Tempered Glass / Safety Glass
Tempered glass is a type of safety glass that is specially treated to make it stronger and, more importantly, safer if it breaks.
Why Is It Used?
Instead of breaking into large, sharp pieces like ordinary annealed glass, tempered glass is designed to break into many smaller pieces that are less likely to cause serious injury. Tempered glass is primarily a life-safety feature, not an energy-efficiency upgrade.
Where Is Tempered Glass Commonly Required?
In many doors and patio doors.
In certain windows or sidelights located near doors.
In hazardous locations near bathtubs, showers, hot tubs and similar wet areas.
In certain large or low windows close to walking surfaces.
In certain locations near stairs, landings and ramps.
Not every window near a door, every low window, or every bathroom window automatically requires tempered glass. The complete location and applicable code requirements determine whether safety glazing is required.
How Can You Identify Tempered Glass?
Tempered glass typically has a permanent manufacturer's safety marking, sometimes called a bug, located near a corner of the glass.
Can Existing Glass Be Tempered?
No. Glass must be cut and prepared to its final size before it goes through the tempering process.
What Happens During Window Replacement?
An older window may have ordinary glass in a location where current requirements call for safety glazing. When that window is replaced, tempered or other approved safety glazing may be required even though the original glass was not tempered.
Related Window Terms
Insulated Glass Unit • Low-E Glass • Egress Window • Window Installation • U-Factor • SHGC