Citation

Morgan HP, Hansell GO. Fire Safety J. 1985; 8(3): 187-198.

Copyright

(Copyright © 1985, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

There is a trend for many new office buildings to include a smoke ventilation system. This is especially true of 'Atrium' buildings. At present there are no clear grounds for choosing a fire size on which to base the design of such ventilation systems.This paper draws on the U.K. Fire Statistics Data Base for 1978 and 1979 establish the proportion of reported fires exceeding any given size (the relative frequency), for both sprinklered and unsprinklered offices. Given a decision about a reasonable proportion of fires growing larger than a particular area, the paper shows how this area can be used to determine whether the fire will be ventilation or fuel-bed controlled. It further shows how the heat carried by the gases leaving the office (e.g., into an atrium) can be estimated by the ventilation system's designer, for either ventilation or fuel-bed controlled fires, whether sprinklered or not.For example, if a relative frequency of 10% is deemed reasonable the design fire area is 16 m2 sprinklered or 47 m2 unsprinklered. The design heat output will vary between 0.3 MW and 4.5 MW depending on the building's circumstances.The study suggests that fitting sprinklers in open plan offices may give a major advantage in reducing the capacity required of a smoke ventilation system, but much less of an advantage for cellular offices.It is also suggested that the British Standard for means of escape from offices is generally successful in preventing casualties.