How does the Heat Soak Test (HST) work with toughened glass?
Understanding the mechanism of spontaneous nickel sulfide failures helped develop a method to eliminate panes likely to suffer breakage: Heat Soak Test, or HST. Toughened glass is heated up to approximately 290oC for a period of time specified in the applicable standard. Close to 99% glass panes with inclusions will be identified and suffer fracture. Why should you ask for HST toughened glass? There is a growing tendency to require glass used for large projects be HST tested. Regulations become more stringent and investors better aware of potential consequences caused by spontaneous fractures of already installed glazing systems. Fractured glass panes must be promptly replaced, a very costly procedure often calling for a lifting crane or other specialized equipment. A broken pane may leave facilities with restricted access wide open. Fracture of a tempered faade pane occurring at a high elevation may cause injuries when glass shards, despite their small size and blunt edges, hit people
