Citation

Graat E, Midden C, Bockholts P. Safety Sci. 1999; 31(2): 127-141.

Copyright

(Copyright © 1999, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper is concerned with the concept of building evacuation and the factors that affect the emergency egress time. It argues that the total evacuation time can be divided into three components: the time to recognize a dangerous situation, the time to decide for evacuation and the time for the movement towards safety. The last component, the egress time, is studied closely in this paper. When the capacity of a walkway is known, this component can be calculated. The capacity however is affected by a number of factors. Through two field studies the effects of the motivation of people to move and the slope of stairs on capacity have been tested. It appears that initially motivation has an accelerating effect, but as the number of people per square meter grows their speed decreases. Also the steeper the slope of stairs, the slower people will move on them. Furthermore the value for capacity used in design and egress time calculations is looked upon. Various researchers have come up with different values. Some recommend the use of the maximum value, which gives the minimum egress time, while others recommend the use of a mean value for capacity, which gives a mean value for egress time. This paper discusses the advantages of the use of a mean value over the use of a maximum value, and thus of the use of an average over a minimum egress time.