The Problem of Sprinkler Reliability

Abstract

Annotation. Sprinkler systems allow a considerable reduction of fire risk in buildings. Unfortunately, sprinklers are not failsafe technical systems. Relatively high rates of sprinkler failures evoke the problem of reliability. A solution to this problem is considered from several viewpoints. The diversity of sprinklers' failure modes is the first challenge for estimating reliability (failure probability). It is found that the use of the available data for estimation is problematic. The second challenge is that the published data is insufficiently described to allow a verification of its relevance to the specific case of failure probability estimation. It is suggested to apply the published data with partial relevance to Bayesian inference about failure probabilities. The data is used for developing prior distributions of the unknown values of the probabilities. Bayesian inference is carried out on the basis of binomial distribution used to model the operation of sprinklers on demand basis. A problem of aging and a possible increase in failure probability in the course of sprinkler service is shortly discussed.

Examining the fire risk in London dwellings using the London Fire Brigade Incident database

“…This means that of the small number of fires in buildings with sprinklers, only 52% of the fires were controlled. This is an unexpectedly low number that requires further investigation, although it is not entirely anomalous due to previous papers detailing the problems with sprinkler reliability, with one such study 36 finding the percentage of sprinkler systems that failed to carry out their function was relatively large. However, it could also be possible that these systems were so effective in controlling the fire in some cases that the fire brigade was never called in the first place.…”

“…This means that of the small number of fires in buildings with sprinklers, only 52% of the fires were controlled. This is an unexpectedly low number that requires further investigation, although it is not entirely anomalous due to previous papers detailing the problems with sprinkler reliability, with one such study 36 finding the percentage of F I G U R E 1 1 Proportion of fires where at least one alarm was present (A, left) and was successfully raised (B, right). The line of best fit is for all types of dwellings combined (for clarity, given that the trend is similar for all dwelling types).…”