This pack contains the following: IEC 61511-1:2016 RLV IEC 61511-2:2016 RLV IEC 61511-3:2016 RLV IEC 61511-1:2016 gives requirements for the specification, design, installation, operation and maintenance of a safety instrumented system (SIS), so that it can be confidently entrusted to achieve or maintain a safe state of the process. IEC 61511-1 has been developed as a process sector implementation of IEC 61508:2010. IEC 61511-2:2016 provides guidance on the specification, design, installation, operation and maintenance of SIFs and related SIS as defined in IEC 61511-1:2016. IEC 61511-3:2016 provides information on: the underlying concepts of risk and the relationship of risk to safety integrity (see Clause A.4); the determination of tolerable risk (see Annex K); a number of different methods that enable the safety integrity level (SIL) for the safety instrumented functions (SIF) to be determined (see Annexes B through K); the impact of multiple safety systems on calculations determining the ability to achieve the desired risk reduction (see Annex J).