Quick answer: Fire-rated glazing is glass tested to maintain integrity during a fire for a specific duration — 20, 45, 60, 90, or 120 minutes. Required at fire-rated walls, exit stairs, occupancy separations, and openings in rated assemblies. Common products: SuperLite II XL, FireLite (Pilkington), Pyrostop, and Pyran by SCHOTT. The required rating depends on the wall's fire rating per IBC and FBC.
Fire-rated glass is engineered to survive direct flame contact and high temperatures for a specific duration. Products use different technologies: wired glass (legacy, declining use), ceramic glass (high temperature resistance), intumescent interlayer (expands when heated to block flame transmission), and tempered with gel layer (water-cooled glass technology). The rating measures both integrity (no flame passage) and, in higher ratings, insulation (limits heat transfer to the unexposed side).
20-minute: smoke and draft control doors, corridor walls. 45-minute: shaft walls, vertical exits in low-rise. 60-minute: fire barriers, exit stair enclosures in high-rise. 90-minute: occupancy separations between certain occupancy types. 120-minute: most demanding rating, typically used in high-rise exit stair enclosures and area separation walls.
Integrity-only glazing prevents flame and smoke passage but allows heat to transmit through. This is acceptable for many applications. Insulation-rated glazing (EI) limits heat transfer on the unexposed side — required where occupants must use the space adjacent to the rated assembly during fire (exit stairs, vestibules).
FireLite Plus (Pilkington): 20-90 min, integrity-only. SuperLite II-XL (SAFTI FIRST): 20-120 min, integrity-only and EI options. Pyrostop (Pilkington): 60-120 min, EI rating, intumescent. Pyran (SCHOTT): 20-180 min, ceramic, integrity-only. Each has different size limitations and cost.
Fire-rated walls (rated per IBC Table 716.1(2)) require fire-rated glazing in openings. Exit stair enclosures, area separation walls, occupancy separations, and corridor walls all may require rated glazing depending on the building's construction type and occupancy classification. Always verify with project code official before specification.
Fire-rated glazing is significantly more expensive than standard tempered or laminated commercial glass. 20-min rated glass: 4-8x clear tempered cost. 60-min: 8-15x. 90-120 min EI: 15-30x. Limit fire-rated glazing to where actually required by code.
Fire-rated glazing is glass tested to maintain integrity during a fire for a specific duration — typically 20, 45, 60, 90, or 120 minutes. It's required in commercial buildings at fire-rated walls, exit stair enclosures, and occupancy separations per IBC and FBC.
20, 45, 60, 90, and 120 minute ratings are commercially standard. Each has integrity-only (E rating) and integrity-plus-insulation (EI rating) variants. EI is required where heat transfer to the unexposed side must be limited.
Fire-rated glazing is significantly more expensive than standard commercial glass. 20-minute rated: 4-8x clear tempered cost. 60-minute: 8-15x. 90-120 minute EI: 15-30x. Limit to where code actually requires.
Wired glass is still allowed by IBC and FBC for some applications but is restricted near doors and in safety-glazing locations because it doesn't meet impact safety standards. Modern fire-rated alternatives have largely replaced wired glass on commercial work.
Fire-rated glazing is tested for fire resistance. Impact-rated glazing is tested for windborne debris resistance. They're different code requirements addressing different hazards. Some products meet both (fire + impact), but the testing is separate.
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