1 Copyright © ### # by ASME INTEGRATED BARRIER ANALYSIS – A METHODOLOGY TO REVEAL WEAKNESSES IN OFFSHORE PETROLEUM OPERATIONS

The regulations from the Petroleum Safety Authority Norway (PSA) for the management of health, safety and environment of offshore petroleum installations call for a dedicated assessment and evaluation of all barriers against major hazards, both physical and non-physical, as well as any interdependencies and common threats to barriers and barrier elements. Such assessments and evaluations have not been carried out for offshore installations, although corresponding requirements apply in other industries, most notably in the nuclear power industry. A comprehensive R&D program initiated by the Norwegian Research Council has set a goal to carry out an extensive demonstration project, whereby all relevant barrier elements are integrated into one comprehensive model, for a dedicated case study. A method has been proposed based on use of Fault Trees, Event Trees, Influence Diagrams, Risk Influencing Factors and simplified analysis of dependencies between RIFs. The method was outlined in a PSAM7 paper in 2004. Some case studies in order to demonstrate application of the method and explore the strengths and challenges of the analysis have been carried out in 2004 and 2005. The case studies have focused in particular on the robustness of the results, and the usefulness of quantitative results in a risk-informed decision-making context in the operations phase of an offshore petroleum installation. The case studies have been quite different with respect to input dat