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Accounting for Emergency Response in Building Evacuation: Modeling Differential Egress Capacity Solutions



Jason D. Averill, Weiguo Song


The impact of firefighter response on the progress of the building evacuation is not typically considered. The emergency response can significantly increase total building evacuation time. In order to account for emergency response, this analysis considered whether adding capacity through extra stairwell width was equivalent to providing the same total egress capacity through an extra stairwell. An egress simulation with a counterflow submodel was validated against recent fire-drill experimental results to demonstrate the capability of the model to produce meaningful evacuation results. The model was then applied to a hypothetical 50 story office building with 350 occupants per floor. When comparing equivalent total width, additional stairwells outperform wider stairwells from the perspective of evacuation performance, as well as firefighter ascent times. A third stairwell can completely mitigate the effect of firefighter response or even improve the building evacuation time compared to two stairwells with no firefighter response.
NIST Interagency/Internal Report (NISTIR) - 7425
Report Number


Averill, J. and Song, W. (2007), Accounting for Emergency Response in Building Evacuation: Modeling Differential Egress Capacity Solutions, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed July 24, 2024)


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Created April 1, 2007, Updated August 3, 2009