A novel accident model and its application to hazard analysis

An accident model which is used to describe accident causation and evolvement is the foundation for system safety research. Most traditional accident models just research into accident causation, and can not effectively conduct hazard analysis. The traditional hazard analysis methods are incomplete and can not implement comprehensive hazard analysis of a dynamic operational process. To address this need, the concept of operational process hazard analysis (OPHA) is presented. Based on cybernetics, system safety can be viewed as a control problem. For the purpose of modeling accidents, the concepts of energy-flow and information-flow are redefined. Employing the concepts, this paper considers energy-flow and information-flow as the two components that control human- machine-environment within an operational process. The cause of accidents is treated as safety-critical energy-flow or information-flow failure in an operational process. As a result, a novel accident model named energy-flow and information-flow failure accident model (EIFM) is proposed. Relying on EIFM, OPHA can be carried out. The result shows that the factors that contribute to failures of normal safety-critical energy-flow or information-flow are also the ones that result in operational process hazards even accidents. EIFM-based OPHA extends the traditional hazard analysis methods, and can effectively prevent accidents as well as support accident investigation.