In order to prevent leakage accidents in a oil storage tank, it is important to be acquainted with the state of deterioration. Unless the tank is maintained properly, estimation of the life may be indispensable to avoid accidents. In this paper, the life is defined as time necessary for a deepest corrosion pit on a steel plate to penetrate through the thickness.
Method to predict the life are shown on the bases of statistics. Some data on corrosion rate of bottom plates are reviewed and a new interpretation about scattered values appeared in such data is introduced, which will be useful to estimate the reliability of predicted life. Extremal statistics is also reviewed to estimate the maximum corrosion depth on the outer surface of bottm plate and an usage of double exponential distribution is shown in an example for life prediction.
