Fire Safety Science Digital Archive

The spread of fire in buildings is studied in this paper by examining the statistics of fires attended by the brigades. It is suggested that since traditional methods of specifying fire resistance based on a 'burn-out' tacitly recognize some element of risk, one should find some means of making an appropriate allowance quantitatively, including the beneficial action of fire fighting, sprinklers etc. One way is to evaluate the probability of spread beyond the room of origin, which is shown to be a useful measure of the incidence of large fires, and hence to evaluate the influence of various factors on the spread of fire. Only limited analysis is possible because of few data, but it is shown that spread is much less likely in modern buildings, that the effect on it of early attendance by the brigade is small, but that early discovery is very important. It is also shown that small reductions in the frequency with which fires spread beyond the room of origin can result in relatively large reductions in the incidence of large fires, a result of considerable economic significance, and strong statistical evidence of the value of compartmentation.