SIL Determination 2009 - Dr Alan King

For a number of years, industry has been trying to apply the principles outlined in IEC 61508 and the various sector standards such as IEC 61511. In the field of SIL Determination, the standards provide suggestions of a number of different techniques including Event Trees, Risk Graphs, Safety Matrices, Fault Trees and Layer of Protection Analysis (LOPA).IEC 61508 and the related sector standards indicate the requirement to consider human failure. This can be found, for example, in IEC 61508 in the Overall Scope Definition requirements and again in the Hazard and Risk Analysis requirements. Nevertheless, those carrying out SIL Determination often struggle with the issue of the inclusion of human failure in their assessments, regardless of which technique they are using.This presentation reviews the issues relating to the inclusion of human failure in SIL Determination assessments together with some guidance and examples of how this can be achieved in practice