Risk-Based Approach to the Selection of Fire Exit Strategies for Non-Compliant Buildings

Building law allows the use of a building that is non-compliant with fire safety regulations, provided that enhanced fire exit strategies are implemented to mitigate the negative impact of this non-compliance on fire safety. This article demonstrates the potential of using a probabilistic fire risk analysis method—multisimulation—to increase the efficiency of selecting fire exit strategies. Multisimulation is a quantitative risk analysis method that utilizes, among other things, computer models of fire development and evacuation, as well as modern mathematics and computer science. The main aim of multisimulation is to perform multiple computer simulations (hence the name) for as many fire scenarios as possible in a given building. This article demonstrates the potential of using this method in a practical approach to ensuring fire safety. For this purpose, an existing auditorium building was analyzed, in which numerous non-compliances with applicable regulations were identified. The analysis included 1000 fire and evacuation simulations in a theater auditorium equipped with two emergency exits and 1000 fire and evacuation simulations in a theater auditorium equipped with three emergency exits. In the simulations of both scenarios, the duration of a performance conducted with a full audience and people performing on stage was modelled. The results clearly demonstrated a significant improvement in safety when three emergency exits were available. In terms of both the required safe egress time (RSET) and risk analyses, when three emergency exits were available (instead of the required two), the possibility of having only one functioning exit, which may occur due to a human error, was eliminated. Therefore, it was undoubtedly confirmed that the use of a third emergency exit is justified as an optimal fire exit strategy or a future legislative requirement.