Numerical Study on the Definition of the Exhaust Effectiveness of Smoke under Fire in a Large Space

Abstract This paper investigates the exhaust effectiveness of smoke, in the case of fire in a large atrium space. Numericalanalysis was conducted to simulate transient fire growth in a test room, modeled by the Murcia atrium fire test. Various indices representing the exhaust performance of the exhaust system were obtained, such as the height of the smoke layer, and the instantaneous and accumulative capture efficiency of the smoke. The residual life time of smoke from the fire wasalso obtained, by injecting tracer gases at the fire location, depending on the airflow rate, and the location of the exhausts. The capture efficiency based on smoke concentration at the exhausts exhibits how much smoke can be removed by theexhaust system; whereas, the exhaust effectiveness based on residual life time indicates how rapidly the smoke can reachthe exhaust locations, before being exhausted. The definitions and meanings of the indices to be used in representing theexhaust performance of a smoke exhaust system installed in a large space are discussed.

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