Experimental investigation on thermal performance of water wall systems exposed to fire

Water wall systems (WWSs) are increasingly being used as glass façades in modern green buildings owing to their enhancement in building energy efficiency. However, little is known about their performance when exposed to fire. In this study, 500 × 1000 mm2 sized water wall systems with 30 mm, 50 mm and 100 mm thick water columns were tested and compared to the thermal performance of a 500 × 1000 mm2 sized single skin glass façade system. These façade systems were heated by a 400 × 600 mm2 isopropanol pool fire. The distance from the pan centre to pane 1 of the façade was 350 mm. Time to first crack and surface temperatures were measured. The experimental results indicate that single skin glass façades are more vulnerable to cracking than water wall systems, but exposed glass pane fallout can easily occur in water wall systems compared to single skin façades. Since the overall performance is dependent on the failure of the fire unexposed glass pane, water wall systems are more fire resistant than single skin glass façades. The water layer thickness significantly affects the WWS thermal performance, where a 50 mm thick water layer would result in a longer time to first crack. The experimental findings of this study are useful for developing practical guidelines for fire-safe glass façade designs.