A challenge facing pipeline integrity groups is how to determine the number of digs required to confirm the presence or absence of SCC in a pipeline section as part of the Direct Assessment process. A Bayesian statistical methodology has been developed to solve this problem. The pro-cess requires the definition of a probabilistic susceptibility, which is the likelihood that significant SCC exists somewhere on a pipeline. The SCCDA’s probability of success to find SCC also plays a central role. Based on the initial probabilistic susceptibility (prior probability) and the SCCDA success rate, the...
A challenge facing pipeline integrity groups is how to determine the number of digs required to confirm the presence or absence of SCC in a pipeline section as part of the Direct Assessment process. A Bayesian statistical methodology has been developed to solve this problem. The pro-cess requires the definition of a probabilistic susceptibility, which is the likelihood that significant SCC exists somewhere on a pipeline. The SCCDA’s probability of success to find SCC also plays a central role. Based on the initial probabilistic susceptibility (prior probability) and the SCCDA success rate, the Bayesian formula updates the likelihood of SCC, based on the results of the excavations. The number of excavations is determined when the absence of SCC is estab-lished to a predetermined confidence level. The required confidence level is left to the discretion of the pipeline operators.