1. ANSI/ISA—84.00.01—2004 Part 1 (IEC 61511-1 Mod), Functional safety: safety instrumented systems for the process industry sector — Part 1: Framework, definitions, system, hardware and software requirements.
2. ANSI/ISA—84.00.01—2004 Part 2 (IEC 61511-2 Mod) , Functional safety: safety instrumented systems for the process industry sector — Part 2: Guidelines for the application of ANSI/ISA—84.00.01—2004 Part 1 (IEC 61511-1 Mod).
3. ANSI/ISA—84.00.01—2004 Part 3 (IEC 61511-3 Mod) , Functional safety: safety instrumented systems for the process industry sector — Part 3: Guidance for the determination of the required safety integrity levels — informative.
4. Using risk tolerance criteria to determine safety integrity levels for safety instrumented functions;Baybutt;J. Loss Prev. Process Industries,2012
5. Risk tolerance criteria for layers of protection analysis;Baybutt;Process Saf. Prog.,2012