EPiC database - Toughened glass

This material is part of the free Environmental Performance in Construction (EPiC) Database. The EPiC Database contains embodied environmental flow coefficients for 250+ construction materials using a comprehensive hybrid life cycle inventory approach.

Toughened, or tempered glass is made from flat glass that has been strengthened. Flat glass is made from a combination of silica, soda, lime, dolomite and aluminium oxide. The raw materials are melted at high temperature and the molten glass is then formed into flat glass using a variety of processes. A floating process, where the molten glass is floated on a bed of tin, is most common for manufacturing window glass. The glass is then gradually cooled (annealed) and cut to size.

To produce toughened glass, the flat glass is then heated and rapidly cooled, increasing compressive stress on the outer surfaces of the glass. This produces glass that is 5 times stronger than standard flat glass.

Toughened glass is commonly used for windows, glass doors, balustrades, shower screens and pool fences. It provides added safety over flat glass as when broken, the glass shatters into small even pieces.