Process safety, instrumented safety barriers — what can we learn from the nuclear industry?

Both in the Oil & Gas industry and in the Chemical Process industry there is a high focus on process safety and on reliability of instrumented safety systems. New international standards like IEC 61508 have been pushing the formalization and documentation of the reliability of such systems. In this context, it is of interest to investigate what can be learnt from other technically advanced industries with high safety requirements, and how we can benefit from transfer of practices, experiences and methods for analyzing barrier reliability and dependencies between "independent" barrier levels. The paper gives an outline of how instrumented safety systems and barriers in a nuclear power plant are established, analysed, and maintained. Monitoring of the status and reliability of safety systems can be done on a day by day basis during the operational phase. Practical examples from the nuclear industry are included, as well as illustrations on how experience from some of these principles may be applied in the oil and gas industry.