A simplified procedure for the analysis of Safety Instrumented Systems in the process industry application

The aim of this paper is to propose a simplified and more efficient methodology for safety assessment of electromechanical SIS in compliance with the Standards IEC 61508 and IEC 61511. The proposed technique is based on an alternative implementation of the Reliability Block Diagram (RBD) approach for the performance analysis of the Safety Instrumented System. In order to demonstrate the advantages of the proposal, a case study of some of the safety functions is considered. With respect to other methodologies normally used for safety analysis, the results proved the proposed approach both easier in the application and time-saving. In addition, such results are comparatively close to those obtained by using the Standard methods.