glass Toughened (or tempered) glass is made from standard Float Glass to create an impact resistant, safety glass. If float glass is broken it will break into very sharp, hazardous pieces of glass. The process of toughening the glass introduces tensions between internal and external surfaces of a glass panel to increase its strength and also to ensure in the case of breakages the glass shatters into small, harmless pieces of glass. The cut glass panels are put into a toughening furnace. Here the glass panels are heated to upward of 600 degrees C and then the surfaces are cooled rapidly with cold air. This produces tensile stresses on the surface of the glass with the warmer internal glass particles. As the top thickness of the glass cools it contracts and forces the corresponding glass elements to contract to introduce stresses into the glass panel and increasing strength. See also Building construction Glass in green buildings Glass museums and galleries Glazing Quadruple glazing Heatable glass Insulated glazing Leadlight Solar thermal collector Stained glass Stained glass – British glass, 1811–1918 References Noel C. Stokes; The Glass and Glazing Handbook; Standards Australia; SAA HB125-1998 External links Glass Association of North America (GANA) – Architectural Glass educational documents and videos National Glass Association (NGA) – History and Types of Glass Welsh School of Architectural Glass, Swansea – UK's leading centre for teaching and research in architectural glass founded in 1946 Paul Scheerbart: Glasarchitektur (Glass architecture, 1914; German) Reflective building components Soil-based building materials Glass Glass architecture Glass production Transparent materials Architectural elements Windows