A fire resistant casement window keeps fire and smoke from passing through an opening for a tested time. The rating comes from the whole unit: the frame, the glass, the seals, and the hardware. Fire windows are common in commercial buildings where a wall has a fire rating and the architect still needs daylight or a view.
What the rating means
Fire resistant windows are rated by the time they hold back fire and heat, commonly 30, 60, or 90 minutes in European and Asian markets, with standards like EN 1634-1 or local codes. In the US, fire windows are tested under the relevant assembly standard with limits on the glass size. The rating applies to the exact frame and glass combination, so changing the glass type or the frame profile changes the product.
Glass is the critical part
Fire resistant glass is the main cost and the main limit. Wired glass, ceramic glass, and laminated fire glass behave differently under heat, and each has a maximum tested size. Larger panels need thicker glass or a different product. Ask the supplier for the test report that names the glass construction and the maximum opening size, not a generic fire rating claim.
Frames and seals
Steel and aluminum frames are common for fire casement windows. The frame must hold the glass in place during a fire, and the intumescent seals expand when heated to block smoke. The hardware, including the handle and hinges, is part of the tested assembly, so swapping in standard hardware can void the rating.
Where they are used
Fire resistant casement windows appear in stairwells, corridors, plant rooms, and facade openings where the wall has a fire rating. They can be fixed or opening, but opening hardware must stay within the tested design. If the window faces a high wind zone, confirm the wind rating separately from the fire rating.
Send your opening size and required rating to Yesoon Door. Browse fire doors and windows and the 120-minute fire rated glass window, or read our fire rated glass guide. Yesoon Door
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