Fire safety provisions and evacuation strategy for supertall residential building in Hong Kong

Abstract

Staircase is the most common and important means of escape in many buildings. A safe and efficient evacuation is a key issue to the fire safety of occupants, especially in a supertall building. Currently, empirical calculation and computational software are widely adopted to examine the total required evacuation time of each building. The maximum movement speed or evacuation flow depends much on the configuration of staircase and the assumptions of human walking speed. As there are more and more concern on the effect of evacuation time due to various human behaviors during the crowd and emergency situation, the actual time required will longer than the value obtained by the simulation. Furthermore, when considering the effect of ageing problem, physical challenge of an elderly travelling long distance will further prolong the evacuation time. As fire cases more commonly happened in residential building, hence, this report reviews the problems of the current evacuation strategy for a supertall residential building in Hong Kong by both empirical calculation and computer simulation. Regarding to the problems found, feasible evacuation strategies – phased evacuation and defense-in-place are proposed to minimize the number of occupants involved in the evacuation, and thus the population density along the evacuation routes. A noticeable reduction of evacuation time is achieved by adopting the new strategy comparing with current strategy. Upon the new strategy, automatic sprinkler system is proposed to be installed in the corridor and staircases of residential building in order to minimize the fire spread and enhance the safety level of occupants which carry out defense-in-place approach in the unaffected part of the building. Based on the findings of this paper, it was highly recommended to develop a more reliable and appropriate evacuation strategy for residential buildings to minimize effect of human behavior on evacuation time and consider the needs of society in the future.