Why glass EPDs vary by supply-chain stage

Glass manufacturing happens in distinct stages — float (flat) glass production, then processing into laminated, tempered, or insulated units, then final assembly into a fenestration system (a window or door). Each stage has traditionally used its own PCR, so an EPD for raw float glass says relatively little about the environmental impact of the finished window it might end up in. The National Glass Association is currently working to reduce this fragmentation for the first two stages.

Key materials typically covered

"Glass & Glazing" EPDs span several distinct product types, generally declared per stage of manufacture:

  • Flat / float glass — the base product before further processing
  • Laminated glass — bonded layers, often for safety or acoustic performance
  • Tempered / toughened glass — heat-treated for strength
  • Insulated glazing units (IGUs) — sealed multi-pane assemblies
  • Fenestration assemblies — complete window or door systems, including frame

Key standards and PCRs

In North America, the NGA PCR for Flat Glass (facilitated by NSF International) and UL's Processed Glass PCR (Part B) have traditionally covered the first two stages separately, while NSF's Fenestration Assemblies PCR — developed with FGIA, NGA, and WDMA — covers complete window and door systems. In Europe, glass products fall under EN 15804. See Product Category Rules for how to confirm the current, applicable PCR for a specific glass product.

Top EPD program operators for Glass & Glazing

A small set of program operators covers most glass-sector EPDs:

  • NSF International — facilitates the NGA's flat-glass PCR and the Fenestration Assemblies PCR
  • UL Solutions — maintains the processed-glass PCR and verifies EPDs built against it
  • Internationally: EPD International and EPD-Global operate active glass EPD programs in Europe

Notable producers of Glass & Glazing

Major flat-glass and fabricated-glass manufacturers — including European producers like Glaseksperten and CG Glass — have published product-specific EPDs across laminated, tempered, and insulated-unit product lines. Coverage varies significantly by manufacturer and product stage; check a specific producer's own published EPDs rather than assuming coverage.

Sample EPDs for Glass & Glazing

To see what an actual glazing EPD looks like, EPD-Global's public registry publishes full documents — for example, Glaseksperten A/S's EPD for Low-E triple glazing, searchable by NEPD number. In North America, NGA and NSF list published glass EPDs directly.

How to Get a Glass & Glazing EPD: Step-by-Step

Getting an EPD for flat glass, processed glass, or a fenestration assembly follows the same core process as any other construction product: choosing the applicable PCR for that stage of the supply chain, collecting primary production data, building the LCA, and having it independently verified before publication. See How to Get an EPD: Step-by-Step for the full process.

Frequently asked questions

Is float glass declared the same way as a finished window?

No — float (flat) glass, processed/fabricated glass, and complete fenestration assemblies each sit at a different stage of the supply chain and have traditionally used their own PCR, reflecting the very different manufacturing steps each represents.

What's changing with glass PCRs?

The National Glass Association (NGA) announced an initiative to combine the previously separate flat-glass and processed-glass PCRs into a single, unified framework — NGA is developing the guidance document first, then will select a qualified program operator to execute the final combined PCR.

Does a Low-E coating or number of glazing layers affect an EPD?

Yes — coating type and whether a unit is double- or triple-glazed are exactly the kind of product-specific details an EPD is meant to disclose, which is why a product-specific glazing EPD is more useful than a generic "glass" figure for comparing real options.

Who covers complete window and door assemblies specifically?

NSF International's PCR for Fenestration Assemblies, developed jointly with the Fenestration and Glazing Alliance (FGIA), the National Glass Association (NGA), and the Window & Door Manufacturers Association (WDMA).

Who verifies glass and glazing EPDs in North America?

Primarily NSF International, which facilitates the NGA's PCR for flat glass, and UL Solutions, which maintains the processed-glass PCR (Part B).

Where can I see an example of a real glass EPD?

Public EPD registries such as EPD-Global publish full glass and glazing EPD documents — see Sample EPDs below. NGA and NSF also list published glass EPDs directly.

Sources

  • National Glass Association (NGA), Product Category Rule for Flat Glass (via NSF International)
  • UL Solutions, Product Category Rule for Processed Glass, Part B
  • EN 15804:2012+A2:2019, Sustainability of construction works — Environmental product declarations — Core rules for the product category of construction products