Glass

Flat glass is made from molten material consisting of a combination of silica sand, limestone, soda ash, dolomite and glass cullet spread onto sheets on a plane to produce flat, float, rolled, plate or sheet glass. Flat glass is sometimes bent after production of the plane sheet. The general term “flat glass” describes all glass produced in a flat form, such as float glass, sheet glass, plate glass and rolled glass. Flat glass can be heat- or surface-treated to make processed glass, or built into assemblies such as insulating glass units (IGUs), laminated glazing units, and vacuum insulating glazing. Flat glass assemblies are often part of curtain walls, storefronts, transparent walls, window units, skylights, canopies, doors, and solar panels.

Construction product assemblies (such as processed glass fabricated from flat glass, or insulating glass units containing flat glass) qualify for IRA funding if at least 80% of the assembly’s total cost or total weight is comprised of materials that meet these Requirements. For purposes of the calculation, the glazing assembly on curtain wall, storefront, or punch window conditions includes only the assembly components of the glazing unit (e.g., an IGU or laminated glazing unit). Glazing assembly components include flat glass lites, any laminate interlayers (e.g., PVB), any fritting or internal IGU shading components, spacer and created airspace, desiccant, and perimeter edge seals. Assembly components exclude adjacent materials from the glazing unit assembly calculation, such as window sashes and framing, gaskets, sealants, seals, air vapor barrier, and structural connections. Those adjacent materials may be covered as expenses necessary to acquire and install approved products, materials, and assemblies.

GSA IRA LEC material requirements

GSA IRA limits for low embodied carbon glass

(EPD-reported GWPs, in kilograms of carbon dioxide equivalent per metric ton — kgCO₂e kg/t)

Glass product category1	Top 20% limit	Top 40% limit	Better than average limit
Flat glass (per metric ton)	1,331	1,370	1,401

Compliance documentation

A product-specific Type III (third-party verified) EPD that: (i) is based on the PCR used to develop these limits: the NSF International/National Glass Association Flat Glass PCR (9/2020, version 2.0; or 3/2013, version 1.0) [PDF]; and (ii) conforms with ISO 14025 and ISO 21930. Where feasible, EPDs must also be based on supply chain-specific data for associated unit processes, such as facility-specific data for processed glass’s upstream glass plants, rather than industry or manufacturer average data. If an EPD containing facility-specific data for the material’s most greenhouse-gas intensive processes is unavailable, an EPD without such data that meets Compliance Documentation criteria (i) and (ii) is sufficient.

ENERGY STAR Energy Performance Score for supplying cement plant, the manufacturing plant name(s) and location(s), and the data period of the Energy Performance Score(s) at the time of purchase. For more information, please see ENERGY STAR Energy Performance Scores explained below.

ENERGY STAR Energy Performance Scores explained

ENERGY STAR Energy Performance Scores show how efficiently a manufacturing plant uses energy on a 100-point scale. A score of 50 reflects average performance, 1 shows poor performance, and 100 reflects highest performance.

Contractors obtain Energy Performance Scores by requesting producers of cement, glass, asphalt mix, and steel (from integrated mills only) to provide the score. Or, contractors may request it from material suppliers (e.g. concrete producers).

Manufacturers of cement, glass and steel (from integrated mills only) produce a plant’s score by inputting 12 months of energy and production data in the industry-specific Energy Performance Indicator tool available at www.energystar.gov/epis. The score will show on the Statement of Energy Performance section of the EPI.

Energy Performance Scores can currently be produced for cement, flat glass, and integrated steel mills.

Footnotes

1. Based on input from the glass industry about inconsistent data from the limited set of processed glass and insulating glazing unit EPDs, GSA is only issuing GWP limits for unfabricated flat glass at this time.