Decoding Product Category Rules for EPD Applications

According to The International EPD^® System, thousands of new Environmental Product Declarations (EPDs) are published each year globally, reflecting a sharp rise in demand for transparent, third-party verified environmental data. However, every credible declaration relies on a strict methodological foundation called product category rules. These rules determine how environmental impacts are calculated, which life cycle stages must be included, what functional unit must be declared and how results are presented. Without adherence to these strict conditions, comparability between products is lost and verification becomes virtually impossible. For every organisation preparing an EPD application or planning to, it’s vital to understand how product category rules for EPDs work and how they are essential to your application.

What Are Product Category Rules?

Product Category Rules (PCRs) are formal documents that define how environmental impacts must be assessed and reported for a specific group of products. They act as a rulebook for creating consistent and comparable environmental product declarations. The International EPD^® System defines PCRs as documents that set out detailed requirements for:

• The product group covered

• The functional unit and declared unit

• The system boundaries of the assessment

• The environmental impact categories to be reported

• Data quality requirements

• Allocation procedures

• Reporting format and mandatory information

Rather than allowing each manufacturer to decide how to model their impacts, product category rules for EPDs ensure that every organisation within the same product category follows the same methodological approach. For example, if two insulation manufacturers both publish EPDs, the PCR ensures that both assess the same life cycle stages, apply the same impact indicators and report results in the same format. Without this structure, comparisons would be unreliable and potentially misleading.

Why PCRs Are Critical for EPD Applications

When organisations submit EPD applications, verification bodies do not simply check whether a Life Cycle Assessment (LCA) has been conducted. They assess whether the study aligns precisely with the relevant PCR. Even minor deviations can result in delays or rejection.

Ensuring Comparability Across Products

One of the primary purposes of EPDs is to enable fair comparison within a defined product category. Designers, specifiers and procurement teams rely on this comparability when making sustainability-driven decisions. Product category rules for EPD guarantee that:

• The same functional unit is applied across comparable products

• Identical life cycle stages are included

• The same environmental impact categories are reported

• Data quality thresholds are maintained

For instance, in construction products under EN 15804, modules A1–A3 (raw material supply, transport and manufacturing) must be consistently included. If one manufacturer were to omit transport impacts while another includes them, the resulting carbon footprint would not be comparable. PCRs eliminate this risk.

Safeguarding Against Misleading Claims

In recent years, regulators and competition authorities have increased scrutiny of environmental claims. PCR compliance provides a transparent and traceable methodology that underpins published environmental data. By strictly following product category rules for EPD, organisations demonstrate that:

• Their impact calculations are standardised

• Assumptions are defined and documented

• Reporting follows recognised international standards

This structured approach reduces the risk of greenwashing accusations and strengthens credibility in public procurement and investor communications.

Supporting Sustainable Procurement

Across the United Kingdom and Europe, sustainable procurement frameworks increasingly require verified EPDs. Public sector buyers, infrastructure projects and green building schemes such as BREEAM or LEED depend on comparable product data. Without the methodological consistency delivered by product category rules for EPD, these schemes would not be able to assess products fairly. PCRs, therefore, support the integrity of sustainability decision-making across entire supply chains.

Learn More: EPDs for Sustainable Construction | Tunley Environmental

Breaking Down the Structure of a PCR

Although formats vary between programme operators, most PCR documents follow a similar structure, so understanding each section is critical when preparing EPD applications.

Product Scope and Classification

This section defines exactly which products are covered. It often includes technical standards, product definitions and intended uses. Misclassifying a product can lead to selecting the wrong PCR, which may invalidate the entire process. Therefore, confirming product classification at the outset is essential.

Functional Unit and Declared Unit

The functional unit defines what is being assessed and ensures comparability. For example, it may specify:

• 1 tonne of product

• 1 square metre of material with defined thickness

• A product delivering a defined service life

If the functional unit is misunderstood or incorrectly applied, the resulting impacts will not align with PCR requirements.

System Boundaries

PCRs define whether the assessment must include:

• Raw material extraction

• Manufacturing processes

• Transport to site

• Installation

• Use phase

• End-of-life treatment

In construction, modules A, B, C and D are commonly specified. Excluding a required module would mean the LCA does not comply with product category rules for EPD.

Data Quality Requirements

PCRs establish expectations regarding:

• Primary data collection from manufacturing sites

• Use of secondary databases

• Temporal representativeness

• Geographical relevance

For example, a PCR may require primary manufacturing data less than five years old. Failure to meet these thresholds can delay verification.

Allocation Rules

Allocation becomes necessary when multiple products are produced within the same system. PCRs define how impacts must be divided between co-products, whether through mass allocation, economic allocation or system expansion. Incorrect allocation is one of the most common reasons EPD applications are returned for revision.

Reporting and Formatting Requirements

PCRs also specify how results must be presented. This includes:

• Mandatory environmental indicators

• Table structure

• Additional environmental information

• Verification statements

Even formatting inconsistencies can result in required amendments before an EPD certificate is issued.

What If No PCR Exists?

In some cases, organisations find that no PCR covers their product category. In such situations, a new PCR must be developed in collaboration with a programme operator. However, each EPD Programme operator has general PCR for construction products, in most instances this is used. If a new product category rule does need to be developed, this will involve:

• Aligning with ISO 14025

• Ensuring consistency with ISO 14040 and ISO 14044

• Consulting stakeholders

• Undergoing public consultation

• Securing programme operator approval

This process can take several months and requires technical expertise. However, it ensures that the resulting product category rules for EPD are internationally credible with sound methodology.

Reading Product Category Rules Effectively

To interpret PCRs correctly during EPD applications, organisations should adopt a structured review process. First, confirm that the selected PCR aligns with the product’s classification and intended market. Second, review the validity period to ensure it has not expired. Third, map each PCR requirement directly to the LCA modelling plan before data collection begins. These guided steps can help prevent costly revisions later in the process. Understanding PCRs also improves the ability to read EPD certificate documentation. When reviewing competitor declarations, knowledge of the underlying PCR helps assess methodological credibility and identify differences in scope or assumptions.

Learn More: How to Read an EPD

The Bottom Line

Behind every credible EPD is a detailed and highly structured framework that ensures consistency, comparability and transparency. Understanding the product category rules for EPD is a fundamental process to delivering reliable EPD data that can withstand verification and regulatory scrutiny. Early engagement with the PCRs reduces risk, prevents delays and strengthens the integrity of published data. Furthermore, digital product passports and expanding carbon disclosure frameworks are expected to further increase reliance on standardised product data. PCR compliance therefore supports long-term regulatory alignment.