BS EN 61511-3:2017

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms, definitions and abbreviations
Annex A (informative) - Risk and safety
        integrity - general guidance
Annex B (informative) - Semi-quantitative
        method - event tree analysis
Annex C (informative) - The safety layer
        matrix method
Annex D (informative) - A semi-qualitative method:
        calibrated risk graph
Annex E (informative) - A qualitative method:
        risk graph
Annex F (informative) - Layer of protection
        analysis (LOPA)
Annex G (informative) - Layer of protection analysis
        using a risk matrix
Annex H (informative) - A qualitative approach for
        risk estimation & safety integrity level
        (SIL) assignment
Annex I (informative) - Designing & calibrating a
        risk graph
Annex J (informative) - Multiple safety systems
Annex K (informative) - As low as reasonably
        practicable (ALARP) and tolerable risk
        concepts
Bibliography
Annex ZA (normative) - Normative references to
         international publications with their
         corresponding European publications

Gives information on: - the underlying concepts of risk and the relationship of risk to safety integrity; - the determination of tolerable risk; - a number of different methods that enable the safety integrity level (SIL) for the safety instrumented functions (SIF) to be determined; - the impact of multiple safety systems on calculations determining the ability to achieve the desired risk reduction.

IEC 61511-3:2016 is available as IEC 61511-3:2016 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.



IEC 61511-3:2016 applies when functional safety is achieved using one or more SIF for the protection of either personnel, the general public, or the environment; may be applied in non-safety applications such as asset protection; illustrates typical hazard and risk assessment methods that may be carried out to define the safety functional requirements and SIL of each SIF; illustrates techniques/measures available for determining the required SIL; provides a framework for establishing SIL but does not specify the SIL required for specific applications; does not give examples of determining the requirements for other methods of risk reduction. This second edition cancels and replaces the first edition published in 2003. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: Additional H&RA example(s) and quantitative analysis consideration annexes are provided.