Tempered glass is (flat and bent), on a bend and hit 5-6 times stronger than rough with the same thickness and configuration, and thermal stability is considerably higher. The surface of such glass can withstand pressure of more than 10 000 pa (for 6 mm glass) that meets the requirements of standard EN 12150, as well as GOST 30698-3000 “Tempered glass”.
In the case of destruction, tempered glass breaks into small and obtuse pieces that are incapable to cause serious harm. Therefore tempered glass is considered “safe”. Architects prefer to use such glass on projects reducing the risk of sudden destruction of glass designs.
The scope of tempered glass:
- flat skylights, conservatories, garden houses, greenhouses;
- facade and structural glazing, office partitions, glass doors, frameless balcony glazing, stained glass windows and railings, canopies, staircases;
- glazing of different types of vehicles: passenger cars and trucks, trams, trolley buses, agricultural and road machinery, rolling stock railway, river and sea vessels of fleet;
- the production of glass furniture: shelves, racks, shop windows, bookstands;
- manufacturing of observation windows in stoves, domestic gas stoves.
Tempered glass is made of sheets of brushed, polished or patterned glass on special tempered machineries (in furnace of temper). If necessary, the required cuts, holes are first made in glass, edges are handled because the finished tempered glass cannot be cut, drilled and subjected to other types of mechanical processing. The tempered glass in a way is similar to steel temper. First, it is heated above the softening temperature of 650-700° C and then quickly cooled in the air blasts. Upon cooling the first surface layers of glass are hardened. Upon cooling of inner layers residual compressive pressure appears. These tensions provide mechanical strength and heat resistance of glass. Broken tempered glass breaks into small sharp fragments that the requirements of quality standards regulate.
Thus, when the control destructing with the sharp hammer weighing 75 grams, tempered glass must have at least 40 fragments in square of size 50×50 mm or 160 fragments in square 100×100 mm. The most vulnerable place of tempered glass is its edges. When mounting structures it is necessary to protect its edges from bumps, scratches and other damage. The light transmittance of transparent tempered glass is not less than 84 %. The glass is hardened using special equipment.
Architectural glass used by our staff undergoes temper in special furnaces with safeguards on the quality of work performed.