Systemic hazard analysis of offshore service operations

Abstract. As windfarms are moving further offshore, logistical concepts increasingly include service operation vessels (SOV) as the prime means of service delivery. However, given the complexity of SOV operations in hostile environments, their safety management is challenging. The objective of this paper is to bring awareness of hazards that may have been overlooked in earlier assessments, and allow for a preliminary comparison of various operational stages. To this end, we use a systems approach to identify and analyse hazards arising during the SOV transit and manoeuvre within a windfarm and interfaces with turbines and daughter crafts. The hazard analysis is performed by systemic method STPA, allowing to explore hazardous scenarios caused by flawed interactions between system components and, to a lesser extent, by component failures. The results comprise 23 operational hazards arising during the three stages of SOV operation and 1270 hazardous scenarios (pathways) leading to the hazards. The preliminary comparison of SOV operations shows that approaching and departing from turbines in auto and manual modes is potentially the riskiest stage of SOV operation. The lowest risk is of the SOV interface with daughter crafts. The paper discusses the analysis results and explains how they can be used to inform new and existing safety management systems of SOV.