Tempered or toughened glass is a type of safety glass created by heating regular glass to high temperatures (650°C) and then rapidly cooling.
This process toughens it (hence the name) and makes it up to 500% more resistant to heat and impact than ordinary glass.
The toughening process’s primary goal is to improve the glass’s durability and thermal strength.
It is important to note that this type of glass cannot be re-cut after it has been toughened; it must be cut prior to toughening.
This means that you won’t be able to modify the glass for purposes such as installing a pet door.
Toughened glass is frequently used as doorways, stairwells, sliding doors, standard windows, and floor-level windows in buildings and houses. It is used because they will not be a source of concern in the event of an accidental impact.
Look for a stamp in the corners of the glass indicating that it is toughened or tempered.
When you run your hand across the edge of the sheet, you can also inspect the edges of the glass because tempered glass has smoother edges than regular glass.
This is one of the most noticeable differences between annealed and tempered glass.
Toughened glass is up to five times stronger than regular annealed glass and can withstand surface compression of more than 10,000 psi. It is also highly resistant to thermal breakage.
Toughened glass breaks into small pebble-sized pieces, as opposed to regular glass, which breaks into dangerous shards.
Toughened glass is typically 30% more expensive than regular annealed glass, but it is still considered a less expensive alternative to laminated glass, which is typically twice the price of toughened glass.
Toughened glass is widely available in thicknesses ranging from 4mm to 10mm.
Toughened glass in thicknesses of up to 20mm can be ordered.
In public areas, we generally recommend 6mm toughened glass as a bare minimum.
Both laminated glass and toughened glass are classed as A grade safety glass and the one to pick will depend on the application.
Toughened glass is more impact resistant than laminated glass, but laminated glass is more resistant to penetration.
In general, we recommend toughened glass for windows and doors in homes and laminated glass for public areas such as shopping centres and office buildings.
Elias Chahine is the director of Gusto Emergency Glass Replacement and has many years in the glass repair and construction industry