Bayesian sample size determination for inspection of general corrosion of process components

A Bayesian approach-based method is proposed for calculating the minimum size of a sample to assess, with a specified precision, the integrity of process components suffering from general corrosion. The proposed method ensures that the error in the posterior estimate of the mean does not exceed a pre-defined acceptable margin of error at a specified confidence level. An analytical formula to estimate the sample size is introduced. The sample size obtained using the proposed method is smaller than a sample size obtained using the classical method with same confidence level. This reduces sampling inspection cost without affecting the precision of the estimate.

► A method is proposed to determine sample size for inspection of general corrosion. ► The proposed method is based on Bayesian updating approach. ► An analytical formula to estimate the sample size is introduced. ► The effect of prior knowledge on the sample size determination is discussed.