PR-201-084504-R01 Long-Term Composite Repair Study – Burst Test

Stress Engineering Services, Inc. (SES) was contracted by Pipeline Research Council International, Inc. (PRCI) to perform a study examining the long-term performance of composite repairs used for pipeline applications. The project reported here (PRCI study MATR-3-4 Long-term Composite Repair Study) included the installation of commercially available composite repair systems on pipe samples with regions of machined wall loss having depths of up to 75% of the pipe wall-thickness. Samples were fabricated using 12.75-inch x 0.375-inch, Grade X42 pipe material with each having a machined wall loss defect installed at one of three depths (40%, 60%, or 75% of pipe wall thickness). Following fabrication, the corrosion areas were reinforced with composite repairs and buried in the ground for up to ten years. The study sought to answer the question: how does the performance of a composite repair change over an extended period (up to 10 years) when subjected to environmental conditions representative of those encountered during pipeline operation? The composite repair systems were sourced from 13 different manufacturers and were installed on over 180 pipe samples prior to burial. Of these 13 reinforcement systems, four were tested to the end of the designated 10-year hold period. All samples underwent hydrostatic and periodic cyclic pressure testing while buried. Three unreinforced test samples, one of each wall loss depth, were burst at the onset of the study to provide baseline comparisons.