6 Types of Safety Glass

John Spacey, July 20, 2019

Safety glass is glass that is difficult to break and/or that breaks in a way that is less of a threat than standard glass. The following are common types of safety glass.

Laminated Glass

Laminated glass has a sandwich structure with two outer layers of glass and a thin layer of plastic in the middle. The plastic is bonded to the outer layers and holds the glass in place when it breaks. This produces a characteristic spiderweb pattern. As laminated glass stays intact when broken, it is commonly used for windshields and other vehicle windows to prevent passenger ejection in an accident. It is also good for heights where you don't want glass falling on people below. Possible demerits of using laminated glass as a safety glass are that it is combustible and is very difficult to break for the purposes of escape or rescue.

Laminated Chemically Strengthened Glass

Laminated chemically strengthened glass is a category of glass product that has been treated with heat and chemicals to make its exterior extremely strong. This is commonly used for smartphone screens and aircraft windows. This type of glass is often laminated to improve its strength and safety characteristics.

Tempered Glass

Tempered glass is glass that has been treated to place its exterior into a state of compression and its interior into a state of tension. This results in a strong glass that is reasonably heat resistant. Tempered glass is designed to completely break into small chunks that are thought to be less dangerous than large shards of glass. This makes it a poor choice for security glass as it can be easily and completely broken with a small puncture wound. As tempered glass completely breaks, it will not serve to hold passengers inside a vehicle during an accident. However, this characteristic may facilitate escape or rescue as the glass is relatively easily removed using a sharp object such as a screwdriver.

Acrylic Glass

Acrylic glass is not glass but is rather a translucent plastic that can be used in place of glass. This is used for specialized applications where the brittleness of traditional glass makes it a poor choice such as the window of a large aquarium. Acrylic glass is flammable and was a factor in a 1973 fire known as the Summerland disaster that took the lives of 50 people. Acrylic glass is often used in marine environments such as the windows of yachts.

Polycarbonate

Polycarbonate is another strong plastic that is commonly used as a safety glass for specialized applications such as safety goggles.

Composite Glass

Composite glass is a generic term for any glass that includes two or more structural materials. For example, laminated glass is a composite glass. Another type of composite glass, known as wired glass is commonly perceived as a safety glass but isn't particularly strong or safe as compared to laminated or tempered glass. Wired glass generally breaks more easily than regular glass. It tends to break into large shards that can be dangerous even if they are held in place by the wires. This is slowly being recognized by building codes around the world and in some cases, wired glass is being removed from schools and other government buildings.

Notes

A glass can be both laminated and tempered.

Overview: Safety Glass
Type	Glass
Definition	Glass that is difficult to break and/or that breaks in a way that is less of a threat than standard glass.
Related Concepts	Glass » Laminated Glass » Tempered Glass »