Human reliability analysis of an offshore emergency blowdown system

An offshore platform depressurisation (blowdown) system was designed such that control in emergencies necessitated operator actions over a short space of time. The system design for these operations was analysed using a simple and pragmatic human reliability approach, embedded within a comprehensive risk assessment. The human reliability analysis identified several ways in which human actions could lead to system failure (flare overload), and in the total risk analysis these errors were found to dominate the risk picture. The causes of the human error related primarily to the design of the interface and co-ordination/communication problems previously unaddressed by the design process. Recommendations were made to reduce error potential based on the causes and mechanisms of error identified in the analysis, and several of these recommendations were included in the final design of the system.