THE EFFECT OF STAIR WIDTH ON OCCUPANT SPEED AND FLOW OF HIGH RISE BUILDINGS

Abstract

This research investigates the influence of stairwell width on velocity and specific flow of occupants descending stairs during building evacuations. It examines data collected by the National Institute of Standards and Technology taken from eight different stairwells during unannounced fire drills in four buildings. Based on the raw data given by NIST the velocity, density, and specific flow were calculated for each occupant on every floor in which data was collected. Though data was noisy, results demonstrate that there is a linear trend between density of occupants in a stairwell and the velocity they descend at. There is also a parabolic trend between density and specific flow rate of occupants on stairs. While no direct correlation was found, stairwell width does seem to influence the speed and specific flow of occupants since the stairwell with the smallest effective width found occupants traveling slower. As well, the correlations in the SFPE Handbook, developed by Nelson and Mowrer concerning velocity and specific flow rate, were found to be an upper limit on the data that was analyzed.