Custom Tempered Safety Glass Tempar-Glas®- For over 60 years, Virginia Glass Products Corporation has been a leading manufacturer of precision custom tempered glass, all glass entrances and doors, and laminated glass for commercial construction and original equipment manufacturing. Tempar-Glas® is the registered trade-name for tempered safety glass manufactured by Virginia Glass Products Corporation.
Tempering Process - Glass is uniformly heated in an oscillating, horizontal, roller-hearth furnace until the entire thickness of the glass has reached a temperature of approximately 1200° F. This can range from between less than 6 minutes for 1/4” glass up to 15 minutes for ¾” glass. Following heating the glass is rapidly cooled, or quenched, by a blast of air uniformly delivered to the top and bottom surfaces of the glass. Immediately upon quenching the surface cools and becomes rigid. The interior, meanwhile, cools at a slower rate and is prevented from contracting by the surface which has already become rigid. Thus, the core is permanently placed in tension, causing compressive forces on the surfaces and edges. This incredible residual compression (in excess of 10,000 psi on the surface) must be overcome before the glass will break. It is this state of surface compression that gives tempered glass its strength as well as its safety characteristics if broken.