An on-line fault tree analysis for the continuous monitoring of industrial plant accidents

The Seveso Directive states that if a plant is subject to relevant accident risks it is necessary that the Plant Manager edits a Safety Report through which he can show that a risk analysis was executed in order to assess the risk related to the use of dangerous substances. There are a lot of well known techniques for executing the risk analysis of a process plant but only a few of these are quantitative, such as Fault Tree Analysis (FTA) that allows to assess the occurrence of a potential major event (Top Event). An On-line Fault Tree Analysis (OLFTA) was developed which, interfaced with the Distributed Control System of the plant, is able to assess the probability of the top event, taking into account of unavailable equipment, for failure or maintenance causes.