Fire-protective glass like TGP’s FireLite® family of fire-rated glass ceramic is available with up to 90-minute fire ratings for use in openings, including windows, sidelites and transoms. Such glass defends against the spread of flames and smoke, and is suitable where protection against heat transfer is not required by code.
Advances in glazing have made it possible to design large “openings” or fire-rated windows, sidelites and transoms, that maximize both visual connectivity and daylighting while also protecting occupants from fire.
Not all windows are fire-rated. Often windows are made from standard or tempered glass held within non-rated frames, none of which offer much protection from fire and heat.
Fire-rated windows, on the other hand, must pass several tests to meet specific code requirements. To achieve a fire-rating, these tests must be conducted by an independent laboratory, such as Underwriters Laboratories (UL). The fire rating will let designers and glaziers know what sort of protection the window offers (fire-protective or fire-resistive) and the duration of said protection.
Because fire-rated windows are the sum of their components (glass and framing), their rating often is dictated by the lowest rated part within the assembly. For example, for a fire-rated window to achieve a 60-minute rating, both its glass and its frame must meet or exceed the 60-minute fire test standards.
The International Building Code (IBC) identifies where fire-rated windows are required in buildings. However, because some locations have more stringent codes, it is best practice to check with an Authority Having Jurisdiction (AHJ) to determine a project’s requirements.
For a fire-rated wall to retain its rating, any opening added to it must also be fire-rated. However, there are certain stipulations to the size and rating of the windows punched in. For interior walls rated at 60 minutes, a window that is fire-rated for 45 minutes can be installed provided it does not exceed 25% of the wall’s total area. For windows that exceed this size, their fire rating must be tested to ASTM E119 standards and be rated equal to the wall.
Fire-rated interior walls can be either fire partitions or fire barriers (such as exit access stairways, interior exit stairways, interior exit ramps, exit passageway walls, control areas and fire areas). For 60-minute fire partitions, windows rated at 45 minutes are acceptable so long as they do not exceed 25% of the wall’s total area. If they do, they must be tested to ASTM E119 standards and be rated equal to the wall. For 60-minute fire barriers, designers must choose fire-rated windows with ratings equal to the wall.
