Hazard Prevention by Forced Time Constraints

Minimal cut sets resulting from fault tree analysis (FTA) indicate basic events which, if occur together, can contribute to a hazard. For some applications we can extend event description with timing information and the hazard becomes enabled only if some particular timing relationships occur among the events of a given cut set. In this article we present how the timing information can be introduced to a fault tree and then exploited to identify additional timing requirements imposed on the controllable events of the system. Such requirements, if implemented, lead to the exclusion of some (otherwise feasible) scenarios of hazard occurrence