Citation

Marshall NR. Fire Safety J. 1985; 9(3): 245-255.

Copyright

(Copyright © 1985, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper describes a detailed study of the movement of smoke in staircases using a one-fifth scale model of a five-storey staircase.The flow processes observed within the staircase were complex. The height (xs) of the nominal smoke base above the fire compartment (i.e., the height of the equivalent ideal smoke layer having the same static buoyant head as the gases in the stairwell) was found to be proportional to the fourth power of the ratio of the mass flow of air entrained within the stairwell () to the mass flow of gases leaving the fire compartment () where [alpha] = 4.9 x 10-3 +/- 3 x 10-4.This equation can be solved simultaneously with an equation describing venting in the stairwell (also given in the paper) to give (), and hence the dilution of smoke within the staircase, and also the mass flow (and change in smoke concentration) of gases leaving the staircase, perhaps into an upper floor.These equations are suitable for incorporation into existing computer programs for predicting movement of smoke and fire gases, with the aim of increasing their usefulness as design aids for life safety in buildings.