Thermal breakage and fallout behaviors of non-tempered glass under the effect of water film

Abstract

Delayed activation of the sprinkler or water film system may accelerate the crack and fallout process of the heated glass when encountered in a fire. A series of tests were conducted to investigate the thermal breakage and fallout behavior of a non-tempered glass façade with down-flowing water films. The most widely used non-tempered glass, low emissivity coated glass (Low-E), and float glass were studied in this work. An n-heptane pool fire was employed to heat up the glass panes and the water film was acted when the maximum glazing temperature reached the different designed values. The results illustrate that water film has little influence on the fracture behavior of float glass. However, the water film does accelerate the crack and fallout process of Low-E glass significantly when the glazing temperature is over 70°C. This is because large thermal stress is generated inside the glass due to the continuous cooling of the cold water film, which exceeds the ultimate tensile stress of glass. The water film also has a large impact on the crack propagation and fallout ratio of the glass panes.