Hazard identification combined incidence measures

The acronym for chemical process quantitative risk analysis. It is the process of hazard identification followed by numerical evaluation of incident consequences and frequencies, and their combination into an overall measure of risk when applied to the chemical process industry. It is particularly applied to episodic events. It differs from, but is related to, a probabilistic risk analysis (PRA), a quantitative tool used in the nuclear industry... 

The use of hazardous states was not essential, but largely a matter of convenience, depending on which parameters were best estimated by analytical methods. For a few hazards, it seemed equally reasonable to score them as hazardous states or hazardous events. In some cases, the hazard identification process had generated two hazards that combined to produce an accident. For example, vehicle parked on the hard shoulder is a hazardous state that leads to an accident if the hazardous event vehicle drives down hard shoulder when closed occurs. To avoid double counting, only one of these hazards was included in the global risk scores. To mitigate the hazard, however, measures that reduce either the incidence of vehicles parked on the hard shoulder or the incidence of vehicles driving down the hard shoulder can be equally effective. 

The quantitative evaluation of expected risk from potential incident scenarios. It examines both consequences and frequencies, and how they combine into an overall measure of risk. The CPQRA process is always preceded by a qualitative systematic identification of process hazards. The CPQRA results may be used to make decisions, particularly when mitigation of risk is considered. 

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