ABSTRACT
An evacuating wheelchair party was introduced into the flow of evacuees in an escape stairway and its effect on the behavior of the evacuees was observed. This chapter analyses this unannounced evacuation, the effect of the introduction of the wheelchair party into the flow of evacuees, the descent speed of the wheelchair party, and raises questions regarding the efficacy of evacuation drills. The unannounced evacuation was conducted on the morning of May 4, 1995. The mean travel speed of the wheelchair party in the intermediate landings was 0.39 m/s and ranged between 0.36 m/s and 0.41 m/s. The relationship between speed and density obtained in this uncontrolled unannounced evacuation for evacuees ahead of and behind the wheelchair party. The travel speed of the wheelchair party on the stair in this uncontrolled unannounced evacuation is much slower. The travel speed and flow of evacuees ahead of the wheelchair party were much greater than that for the evacuees following the wheelchair party.
