Safety of Heat Soaked Thermally Toughened Glass: How Exactly Must the Standard Conditions of the Heat Soak Process be Complied With?

Andreas Kasper

In prEN 14179-1 "Heat soaked thermally toughened soda lime silicate safety glass - Part 1: Definition and description" developed by CEN/TC129, and published in 11/2000, a heat soaking procedure is prescribed to prevent toughened building glasses from spontaneous failure caused by nickel sulfide inclusions. Its spirit is that the glass temperature has to be kept at (290±10)°C during two hours. After this heat soaking, all kinds of glass sheets, independently from their size and thickness, are assumed to be sufficiently safe on the building. But what happens if the prescribed conditions are not met? Influences of heating rate, and temperature and time variations during the holding period are described and calculated. Also the influence of the differences in size of the glass panels and their tempering degree are discussed.

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The Authors

Dr. Andreas Kasper Dr. Saint-Gobain Profession: ChemistOccupation: Head of project group "chemistry of glass melting"Responsibilities:Chemical analysis of glass and raw materials; environmental measurements (emissions of glass tanks); s... Read more