scope:

Purpose and field of application

The safety and availability of a technical system as well as the quality of a product can decisively be influenced by human actions in leading, regulating or servicing technical processes. For an overall analysis of a technical system it is therefore important to also consider the human influence additional to the technical components. This is being done by evaluating a technical system as a man-machine-system (MMS) - see VDI 4006 Part 1 (Bubb 92). The task of the HRA is to

• qualitatively analyze human actions thus identifying possible errors in actions

• identify weak elements, which provide the basis for appropriate counter measures, as well as

• quantify the reliability of human actions, which for instance allows to assess the effectiveness of remedial or counter measures (e.g. a safety gain) within the overall system

Therefore, the goal of HRA is an assessment of human reliability as well as an improvement of prerequisites for reliable human actions within a technical system, which also increases the availability of the technical system by decreasing the potential of human errors within the overall system. The human reliability in this context is always seen in connection with the technical system ("system component human being"); the aspect of human responsibility is not considered in HRA.