Toughened Glass

Toughened Glass

Toughened glass, also referred to as tempered glass is physically and thermally stronger than normal glass. The prime function of any toughened glass is to ensure if broken for whatever reason then it breaks safely.

How Is it Made?

Tempered glass is produced by the glass being passed through an oscillating furnace at high temperatures (about 630 C) and then rapidly cooled. This procedure modifies the structure of the glass, generating a highly compressed stress surface. If the glass is shattered, the tension stored within it is released, causing the glass to break down into tiny harmless particles with blunt edges.

Benefits of Toughened Glass

  • It is much stronger than regular glass making it more durable and suitable for most uses
  • Able to withstand much a constant temperature of up to 250 degrees celsius
  • Greatly reduces the risk of injury if someone needed to break a window during an emergency (eg. during a fire break in) as it shatters into pea-sized pebbles

Disadvantages of Toughened Glass

  • It is more difficult to break in an emergency scenario
  • Due to the manufacturing process, complicated designs and shapes may not be possible
  • Cannot be cut after manufacturing, so modifications like installing a pet door may not be possible
  • Because it has a minimum thickness of 4mm, it is unsuitable for many applications.

How to Identify Toughened Glasss

There are a number of ways to determine whether your glass has been toughened –

The characteristic look of toughened glass is evident when you view it with a pair of polarized sunglasses. Dark patches or streaks may be seen across the surface, which is an indication that the glass has been tempered. During the tempering process, machine rollers created these lines in the form of dark spots on the surface.

Look at the glass edges to find out if it’s toughened – toughened glass panels have smooth and uniform edges as a result of it’s manufacturing process. If the glass isn’t tempered, however, the edges feel scratchy when touched. So, feeling for yourself is the most effective technique to determine whether or not it’s tempered.

Toughened glass can also be identified by it’s markings (see image below), although a lot of the times, it can be covered up by the window and door frames


Toughened glass marking