Commercial Grade Firerated Glass

Commercial grade fire-rated glass has a one-inch minimum thickness and can be reinforced by fiberglass or polystyrene with a ten-inch spray-foam liner. When heat is applied to the fire-rated glass through a standard hose stream test, it should yield a radiant heat value of approximately seven thousand and. If there are gaps in the fireproof lining, however, or if the commercial grade glass does not meet the required one-inch minimum thickness, it will be deemed fire-rated glass. Any gaps in the fire-rated lining require that the material be treated with an insecticide before installation.

Fire rated glass must pass several tests to qualify for commercial use: thermal impact ratings, tensile impact ratings, and escape time. Thermal impact ratings are expressed as a percentage of total incident temperature. A thermal impact rating of zero indicates that the glass would decrease in temperature after one second of exposure to the heat of fire. A thermal impact rating of six indicates that even the thickest sheet of glass would not reduce in temperature after one second of exposure. Escape time is a calculation of the time taken to exit a structure during a fire.

Tempered glass has low to zero escape times but is still rated with a high impact rating. Glass with a high impact rating is more difficult to heat, and decrease in temperature than non-tempered glass, but it is more resistant to indentation. Glass with a high thermal conductivity and/or fire rating is more resistant to gases emitted during the fire but has lower energy loss through combustion. Allowing for proper ventilation, and escape routes, as well as providing adequate escape routes in case of emergencies, will allow for a safer building.