Subcategory PCRs are typically developed by industry associations or collaborations between manufacturers and stakeholders for a given product category. Product categories are typically established based on a Construction Specifications Institute (CSI) MasterFormat designation or standard manufacturing specifications such as those from ASTM International or the American Association of State Highway and Transportation Officials (AASHTO).
EPDs can be developed for one or more products and for one or more manufacturers. EPDs can be categorized as plant- or producer-specific declarations or as industry-average declarations. Those EPDs classified as “plant-specific” report environmental impacts as an average of:
- One product from one manufacturer’s plant; or
- An average product from one manufacturer’s plant.
“Producer-specific” EPDs report environmental impacts as an average of:
- One specific product from several of a manufacturer’s plants; or
- An average product from several of a manufacturer’s plants.
EPDs that are considered industry-average declarations report environmental impacts as an average of:
- One specific product from several manufacturers’ plants; or
- An average product from several manufacturers’ plants.
To set requirements related to low-embodied-carbon materials that qualify for IRA funding, draft federal agency requirements are setting a maximum GWP value related to an industry-average EPD. In order to qualify as a low-embodied-carbon material and be selected for projects that GSA and other federal agencies are using IRA funds, manufacturers must create plant- or product-specific EPDs to show the GWP of their products.
However, basing product selection on one potential environmental impact category, such as GWP, can increase other environmental impacts and the GWP of other lifecycle stages. In the worst case, this may increase the total GWP of a structure. These concerns are highlighted in the next section with examples related to a precast concrete and an LCA case study.
Seeing the whole picture
There are many sustainable design and construction practices that are not reflected in cradle-to-gate EPDs. For example, precast concrete uses recycled materials, including industrial by-products (fly ash and slag cement) and aggregate fillers (ground limestone), which can reduce the need for portland cement, and which is reflected in an EPD. However, precast concrete is also manufactured locally, reducing transportation impacts to the construction site, and it also reduces construction waste, minimizes site impacts, allows for quicker assembly due to being manufactured off site in a controlled environment. All these attributes are not captured in a cradle-to-gate EPD for precast concrete.
