Experimental Study on Thermal Breakage of Four-Point Fixed Glass Façade

As the weakest part of building façades, glass panels can easily break in fires and change the compartment fire dynamics by creating new openings for air to enter.A series of full scale tests were conducted to investigate the thermal breakage and fallout of four-point fixed glass façades, in which glass panes of 1200 × 1200 × 6 (mm 3 ) were placed at 35, 45, 50 and 70 (cm) away from n-heptane pool fires on a 500 × 500 (mm 2 ) square pan.Both float and toughened glasses were investigated.The glass surface temperature, gas temperature at the centre of the exposed side and heat release rate were measured and analyzed.The cracking patterns and glass fallout processes were recorded by digital camera.It is found that all the cracks initiated from the fixed point and their intersections formed islands to cause glass pieces fallout when the exposed side reached around 200-300 °C for the float glasses tested.The fallout fractions suggest that once the first crack is initiated, the point-supported glass panes are much more easily to fallout than edge covered glasses.The toughened glass panes were found to be softened by the fire and bent, but they did not crack even when the fire directly impinged on them.KEYWORDS：Glass façade, thermal breakage, safe distance, fire resistance