Citation

Gandhi PD. Fire Safety J. 1993; 20(2): 115-133.

Copyright

(Copyright © 1993, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Fires in a room often start small with the ignition of a combustible item such as a waste paper basket. As the fire grows, a smoke layer develops at the ceiling level. The smoke, as it descends, obscures signs and egress routes, thus making it difficult to escape from the fire affected room.In this paper, a brief discussion is given on the measurement of smoke and the importance of various smoke measurement parameters. A model is then developed for predicting smoke obscuration in the fire-affected room, using calorimeter data and concepts of zone modeling. The smoke parameter ([sigma]/hc) is revealed to be an important parameter that governs smoke obscuration for both steady and growing fires.A parametric study is conducted for the steady and t2 growing fires, using the temperature and smoke layer elevation data from the HAZARD I fire model. The study shows that smoke obscuration increases with both the fire size and the [sigma]/hc ratio. However, the hot gas layer density appears to have a significant influence in tempering the increase in obscuration with fire size. In the growing fire case, the obscuration appears to attain an asymptotic value after the initial rapid increase.