It only takes about three minutes for fire to shatter a standard glass pane. Fire-resistant glass, also called fire rated glass, provides extra protection during a fire by absorbing heat and preventing smoke and flames from spreading. There are different fire ratings based on how long glass will stay intact before shattering in a fire. Here are the main things to know about commercial fire rated glass.

Fire-Resistant Glass Ratings

Fire-rated glass and glazing products are designed to maintain their structural integrity under the heat and pressure of a structure fire. Performance guidelines set by Underwriters Laboratory (UL) and are based on the amount of time the glazing products can withstand intense heat. Fire-rated glass can stay intact from 15 or 20 minutes up to 180 minutes, depending on the type of glass and manufacturing process.  

Three Main Types of Fire Rated Glass

Glazing technologies are constantly evolving, but fire-resistant glass falls into three general categories:

• Wired glass – This type of glass is made using a rolling process with thin steel wire mesh embedded in the glass. Wired glass will break in two or three minutes, but unlike regular glass it will stay inside the frame when it shatters. There are usually strict building code limitations on wired glass based on the fire rating of the door or window where it is used.
• Intumescent multi-laminate glass – When additional time is needed, multi-laminate glass can withstand up to two hours of heat before failing. Intumescent sheets absorb heat and act as insulation. When layered between sheets of annealed glass, these heat-absorbing layers turn opaque in the heat and help prevent the glass from shattering.
• Intumescent gel-filled glass – In these systems, the insulating material is a gel rather than a thin, solid sheet. This intumescent gel is sandwiched between two or more sheets of tempered glass to create a thicker fire-resistant product that can withstand up to two hours of heat.

When installing fire resistant glass, it’s important to understand local building codes and the appropriate products to meet those requirements. We have spent decades working with contractors and builders to select the right fire rated products and safely install them in a variety of commercial buildings. Contact our team to get expert advice and installation on your next project.