Towards the Optimization of the Safety Life-Cycle for Safety Instrumented Systems

The design and development of Safety Instrumented Systems (SIS) according to the IEC 61511 standard is a long and costly process. Although the standard gives recommendations and guidelines for each phase of the safety life-cycle, implementing them is not a simple task. Access to reliability data, hardware and systematic safety integrity analysis, software verification, generation of reports, guarantee of traceability between all the phases and management of the project are some of the main challenges. In addition, some of the industrial processes or test-benches of large scientific installations are in continuous evolution and changes are very common. This adds extra complexity to the management of these projects. This paper presents an analysis of the safety life-cycle workflow and discusses the biggest challenges based on our experience at CERN. It also establishes the basis for a selection of the tools for some of the safety life-cycle phases, proposes report templates and management procedures and, finally, describes the roles of the different members in our functional safety projects.