IEC 61508/61511 and SIL Determination

Topic Safety

CPD Hours 17.75

This is an IChemE approved training course and not delivered directly by the Institution. For more information about the course, contact the training provider directly.


Practical training in the appreciation of safety integrity level (SIL) determination to the technical requirements of IEC 61508/61511. It is aimed at responsible managers, engineers and designers, and provides an introduction to the standard, the basics of risk, methodologies for SIL determination, and some of the important factors involved including common pitfalls.

Additional dates are available visit the TÜV Rheinland Industrial Services website.

Learning outcomes

On completion you should be able to:

  • understand the concepts of SIL determination and the principles of IEC 61508 / 61511
  • explain the key terms and concepts which underpin a systematic consideration process for safety and protective systems in respect to SIL
  • understand the importance of SIL determination
  • determine where present practice is in line with the requirements of these standards and identify where improvements are necessary
  • implement the SIL determination.

Who will benefit

Process design engineers, electrical, control and instrument engineers, designers, safety managers. Advisors and technical managers with responsibility for managing risk.

Course outline

  • Introduction to the standards and their background
  • Scope and applicability
  • Functional safety and IEC 61508/61511 interpretation
  • IEC 61508/61511 basic principles refresher
  • The concept and importance of SIL determination
  • Risk concepts and criteria, risk aversion, tolerability (with exercise)
  • Hazard identification, assessing frequency and consequence, modification list (incl. example)
  • Risk graph approach (with exercises)
  • LOPA use with examples
  • Fault trees and demand trees (using exercises)
  • The impact of humans in the equation and sources of fault tree data
  • Dependency demands, layers etc.
  • The ‘pros and cons’ of the differing approaches to SIL determination
  • Introduction to the CASS scheme
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