Statistical analysis of corrosion data of vaulted tank roof

The health status of the tank roof was evaluated to strengthen the management of storage tanks,to grasp the corrosion condition of the tank roof accurately.Generalized extreme value(GEV) distribution was adopted as statistical model for corrosion depth of the tank roof and the model for practical problems was built by statistic of the maximum.L-moments method was used for estimating the parameters of the model and the statistical law of the corrosion was analyzed.The results show that according to the calculation and analysis of the corrosion data of the five vaulted tank roofs from Shengli Oilfield,the maximum depth accords with the GEV distribution Ⅲ(Weibull distribution).The corrosion depth of tank roof fits the GEV distribution Ⅲ very well by Kolmogorov inspection.