Heat soaking is a process that potentially exposes critical nickel sulphide inclusions (NiS) in fully tempered glass. At Garibaldi, our heat soak oven meets all current EU standards EN 14179– 1:2005 (HST) (as of this writing there is still no American standard). 

Process: 

Standard heat soak testing requires more than ten hours of thermal treatment. This includes 1- 6 hours to heat large quantities of glass to 290°C, followed by a temperature plateau at these temperatures for 3—12 hours before cooling down slowly to ambient temperature. This process will cause any glass containing NiS to break in the heat soak chamber, thus reducing the risk of potential field breakage. Glass without detrimental inclusions will retain proper temper properties and will have minimal risks of spontaneous breakage in the field. While heat soaking is not 100% effective, it will reduce the probability of breakage from a standard 8 in 1,000 down to 5 in 1,000 lites.