Heat treated glass involves subjecting the annealed glass to a thermal process to increase its resistance, and to make it safer in case of breakage. The idea behind heat-treating glass is to substantially improve its strength, as well as making it safer in case of breakage.


The process involves heating the glass to its melting temperature and then quickly air cooling it, creating an internal tension in the glass. This treatment modifies certain properties of the glass, notably making it crumble in case of breakage rather than breaking into sharp fragments.  Tempered glass will have about four times the mechanical strength of an annealed glass of the same thickness, which makes it more resistant to thermal stress, as well as wind load and snow.


This method modifies the internal structure of the glass, but in a different way than tempering. In case of breakage, this process will cause the glass to form a breakage pattern that will be held in place by the frame. The mechanical resistance of heat-strengthened is about twice that of annealed glass of the same thickness.


The Heat Soak test is used to identify and minimize glasses subject to spontaneous breakage.

Nickel sulphite inclusions may be present in float glass.  This contaminant is known to cause spontaneous breakage.

The Heat Soak process consists of reheating tempered glass in a different oven, to cause the glass to break in the presence of nickel sulfite.

This process is recommended for tempered glass that is to be installed in difficult to reach places or at high elevations or locations that broken glass could compromise the safety of individuals.


LAURIER wants to ensure the quality and safety of its tempered glass. Therefore, daily quality control tests are ran and results documented.  Our tempered glass always meets the current standards.


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