An experiment and simulation of smoke confinement and exhaust efficiency utilizing a modified Opposite Double-Jet Air Curtain

Abstract

Fires in high-rise buildings often result in tremendous property losses and heavy casualties. Smoke has been reported to be the main cause of these casualties. A modified Opposite Double-Jet Air Curtain (ODAC) is introduced in order to confine smoke movement and to exhaust smoke during a high-rise building fire. Here, a study including an experiment and a numerical simulation, was performed to determine the efficacy of a modified ODAC. The experiment was conducted on a 1:12 scale model of a high-rise building. A complementary Fire Dynamics Simulator (FDS) simulation was conducted on a full scale building. The influences of the air curtain discharge velocity and heat release rates (HRRs) were examined.The results of this study show that given the same supply air volume and HRR, the carbon monoxide (CO) concentration with the ODAC is clearly lower than the levels found with a traditional air curtain in a high rise building fire. The gas temperatures in the hallway increased significantly with the increase of HRR, and when the HRR reached 1.5MW or more, a significant increase in the temperature of the smoke in the stairwell entrance was observed. When HRR reaches 2MW, and the velocity has increased to 9m/s, the CO concentration in the entrance of stairwell just meets the minimum Safety and Health standards.