As design and construction teams work to understand Global Warming Potential (GWP) and integrate Environmental Product Declarations (EPDs) earlier in the design process, questions often arise around how EPDs apply differently to cast-in-place (CIP) and precast concrete products.

While both fall under the broader category of concrete, the way EPDs are developed and verified, as well as the detail they contain, is fundamentally different.

An EPD is a key tool for reporting and evaluating the environmental impact of a product, particularly in the construction industry, as it focuses more on embodied carbon and transparency.  An EPD is a verified Type III environmental declaration that is based on a life cycle assessment (LCA), follows established product category rules (PCR), and is independently reviewed by a third party.  While all verified EPDs meet these criteria, they vary significantly in how the data is developed and reported, and how they should be used.

Oftentimes, specifications require EPD documents during the design stage.  For CIP projects, this typically isn’t a problem as the suppliers (ready-mix concrete, reinforcement, insulation, etc.) can provide product specific, verified EPDs for the individual materials transported to the job site. This is not the case for precast concrete.

Precast concrete is an engineered manufactured system, and its verified EPD is tied to the building design, specific production run, regional facility data, and final product configuration, including the concrete mix design and composite (concrete and reinforcement) strength. Because precast EPDs depend on actual manufacturing data, such as material availability and quantities, they cannot be verified before the product is manufactured.  This is why precast manufacturers cannot provide a verified EPD prior to manufacturing. Requiring precast EPDs too early in the project can unintentionally disadvantage precast manufacturers as compared with materials that can generate verified EPD’s during the design process such as CIP.

For precast concrete, a project verified EPD must be based on actual, project-specific production data, including:

• Raw material extraction and transportation
• Exact concrete mix design (type and quantity of cement and supplementary cementitious materials (SCMs)
• Reinforcement types and quantities
• Insulation and other consumable materials
• Plant energy consumption and waste generation

These inputs are often not finalized until fabrication is complete, making pre-production verification impossible.

Practical Alternatives During Design

To support early-stage decision-making, the precast industry relies on three primary tools:

1. Draft (Estimated) EPDs

Producers may develop draft EPDs for a project based on preliminary product designs and reinforcement assumptions.  These provide reasonable estimates but are not third-party verified.

2.  Plant/Facility Industry Average EPD

Plant/Facility Industry Average EPDs are based on data from a single manufacturing facility. They reflect average mix design, average reinforcement, average insulation, average pigment, etc. These EPDs are verified and represent a range of products rather than a single configuration.

3. Industry-Wide EPDs

Organizations such as the Precast/Prestressed Concrete Institute (PCI) publish regionalized, industry-average EPDs. These documents offer reliable benchmarking data for:

• Architectural precast
• Structural precast
• Insulated Precast Systems

These EPDs allow architects and designers to evaluate approximate embodied carbon impacts during the design phase, even when verified product-specific data is not yet available. These EPDs are verified but also represent a range of mix designs and product configurations.

Variability in Precast Design

Precast systems are inherently customizable. A single project may include multiple component types, such as wall panels, double tees, and columns, each with different geometries, reinforcement ratios, and performance requirements. Even within a single component type, design variations can significantly affect material quantities and environmental impact.

Because of the ability to customize, true product-specific EPDs cannot be generated accurately until final fabrication.

An example of a structure that is composed of multiple prefabricated components designed to work together as one unified building system.

Limitations of Mix-Only EPDs in Precast

It is also important to point out that while precast producers do not have the ability to provide an EPD for the concrete mix portion of the component only, even though they may produce their own concrete on site.  This practice is not permitted by the precast concrete PCR, which sets the rules on how precast EPDs can be developed.  However, if a precast producer purchases concrete from an off-site ready-mix producer, EPDs for those mixes would be available during the design phase (pre-production), but only if the ready-mix producer is qualified to provide a verified EPD.

Key Takeaway for Design Teams

Understanding the distinction between prefabricated product-based EPDs (precast) and mix-based or specification-based EPDs (such as CIP concrete) is critical during early project planning.

Requiring a verified, product-specific precast EPD prior to fabrication is not aligned with how precast is designed or produced. Instead, design teams should:

• Utilize industry-wide EPDs for early comparisons
• Accept draft EPDs as interim documentation
• Anticipate final, verified EPDs post-production for compliance and reporting

By recognizing this difference, project teams can make more informed, equitable material comparisons and ensure precast concrete systems are evaluated on a level playing field. Ultimately, this approach supports stronger collaboration across the project team, enabling designers, contractors, and manufacturers to work more effectively with building solution providers to achieve meaningful, measurable sustainability goals on every project.

Sustainability at Wells

Wells views sustainability as a shared responsibility with our team, design and construction collaborations, and communities.

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