Heat treatment
Because of its smoothness, transparency and relative solidity the glass is a preferred material with many applications. But it is fragile and breakable to sharp pieces and that require to be tempered in order to improve safety.
The glass tempering is the final operation done after finishing the rest of the treatments (cutting, forming and sizing, drilling, edging etc.)
In the tempering furnace the glass is heated to 600 degrees Celsius, after that it is quickly cooled off airily.
The tempered glass is considered to be less risky than the ordinary one. It is because of its 6 time bigger strength and the fact it is breakable on small rounded pieces, in a slim chance causing injuries.
This allows the tempered glass usage in some frameless elements, for instance doors, shop windows, glass furniture etc.