WIT Press

The Assessment Of Risk In Industrial Installations: The Risk Severity Index


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WIT Press


E. Planas, J. Arnaldos, B. Silvetti, A. Vallée & J. Casal


A risk index (Risk Severity Index, S) has been devised to allow the assessment of the risk level originated by a given installation or site over the affected zone. A set of threshold levels for thermal radiation, toxic concentration, and overpressure, together with the probabilities and frequencies associated with critical events and their effects, have been the basis for calculating the values of S. A computer tool has been designed to perform a quick calculation of the diverse Risk Severity Indexes (for a critical event, for a dangerous phenomenon, for a type of effect and for the whole installation) and to plot a map of the risk severity levels around the site. The methodology has been applied to diverse test cases and it has proved to be useful for risk assessment, for comparative studies and for land use planning. Keywords: risk analysis, risk index, accident severity. 1 Introduction An extensive bibliographical search proved that, although a number of \“risk indexes” exist, none of them allows the representation of the severity of the risk associated to an industrial installation. This paper describes the so-called Risk Severity Index, a parameter representing the severity of the diverse possible accidental scenarios. Certainly, including and summarizing in a single parameter all the factors having an influence on the risk associated to a given installation implies a


risk analysis, risk index, accident severity.