Anatomy of surge analysis for industrial firewater systems - 'we never have problems with firewater systems!'

摘要

When confronted by a recommendation for a surge analysis of a firewater system, Fire Protection and Process Safety Engineers' first response is often "we haven't done that before, why do we have to do it now?" Firewater systems for industrial plants, airports and process systems are significantly larger than in the past, and (happily) there is relatively little experience with system performance under design conditions. We present a case in which the analysis of the sudden activation of firewater monitors predicted a piping failure which was subsequently (and unintentionally) confirmed by field testing together with some issues with a major addition to the existing system. We hope with this paper to provide some guidance through the labyrinth of codes and often conflicting requirements that must be traversed in order to achieve a robust design. Problems are reviewed with respect to discerning what design codes may apply and establishing permissible transient pressures for hydrants, monitors and valves for which manufacturers offer no surge-related criteria.