HEAT SOAKING

Glass can contain inclusions of various natures, one of them being Nickel Sulfide (NiS). When glass is heat treated through our tempering process, the possibility of these NiS inclusions causing spontaneous breakage exists. To test for the possibility of NiS inclusions in glass, we utilize the heat soaking process. 

Nickel Sulfide Inclusion

In compliance with the European Standard EN14179 and ASTM requirements, the glass undergoes 3 vitals steps in the heat soaking process.

1. A heating phase: The glass is slowly brought up to the required temperature of 260°C.
2. A soaking phase: We expose the glass to the required temperature with a +/-10° variance for 2 hours.
3. A cooling phase: The glass is slowly cooled back to room temperature. 

In the event that an NiS inclusion is present in the tested glass, the contaminated piece will break during this testing process. With thermocouples and process tracking, we can verify that the glass was held at appropriate temperatures and the heat soaking process is complete. Though the heat soaking process cannot fully eliminate risk of spontaneous breakage, it provides an industry accepted testing process to ensure against NiS induced breakage.