Human reliability analysis
Human reliability assessment (HRA) is an assessment method which involves systematic prediction of errors that could be made by the humans within the system. A HRA aims to predict potential human errors when interacting with a system and eliminate or reduce their occurrence or effect, in order to maximise safety and performance of the in-service system.
The HRA should provide an assessment of the level of risk which is based on the identification of the error types, the likelihood of the error occurring, the opportunities to recover from the error and the likely consequence of that error. Different levels of screening (i.e. detail) should be used at different stages of the project.
Human Engineering has an established method for producing HRA. The HRA ensures that all potential errors have been identified, assessed and controlled. This requires the consideration of major accident prevention, as well as operator health and safety. The HRA should be based upon the tasks and functions specified during an initial Task Analysis. Error identification can incorporate the following techniques and tools: Failure modes and effects and criticality analysis (FMECA), Fault and event tree analysis, SHERPA, HEART, Hazard and operability study (HAZOP), and Human factors safety assessment.
Outcomes of the HRA can be entered into the hazard log and steps can be taken to reduce the risk associated with error occurrence to as low as reasonably practicable either by system re-design or the implementation of other controls or mitigations.