WIT Press

Risk Analysis And Acceptability Criteria


Free (open access)

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639 kb


M. Guarascio, M. Lombardi, G. Rossi & G. Sciarra


The basic concepts and tools for the Quantitative Probabilistic Risk Analysis are presented. The rationale of the risk acceptability criteria is discussed in the case of rail tunnel safety in Italy. Keywords: Quantitative Probabilistic Risk Analysis, risk acceptability criteria. 1 Introduction In general, risk analysis is a risk assessment tool which initially has been developed to investigate the safety of potentially dangerous industrial processes (e.g. in the chemical industry) or potentially dangerous industrial plants (such as nuclear power plants). Nowadays Quantitative Probabilistic Risk Analysis is a powerful common tool in many sectors of engineering design and operating practice both industrial and civil. The application of risk analysis should help to establish a proactive safety strategy by investigating potential risks. This safety strategy was to replace merely experience-based concepts learned from incidents or accidents, that had already happened. Generally speaking, risk analysis deals with potential negative consequences of events that could occur when considering a technical system in a social environment. The only option in such a situation is to develop a representative model of the risks associated to the system in question. As there exists an unlimited number of possibilities of how dangerous effects may develop it is impossible to take all possible situations into account; therefore the only investigation is restricted to a limited number of selected representative scenarios. For that reason it should always be kept in mind that risk analysis is a model relying on preconditions and assumptions and is not a copy of reality. Nevertheless risk analysis provides a much better understanding of risk-related processes than merely experience-based concepts may ever achieve.


Quantitative Probabilistic Risk Analysis, risk acceptability criteria.