C2024-21001 Impact of Corrosion Growth on Effective Flaw Dimensions

Thomas Bubenik, Steven Polasik, Ben Hanna - This paper summarizes the results of a sensitivity study conducted on corrosion clusters on a steel pipeline, specifically (1) the change in cluster effective length as the pits that make up the cluster grow and (2) the effect of changes in effective length on the remaining life and the likelihood of a release as determined using a Probability of Exceedance (POE) method. Two growth scenarios are considered: pits that grow at the same rate versus pits that grow at a depth-based corrosion growth rate (e.g., deeper pits grow faster than shallower pits). The study shows that, in both scenarios, the effective lengths of long clusters often shrink with growth, while those of short clusters can increase or decrease. A case study demonstrates the impact of the results for an operator whose pipeline contained clusters with very long effective lengths. The change in the likelihood of a release is compared with and without considering changes in effec