What is an Environmental Product Declaration (EPD)? A Complete Guide

In today’s world of sustainability and climate awareness, understanding the environmental performance of products is no longer optional. Both manufacturers and buyers need transparent, credible information about how products impact the environment. One of the most reliable tools for this is an Environmental Product Declaration (EPD).

In this guide we will explain what an EPD is, why it matters, how it is developed, and how we use EPDs in practice. You will also learn about key standards (such as ISO 14025 and ISO 21930), product category rules (PCRs), and what defines a robust, trusted environmental product declaration.

Table of Contents

1. What is an Environmental Product Declaration?
2. Why EPDs Matter: The Value of Transparency
3. Key Standards: ISO 14025, ISO 21930 and PCRs
4. Life Cycle Assessment (LCA) & Product Carbon Footprint
5. The EPD Development Process
6. Common Use Cases: Construction Products & Green Building
7. Best Practices for Adoption & Verification
8. Summary: The Future of EPDs

1. What is an Environmental Product Declaration (EPD)?

An Environmental Product Declaration (EPD) is a Type III environmental claim document which provides quantified, verified information on the environmental impact of a product throughout its life cycle. Unlike marketing claims or labels, EPDs are based on real data, follow international standards, and are third party, meaning that they are verified by independent bodies.

In simple terms, an EPD answers the question: What is the environmental cost of this product – from cradle-to-grave or cradle-to-gate – in terms of carbon, resource use, emissions, waste, and more?

2. Why EPDs Matter: The Value of Transparency

• Better decision making: An EPD gives architects, designers, contractors and consumers data to compare construction products or other products on metrics such as product carbon, embodied emissions, resource depletion, etc.
  
• Regulatory & certification compliance: Many green building schemes (such as LEED, BREEAM) and procurement policies increasingly demand EPDs that conform to the right standards.
  
• Competitive advantage: Products with credible environmental product declarations can stand out in tenders, especially where supply chain transparency and carbon footprint reduction are priorities.
  
• Life cycle optimisation: Using life cycle assessment tools helps identify hotspots (for example, high-impact materials or inefficient processes) and reduce environmental impact.

3. Key Standards: ISO 14025, ISO 21930 and PCRs

To ensure consistency, comparability and credibility in EPDs, several international standards are central:

Standard	Purpose
ISO 14025	Sets out the principles, procedures and requirements for Type III environmental declarations. It ensures that EPDs are transparent, independently verified, and follow consistent formats.
ISO 21930	Focuses on the core rules for environmental product declarations of construction products and services. It complements ISO 14025 by giving extra guidance specific to construction, ensuring that product category rules (PCRs) reflect attributes like modules A1-C4, material reuse, and traceability.
Product Category Rules (PCRs)	PCRs define the specific rules for a product category (for example, insulation materials, concrete products, roofing membranes etc.). They specify what data must be included, the system boundaries, functional units, and which environmental impact categories apply. Without PCRs, product declarations cannot be reliably compared.

Other relevant standards include ISO 14040 / ISO 14044, which define how to conduct a life cycle assessment (LCA), required as input for an EPD. 

4. Life Cycle Assessment (LCA) & Product Carbon Footprint

An EPD is grounded in a life cycle assessment (LCA). The LCA examines a product across stages such as raw material extraction, manufacturing, transport, use, maintenance, and end-of-life. The outputs of LCA feed into various impact categories including climate change (often expressed as product carbon footprint), resource depletion, toxicity, etc.

For example, LCAs are used not only to prepare EPDs but also to evaluate whole projects, looking at environmental impacts over the full cycle of use, maintenance, and disposal.

5. The EPD Development Process

Here is a typical step-by-step process to create a credible, standards-compliant EPD:

1. Define scope & goal: Decide whether the EPD will be cradle-to-gate, cradle-to-grave or somewhere in between. Set functional units.
   
2. Select the relevant PCR: Identify relevant product category rule that matches the product type. The PCR defines how to do the LCA, what data to include, system boundaries, etc.
   
3. Conduct LCA: Collect life cycle inventory (LCI) data, model environmental flows, emissions, resource inputs etc.
   
4. Life Cycle Impact Assessment (LCIA): Translate the inventory data into environmental impacts like global warming potential, resource depletion, human toxicity etc.
   
5. Draft Environmental Product Declaration: Write up the environmental product declaration document including product description, data, impact categories, LCA methodology, assumptions.
   
6. Verification / third-party review: Engage an independent reviewer to ensure compliance with relevant standards and accuracy of data.
   
7. Publish & maintain: Make the EPD publicly available and update periodically (often every five years or if product or process changes substantially).
   

This process ensures that product declarations are credible, comparable, and useful for decision makers.

6. Common Use Cases: Construction Products & Green Building

Construction products are among the most frequent users of EPDs. Here is why:

• In green building projects, materials are selected not only for strength and cost but increasingly for embodied carbon and environmental footprint.
  
• Builders and specifiers often require EPDs that comply with ISO 21930 (for construction products and services) or EN 15804 (in Europe) so that comparisons are fair.
  
• Public procurement and government-led infrastructure projects often mandate EPDs to meet policy goals for carbon footprint reduction, circularity, and supply chain transparency.
  

Furthermore, EPDs help in:

• Green building certification (LEED, BREEAM etc.)
  
• Supply chain management, helping suppliers align data collection, PCRs, and LCA practices
  
• Risk mitigation, particularly from regulatory or financial risks linked to emissions reporting

7. Best Practices for Adoption & Verification

To ensure your EPD or adoption of EPD data truly adds value, follow these best practices:

• Use PCRs that are relevant and current; ensure they cover the appropriate product category and environmental indicators.
  
• Ensure full transparency of inputs: raw materials, energy sources, transport, maintenance etc. A great EPD is hard to compare if one product includes lifecycle stages that others do not.
  
• Verification by a third party is essential. Without external review, an environmental product declaration risks losing credibility.
  
• Use consistent functional units when comparing products. For example per kg, per m², per seat per year etc., depending on product type.
  
• Update EPDs over time, especially when product composition, manufacturing processes, or supply chain change.
  
• Embed EPD thinking early in the design and procurement process. Early identification of carbon footprint hotspots leads to better decisions.

8. Summary: The Future of EPDs

An environmental product declaration is a powerful tool for measuring, communicating and managing environmental performance. Rooted in life cycle assessment, guided by standards like ISO 14025 and ISO 21930, and structured through product category rules, EPDs are rapidly becoming central to how we think about sustainability, particularly in the built environment.

At Cerclos we believe embracing EPDs, fostering supplier engagement, adopting third party verification, and using EPDs in green building, construction, and infrastructure projects will be essential. For any organisation wanting to lead in environmental performance, EPDs are not just useful; they are indispensable.

Key Terms Glossary

Term	Definition
Life Cycle Assessment (LCA)	A systematic analysis of environmental impacts across all life cycle stages of a product.
Product Category Rule (PCR)	Rules defining how to conduct an LCA and prepare an EPD for a specific category of product.
Third Party / Verification	Independent review to ensure compliance with standards.
ISO 14025	Standard for Type III environmental declarations.
ISO 21930	Standard specifically for construction products and services.