Citation

Morgan HP, Hansell GO. Fire Safety J. 1987; 12(1): 9-35.

Copyright

(Copyright © 1987, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper presents methods for predicting, to an accuracy sufficient for smoke-control design purposes, smoky gas flows leaving a compartment on fire and passing into an atrium. It discusses the height of any flames that might be present in the atrium, as well as the temperatures in those flames to which building (or other) materials might be exposed. It presents methods for calculating entrainment into the thermal plume (rising against the wall or out in the open). Much of this is also applicable to the exterior of buildings in the absence of wind.It further presents methods for calculating the time for smoke to fill an atrium to close above the fire, both with and without the presence of venting. It gives formulae for calculating the required capacity of either powered or natural extract for steady-state 'throughflow' smoke ventilation.It is concluded that, apart from exceptional circumstances, it is not usually feasible to design successful smoke-ventilation systems to keep the base of the atrium's buoyant layer more than 8 - 16 m above the fire-room opening. In practice, this means that 'throughflows' smoke ventilation will rarely allow escape routes to be open to the atrium above the fourth or fifth floor.