somewhere between two and six months from kickoff to publication. Data collection and LCA modeling usually take the longest; verification itself is often the shortest stage if the declaration was drafted correctly the first time.

Frequently asked questions

Can a manufacturer produce an EPD without a consultant?

In principle yes — nothing requires a third-party consultant. In practice, most manufacturers use one because building a compliant LCA model and navigating a PCR correctly the first time has a real learning curve, and getting it wrong means rework after verification.

What happens if the verifier finds an error?

The declaration goes back to whoever prepared it for correction and resubmission. Verification is iterative rather than pass/fail on the first attempt — it's normal for a verifier to request clarifications or corrections before signing off.

Does the process differ for an industry-average EPD?

The stages are the same, but data collection happens across multiple manufacturers' facilities rather than one, usually coordinated by a trade association, which is why industry-average EPDs often take longer to produce than a single manufacturer's product-specific EPD.

Who actually owns the finished EPD?

The manufacturer (or trade association, for an industry-average EPD) that commissioned it. The program operator publishes and hosts it, and the verifier's role ends once verification is complete, but the declaration itself belongs to whoever commissioned it.

Sources

  • ISO 14025:2006, Environmental labels and declarations — Type III environmental declarations — Principles and procedures (verification requirements, clause 8)
  • EN 15804:2012+A2:2019, Sustainability of construction works — Environmental product declarations — Core rules for the product category of construction products