Cause-consequence analysis (CCA) combines the inductive and deductive reasoning of logic diagrams (e.g., event-tree analysis (ETA) or fault-tree analysis (FTA)) to identify the basic causes and consequences of potential accidents. Bowtie diagramming, a less formal CCA than ETAs and FTAs, provides a pictorial representation of the risk assessment process, and during the last decade, the use of bowtie diagrams has become increasingly popular, especially in the exploration and production, oil and gas sector. Because of their unparalleled advantages demonstrating that major hazards are identified and controlled, bowties are widely used in Europe to support safety reports and HSE cases for drilling and grassroots onshore projects. Other applications have been reported for healthcare, nuclear, transport, and organizational culture.
This paper discusses the evolution of the risk-based approach in the United States and how the bowtie model would fit in the risk management process, and it shares representative bowtie case study applications in making engineering controls operational for a diverse range of oil and gas facilities.