Tempered vs Annealed Glass

There are pros and cons to each, and each customer is different based on the use of the glass.

Tempered vs Annealed Glass
Tempered vs Annealed Glass

This is one of the most common questions that we get at Floyd Glass & Window.
There are many applications for tempered glass. It is used commercially in glass doors that have no frames. The windows in the passenger sides of cars use tempered glass to increase safety.

Annealed glass can be used in many situations. If a window is in a low-traffic area where safety is not a concern, annealed glass may be the best option because it remains cheaper than tempered glass. But many states have adopted building codes where tempered glass is required. For instance, any glass window within two feet of an open door must be tempered.

When glass is annealed, it is slowly cooled to relieve any internal stresses. When not annealed, glass is more likely to crack when exposed to temperature changes. Unlike tempered glass, traditional annealed glass will break off into large, sharp shards when broken. This can pose obvious safety risks. Care should be taken when choosing locations to install annealed glass. Annealed glass is a great fit for table top glass, cabinet door glass and basement windows.

Tempered glass is also called toughened glass. Unlike annealed glass, tempered glass breaks into small, square pieces when broken. This makes it less likely to lacerate a person that comes into contact with it. Tempered glass is one of the hardest types of glasses, several times harder than most others, including annealed glass. Creating tempered glass involves the use of chemicals and heat to give it its properties. These treatments balance the internal stress rating of the glass. The downfall of Tempered Glass (as you will see in the video below) are the edges of the glass. Because of the heating and cooling process that the glass goes through to become tempered, the edges are the weak point. Meaning, if metal comes in contact with the glass it is highly likely it will blow: no one will get hurt, but you will now be in the market for a new piece of glass. Tempered Glass also can not be cut. Once it starts getting cut, it will explode into a thousand pieces.
Frameless Shower Doors, Windows within 18” from the ground, Windows above a bathtub/Shower, glass within a certain distance of a doorway all must be tempered by State Law. Because of the edges, Floyd Glass & Window recommends Annealed glass for most table tops.

Tempered glass is more expensive than annealed glass because it has to go through more processes in its creation.

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