Advances In Testing Tempered Glasses In Heat Soak Ovens

Spontaneous fracture of tempered glass due to NiS inclusions is well known and described in literature since 1961. In previous reports it has been noted that the so-called "Heat Soak Test" (HST), which avoids spontaneous fracture of glass sheets on buildings, has still the potential to be optimised further. Increased realiability is possible even with shorter test times. This paper continues the work by new kinetic results and there-on based calculations. The evaluation of real HST breakage time dependence of two different HST oven types will prove that optimising the test is really possible by controlling the heating and holding phases of the HST.