Atrium smoke filling process in shopping malls of Hong Kong

The smoke filling process in the atria of shopping malls in Hong Kong is studied. The atrium is located adjacent to a shop which is assumed to have a fire. Atria classified into seven different shapes with volumes varying from 2,500 to 35,000 m3 were considered. The smoke filling time in those atria was simulated by the fire zone model CFAST Version 2.0. A total number of 63 atria were considered with the probable fire environment simulated. A time constant derived from the free plume expressions is proposed to specify the geometry of the atrium hall for studying the smoke filling process. It is found that the times required to fill 80% and 50% of the atrium space volume with smoke are related to this time constant. Linear relations between them were derived. Lastly, the effects of the smoke control systems are also studied: the horizontal ceiling vents of area 9 m2 and mechanical ventilation system giving a smoke extraction rate of 6 air changes per hour.