The implementation of a probabilistic risk based inspection approach

Abstract

Equipment and units in the hydrocarbon and chemical process industry are subject to several deterioration mechanisms that could lead to a loss of containment. This work presents an enhancement of a risk based inspection methodology earlier presented by Kallen (2002). This risk based inspection methodology uses a stochastic gamma function to model the materials deterioration rate. Using the prior knowledge of the deterioration rate and a Bayesian updating method, a posterior material deterioration model is found for two cases: perfect and imperfect inspections. Then, this material deterioration model is used to estimate the optimal inspection, replacement and failure times. -- Estimating inspection times depends on the material deterioration rate, age of the equipment, original material thickness, and the number of previous inspections that were carried on. The optimal inspection time aims to reduce the risk of failure due to deterioration mechanisms by maintaining the value of the equipment's damage factor as low as possible.