EFFICIENCY OF SAFETY BARRIERS FACING HUMAN ERRORS

This paper proposes a new approach for assessing the efficiency of barriers and of barrier removals. Facing defences in depth organized by physical barriers implemented on the human-machine system or by immaterial barriers such as procedures to be applied, barrier removal is an intentional human error and consists in not respecting the existing barriers of the human-machine system. An approach is then proposed to assess the THERP and ACIH methods. Some examples are proposed presenting probabilities of success of different barrier removals.