Fire-resistive glazing
Fire-resistive glazing adds an extra layer of protection by also limiting the transfer of heat through the glass. This safeguard makes it suitable for use in walls, doors, and other fire-rated assemblies designated to block the passage of excessive heat, hot gases, or flames.
In Canada, fire-resistive glazing satisfies CAN/ULC-S101, Fire Endurance Test of Building Construction Materials—the fire-resistance test standards for walls. It can carry fire ratings up to 120 minutes, pass the fire and hose stream tests, block significant amounts of heat, and protect against human impact. For police stations and other at-risk buildings, it is available with bullet resistance ratings.
Given these performance characteristics, fire-resistive glazing is suitable where building codes require an assembly designated “fire resistant” to enclose a space, including wall applications requiring a 60-minute or greater fire rating that must meet temperature-rise criteria.
While fire-resistant glass technology varies by manufacturer, the systems typically provide the necessary fire resistance in the same way: multiple layers of glass sandwich an inert material that turns opaque and foams up during a fire. The internal reaction allows the glass to remain relatively cool on the non-fire side of the wall, protecting building occupants and valuables from flames, smoke, and high heat for its designated fire rating period.
Remarkably, the multi-laminate makeup of fire-resistive glazing still offers nearly the same level of visual clarity as ordinary float glass. Further, since it is not restricted to 25 per cent of the total wall area, it can bring exceptional clarity and visibility to floor-to-ceiling and wall-to-wall designs requiring a high level of fire protection.
In application
Before moving forward with specification, it is important to recognize which type of fire-rated glazing is suited for use in particular applications, such as doors, windows, or glazed walls.
Doors
Fire-protective and fire-resistive glazing products can be used in doors where glazing is necessary or desired, and where fire and life safety is a concern. Each type of glazing has a different set of fire and life safety performance criteria.
Fire-protective glazing is available with 20 to 180-minute fire ratings for door assemblies. It is subject to area and size limitations depending on whether the application requires meeting temperature-rise criteria. For example, fire-protective glass can typically be used in the maximum size tested (as tested by an independent testing agency) in fire doors requiring a 20- or 45-minute rating. Comparatively, for code applications requiring doors with temperature-rise criteria, such as those in exit enclosures and passageways, fire-protective glass is typically limited to 0.0645-m2 (100-si) lites.
Fire-resistive glass is suitable for use in temperature-rise door applications without any size limitations. Its performance is critical in such applications, as the temperature rise on the non-fire side of the door assembly may not exceed 232 C (450 F) above the ambient temperature at the end of the first 30 minutes. This helps ensure occupants may still pass by a door to exit a building if temperatures reach high levels on the non-fire side of the door.
