Tempered Glass is four to five times mechanically stronger than annealed glass of the same type and thickness. This is due to stresses in the surface layer. Compressive surface stresses close microscopic cracks and make the glass much stronger.
High Thermal - Shock Strength
Tempered Glass is approximately three times as resistant to rapid temperature changes (thermal shocks) as annealed glass. Annealed glass is a brittle material. It breaks under the lowest tensile stress. Tensile Stresses on the surface can be caused by bending the glass sheet or by changes in temperature. A sudden change in temperature of about 40ºC - 50ºC is enough to break annealed glass. Tempered glass can withstand temperature changes of 150ºC without breaking. This is extremely important for architectural glass used in facades, especially in the spandrel areas.
When ordinary annealed glass is broken, it forms sharp, knife-like fragments. DURAGLAS tempered glass however, breaks into small, comparatively harmless pieces, unlikely to cause serious injuries. Its break pattern enables tempered glass to be classified as safety glass.
Tempered Glass can withstand temperatures of up to 295ºC.