UNE-EN 61511-3:2006 Functional safety - Safety instrumented systems for the process industry sector -- Part 3: Guidance for the determination of the required safety integrity levels
2017UNE-EN 61511-3:2017 Functional safety - Safety instrumented systems for the process industry sector - Part 3: Guidance for the determination of the required safety integrity levels (Endorsed by Asociación Española de Normalización in June of 2017.)
2006UNE-EN 61511-3:2006 Functional safety - Safety instrumented systems for the process industry sector -- Part 3: Guidance for the determination of the required safety integrity levels