HEAT-STRENGTHENED GLASS
Heat-strengthened glass has been subjected to a heating and cooling cycle and is generally twice as strong as float glass of the same thickness and configuration. Heat-strengthened glass has greater resistance to thermal loads than float glass and, when broken in service, the fragments are larger than those of tempered glass. Heat-strengthened glass is not a safety glass product as defined by European Building Regulations and Standards. This type of glass is intended for general glazing, where additional strength is required to withstand wind load and thermal stress. It does not require the strength of tempered glass, and is intended for applications that do not specifically require a safety glass product. Heat-strengthened glass cannot be cut or drilled after heat strengthening and any alterations, such as edge grinding, sandblasting or acid-etching, will weaken the glass and can cause premature failure.