Compliance with the harmonized European Norms (hENs) on the durability of thermally treated safety glass is inexorably linked to the process of the Heat Soak Test, performed through a tempering heat soak test furnace. Through this process, tempered glass becomes certified against spontaneous breakage.

During the process of fabrication of a sheet of float glass, an undetectable inclusion of traces of nickel sulfide (NiS) can be trapped within the mass of the glass.

This constitutes an “Achilles’ heel” for the otherwise highly safe tempered glass, as the nickel sulfide tends to expand and contract within the glass during potentially wide temperature fluctuations that a glass installation can experience over time. This in turn can lead the spontaneous breakage of tempered safety glass, without forewarning and at any time during the lifetime of the glass installation.

In order to minimize that risk, tempered glass needs to be subjected to a Heat Soak Test, a process under which the glass is, among other parameters, subjected to a temperature of 290oC for a given time period which varies proportionally to the load of the furnace.

VASGLASS offers to architects and construction professionals the option to apply this innovative and important treatment to any tempered glass application, accompanied by the certificate of compliance to the relevant European Norm.