ABSTRACT
Intended function refers to the correct/proper design following a sprinkler standard. Data on a residential system expected to prevent flashover are treated in the same way as an ESFR system that provides fire suppression; this shows the need to understand reliability for different sprinkler types. Their performance is not the same; therefore, their reliability is not the same. Operational reliability/operationality/operability is a measure of the probability that a protection system or part of it will operate when needed. Performance reliability or efficiency is a measure of the adequacy of the system to successfully perform its intended function under specific fire scenario conditions. What factors contribute to the perception of what reliability is and what factors belong to system reliability? Interestingly, even if uncertainty is a common part of life, this is seldom mentioned in the literature on reliability.
