ISA 61511-3 PDF

Functional Safety – Safety Instrumented Systems for the Process Industry Sector – Part 3: Guidance for the determination of the required safety integrity levels (IEC 61511-3:2016, IDT)

ISA 61511-3 – Functional Safety – Safety Instrumented Systems for the Process Industry Sector – Part 3: Guidance for the determination of the required safety integrity levels (IEC 61511-3:2016, IDT)

ISA 61511-3-2018 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).

In particular, this part of IEC 61511:

• 1.applies when functional safety is achieved using one or more SIF for the protection of either personnel, the general public, or the environment;
• 2.may be applied in non-safety applications such as asset protection;
• 3.illustrates typical hazard and risk assessment methods that may be carried out to define the safety functional requirements and SIL of each SIF;
• 4.illustrates techniques/measures available for determining the required SIL;
• 5.provides a framework for establishing SIL but does not specify the SIL required for specific applications;
• 6.does not give examples of determining the requirements for other methods of risk reduction.