Understanding GWP, A1–A3 and Lifecycle Assessment Data

Environmental Product Declarations (EPDs) are increasingly being used to support informed specification, procurement and embodied carbon assessment across the construction sector.

As environmental requirements continue to evolve, understanding lifecycle assessment data and Global Warming Potential (GWP) is becoming increasingly important when reviewing and comparing construction products.

EPDs provide independently verified environmental data using recognised international standards and lifecycle assessment methodologies.

What is Global Warming Potential (GWP)?

Global Warming Potential (GWP) measures the carbon impact associated with a product.

Within construction EPDs, GWP data helps assess the environmental impact generated throughout key lifecycle stages of a product, including raw material extraction, transportation and manufacturing.

This information supports more transparent embodied carbon comparison between construction materials and systems.

Understanding A1–A3 Lifecycle Stages

One of the primary areas reviewed within construction EPDs is the A1–A3 lifecycle stage.

These stages include:

• A1 – Raw material supply

• A2 – Transport

• A3 – Manufacturing

  
  

Together, these stages represent the embodied carbon impact associated with a construction product before installation on site.

Understanding A1–A3 data helps provide more consistent environmental comparison across products and manufacturers.

Declared Units

Construction EPDs use declared units to provide a consistent basis for comparison.

Typical declared units may include:

• per m²

• per m³

• per tonne

Ensuring products are reviewed using the same declared unit is important when comparing environmental performance data.

Lifecycle Assessment (LCA)

EPDs are developed using Life Cycle Assessment (LCA) methodologies.

Lifecycle assessment evaluates environmental impacts throughout defined lifecycle stages and provides transparent reporting using recognised international standards.

Construction EPDs are commonly developed in accordance with:

• EN 15804

• ISO 14025

• ISO 14040 / 14044

  
  

These methodologies help improve transparency and consistency across environmental product reporting.

Why Lifecycle Data Matters

Environmental data is increasingly being used to support:

• embodied carbon assessments

• product comparison

• specification decisions

• procurement requirements

• sustainability reporting

As independently verified EPD data becomes more widely used throughout construction, understanding lifecycle stages and GWP data is becoming increasingly important for informed specification.

Cellecta’s Verified EPD Programme

Cellecta’s Environmental Product Declarations are independently verified in accordance with EN 15804 and ISO 14025.

Current verified EPD coverage includes:

• ScreedBoard® 20 / 28 / 30

• HiDECK Overlay 18 / 28

• HiDECK Structural 25 / 28 / 30

• FIBREfon 8

• FIBREfon 10

Further environmental data development remains ongoing as part of Cellecta’s continued focus on transparent product information, informed specification and independently verified environmental reporting.

Further Reading

Learn how environmental product data supports:

• specification

• procurement

• product comparison

Using Environmental Product Data in Specification