Uncertainty evaluation of data to be used in risk assessment techniques

In this paper some aspects will be discussed with the aim of examining the reliability of data with reference to a Fault tree approach for risk analysis in industrial applications. Analysis has been carried out by using data from a high level commercial data base which is of large use for maintenance and risk analysis in order to evaluate both failure rate of components and its uncertainty when a fixed confidence limit is set. Comparison has been carried out with reference to different categories of components to be inserted in risk analysis, like instrumentation of different type, engines, pumps and motors. Particular attention will be paid to instrumentation for process control. Some further consideration will also be done with reference to the available data selection and merging in order to get the best reliability of computed results and to improve the efficiency of collection of experimental data to be used for maintenance and risk analysis.