Probabilistic Risk Assessment Associated with Fire Spread in Segregated Structures

Abstract

A segregated structure is regarded as a collection of volumes joined together by barriers. A fire, starting in one of the volumes, may spread through its bounding barriers to other volumes. The safety assessment of a vital piece of equipment contained in a particular volume, or passing through several volumes, needs to contain a contribution associated with the risk of damage by fire which starts in or spreads to these crucial volumes. A technique is described for doing this using the directed graph of a reduced network with ‘fire transition’ probabilities assigned to its arcs. This time-independent approach has been implemented in a computer program. Examples illustrating its use are given. Extensions which include the temporal aspect, and involve the stochastic modelling of the time taken for a fire to breach a barrier, are discussed.