Abstract: This article attempts to research the factors affecting the failure probabilities of the atmospheric oil storage tanks in China more scientifically. A multi-hierarchy gray comprehensive evaluation method was developed based on the AHP and gray comprehensive evaluation method. Based on the RBI technology, a model was built for assessing failure probabilities of the atmospheric oil storage tanks. On the basis of coefficient correction method, the evaluation index system was divided into three levels, the first grade target layer A,the second grade element layer B,and the third grade index layer C.The weights of the evaluation factors can be calculated by using AHP. The gray comprehensive evaluation method was applied to a practical case. The results gained from the trial application demonstrate that the covered risk problems caused by traditional scoring ways can be avoided by using the evaluation method developed by the authors, that at the same time, the model ranks the factors affecting the equipment correction coefficient.

Key words: atmospheric oil storage tanks, risk based inspection (RBI), failure probability, analytic hierarchy process(AHP), grey comprehensive evaluation method