PR676-233801-R02 Pipeline Reliability Thresholds

Pipeline Research Council International Inc. (PRCI)'s Crack Management SRP has identified that circumferential cracking is a challenge for pipeline operating companies. The objective of PRCI NDE-4-24 was to create a framework to identify, assess and mitigate the risk due to circumferential cracking threats. Susceptibility to failure from circumferential cracking is linked to (1) circumfer-ential cracks subject to increasing axial or bending strains, or (2) growth in circumferential cracks at locations of residual strain. This project focusses on the first. No single in-line inspection (ILI) is capable of identifying circumferential cracks co-located within areas of increasing axial and bending strain. While bending strains are reliably detected with inertial mapping in-line inspection (ILI/IMU), identifying increasing strain due to subsidence or ground movement geotechnical requires separate expertise. Combining these into a framework to estimate the risk of a pipeline failure from circumferential cracks is the focus of this project. This report summarizes a methodology to develop a reliability criteria to evaluate risk for use in the PRCI NDE-4-24 circumferential crack framework. Once the risk for a given pipeline segment is estimated, the resulting values are compared to a reliability criteria to determine whether the risk is acceptable, or whether mitigating strategies must be initiated. As a result, a reliability criteria is an essential element to the framework and integrity program decision-making.