Thermal Breakage of Tempered Glass Façade with Down-Flowing Water Film Under Different Heating Rates

The objective of this work is to investigate the effect of the heating rate on the thermal breakage and fallout behavior of the tempered glass with down-flowing water film. The heating rate of the glass panes was controlled by changing the distance between the fire source and the glazing surface, which ranged from 0.6°C s−1 to 1.0°C s−1. N-heptane pool fire was adopted to heat up the glass panes and the fuel pan was positioned 500 or 600 mm away from the exposed glass surface. During the experiments the water film was initiated manually when the maximum glazing temperature reached different designed values. The results show that all the glazing panes kept their integrity when the fire source distance was 500 mm. In contrast, all the glass panes cracked and fell out the frame when the fire source distance was 600 mm except the one with the water film discharged at 200°C. The results illustrate that the heating rate plays a key role on the breakage of glass façades. Under the effect of water film or sprinkler system, glass panes are more likely to fail when exposed to a fire with smaller heat release rate or greater distance, rather than the opposite case.