NBN EN 61511-3 : 2005

INTRODUCTION
1 Scope
2 Terms, definitions and abbreviations
3 Risk and safety integrity - general guidance
  3.1 General
  3.2 Necessary risk reduction
  3.3 Role of safety instrumented systems
  3.4 Safety integrity
  3.5 Risk and safety integrity
  3.6 Allocation of safety requirements
  3.7 Safety integrity levels
  3.8 Selection of the method for determining the required
      safety integrity level
Annex A (informative) As Low As Reasonably Practicable (ALARP)
                      and tolerable risk concepts
Annex B (informative) Semi-quantitative method
Annex C (informative) The safety layer matrix method
Annex D (informative) Determination of the required safety
                      integrity levels - a semiqualitative
                      method: calibrated risk graph
Annex E (informative) Determination of the required safety
                      integrity levels - a qualitative method:
                      risk graph
Annex F (informative) Layer of protection analysis (LOPA)

Gives information on: - the underlying concepts of risk, the relationship of risk to safety integrity, - the determination of tolerable risk, - a number of different methods that enable the safety integrity levels for the safety instrumented functions to be determined.