Implementation of system-based hazard Analysis on physical safety barrier: A case study in subsea HIPPS

Abstract

Physical safety barriers are provided in industrial systems to prevent/control/mitigate undesired events. However, despite their highly redundant and reliable design, multiple barriers can be penetrated simultaneously as shown by the Deepwater Horizon blowout accident. Their functionality was degraded, not only because of components failures, but also due to management and organizational factors, e.g. inadequate operator training, ineffective maintenance, and poor safety culture. These factors are sourced from management's decisions and actions to prioritize profitability over safety, which covertly generate hazards to the system. However, conventional hazard analyses are unable to identify these hazards. A hazard analysis called System-Theoretic Process Analysis (STPA) is believed to enable the identification of hazards that are rooted from management's unsafe decisions and actions, thus preventing degradation of physical safety barriers in a broader perspective. This paper will discuss the application of STPA for the High-Integrity Pressure Protection System (HIPPS) in subsea production system.