Defining and assessing safety functions performed by people

摘要

The design and safety assurance of systems require good requirements management. Within the nuclear industry, Safety Functional Requirements (SFRs) have become well-understood and form a central role as the design and safety case evolve. There are, established engineering methods for the identification, classification, format and substantiation of SFRs. Despite striving for engineered protection systems, humans continue to provide, support and contribute to this protection. Identifying the human 'component' in systems has advantages in terms of integrating with non-Human Factors disciplines, improving awareness of human factors within safety and design, and ultimately making system design safer. This paper describes the identification and assessment of safety functions that are performed by people. It presents some of the difficulties in trying to model and predict human behaviour compared to engineered system components. With emphasis on the nuclear industry, the paper discusses how the relationship between detailed hazard analysis and formally vested Operating Rules can be improved through the identification of safety functions performed by people.