The International Electrotechnical Commission (IEC). First edition. 2003-
03. The International Standard IEC 61511-3 has the status of a British Standard. 56p. This part of IEC 61511 provides information on
– the underlying concepts of risk, the relationship of risk to safety integrity, see Clause 3;
– the determination of tolerable risk, see Annex A;
– a number of different methods that enable the safety integrity levels for the safety instrumented functions to be determined, see Annexes B, C, D, E, and F.