Tempered glass
Description
A high strength Plate glass that has been reheated and held above its annealing point (650C or 1200F), then flash cooled. The tempering process makes the glass 3-5 times stronger than ordinary plate glass of the same thickness (Konrad, 1995). However, it cannot be cut or ground. Tempered glass was first used in 1942. On impact, tempered glass shatters into small, granular pieces with round-edges. It is used for large doors and windows, display cases, tables, shelves, aquariums, refrigerator trays, cookware, and mobile screen protectors. Automobile windows are made of tempered glass with the windshields have an additional laminated layer to provide containment of the particles when shattered.
Synonyms and Related Terms
vidrio templado (Esp.); verre trempé (Fr.); gehard glas (Ned.); vidro recozido (Port.); vidro temperado (Port.); heat-strengthened glass; hardened glass; toughened glass; safety glass; Tuf-Flex [Libbey-Owens-Ford]; Herculite [PPG]
Environmental Risks
Tempered glass is not recyclable.
Physical and Chemical Properties
The glass has tensile stresses within the body that are balances by compressive stresses on the surface. When viewed through a polarizing filter, tempered glass shows variations in stress
Resources and Citations
- Wikipedia: Tempered glass Accessed Oct. 2023
- K.Konrad, K. Wilson, W. Nugent, F.Calabrese, "Plate Glass", in Twentieth-Century Building Materials, T. Jester (ed.), McGraw-Hill: New York, 1995.
- Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
- Thomas C. Jester (ed.), Twentieth-Century Building Materials, McGraw-Hill Companies, Washington DC, 1995
- Encyclopedia Britannica, http://www.britannica.com Comment: "industrial glass." Accessed 2 Dec. 2004.