Fire-resistant windows are building fire-resistant partitions constructed with steel, wood, or steel-wood composite materials for the window frame and sash, fitted with fire-resistant glass and fire-resistant hardware. Their purpose is to form an effective fire barrier during a fire, preventing the spread of fire and smoke, while also providing ventilation and lighting.
Fire-resistant windows can be classified by opening method into fixed fire-resistant windows (sashes cannot be opened) and operable fire-resistant windows (sashes can be opened and equipped with a sash opening and closing control device). Operable fire-resistant windows are typically casement windows.
Based on fire resistance performance, fire-resistant windows can be classified into insulated fire-resistant windows (Class A), partially insulated fire-resistant windows (Class B), and non-insulated fire-resistant windows (Class C). Fire resistance performance is expressed in minutes (min), for example, A1.50 (fire resistance integrity ≥90min), A1.00 (≥60min), A0.50 (≥30min), etc. After the implementation of the new standard, the original designations of "Class A, B, and C" will no longer appear as official codes in model designations, but may be used as supplementary information in the remarks section.
Fire-resistant windows are mainly used in building exterior wall openings or skylights where fire separation distances are insufficient; in locations on interior firewalls or fire-resistant partitions where observation and light retention are required; and in exterior wall openings where it is necessary to prevent the vertical spread of fire along the exterior walls. Fire-resistant windows installed on firewalls and fire-resistant partitions should have non-openable window sashes or a function that automatically closes in case of fire.