One-Way Coupling of Fire and Egress Modeling for Realistic Evaluation of Evacuation Process

He-In Cheong,Arnab Majumdar,Washington Yotto Ochieng,Zhiyu Wu

doi:10.1177/03611981211032636

Abstract

In the discipline of fire engineering, computational simulation tools are used to evaluate the available safe egress time (ASET) and required safe egress time (RSET) of a building fire. ASET and RSET are often analyzed separately, using computational fluid dynamics (CFD) and crowd dynamics, respectively. Although there are advantages to coupling the ASET and RSET analysis to quantify tenability conditions and reevaluate evacuation time within a building, the coupling process is computationally complex, requiring multiple steps. The coupling setup can be time-consuming, particularly when the results are limited to the modeled scenario. In addition, the procedure is not uniform throughout the industry. This paper presents the successful one-way coupling of CFD and crowd dynamics modeling through a new simplified methodology that captures the impact of fractional effective dose (FED) and reduced visibility from smoke on the individual evacuee’s movement and the human interaction. The simulation tools used were Fire Dynamics Simulator (FDS) and Oasys MassMotion for crowd dynamics. The coupling was carried out with the help of the software development kit of Oasys MassMotion in two different example geometries: an open-plan room and a floor with six rooms and a corridor. The results presented in this paper show that, when comparing an uncoupled and a coupled simulation, the effects of the smoke lead to different crowd density profiles, particularly closer to the exit, which elongates the overall evacuation time. This coupling method can be applied to any geometry because of its flexible and modular framework.

Highlights

In the discipline of fire engineering, computational simulation tools are used to evaluate the available safe egress time (ASET) and required safe egress time (RSET) of a building fire
A fire evacuation is typically categorized into substages of required safe egress time (RSET), that is, the time needed by occupants to evacuate from the fire to a safe place from the point of the fire ignition
RSET and ASET are closely linked, evacuation simulations are often conducted independently from the fire modeling process for a variety of reasons, apart from fire and evacuation modeling belonging to different disciplines

Summary

Introduction

In the discipline of fire engineering, computational simulation tools are used to evaluate the available safe egress time (ASET) and required safe egress time (RSET) of a building fire. The results presented in this paper show that, when comparing an uncoupled and a coupled simulation, the effects of the smoke lead to different crowd density profiles, closer to the exit, which elongates the overall evacuation time. This coupling method can be applied to any geometry because of its flexible and modular framework. Fire evacuation simulation serves different purposes, one being the prediction of a possible evacuation scenario and another being post-incident evaluation For the former, as it is time-consuming to model every likely fire evacuation scenario, the coupling of fire and evacuation modeling is an uncommon practice for building design. For postincident evaluation, using a coupled model would serve as a powerful tool in understanding how a fire evacuation may have taken place

Results

Discussion

Conclusion