Regulatory Next Steps in Addressing Pipeline Seam Weld Challenges

Abstract

Since the beginning of pipeline transportation operations, pipe seam integrity and mitigation measures to prevent pipe seam leaks and failures have been a challenge for the industry and government regulators. The Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Office of Pipeline Safety (OPS) has investigated leaks and failures, issued advisory bulletins, funded research projects, and developed regulations for integrity assurance of pipe seams during pipeline design, construction, and operations and maintenance (including integrity management). This report will discuss PHMSA’s pipe seam efforts to date, framing leak and failure history, past advisory bulletins, United States (U.S.) Legislative and Executive actions (statutory actions), recent U.S. National Transportation Safety Board (NTSB) findings, accident investigation findings, and ongoing research for pipe long seam welds. PHMSA will review challenges and summarize past and possible future regulatory considerations based on the research findings to date and pipe seam incidents. In 2011 PHMSA initiated a long seam research project titled “Comprehensive Study to Understand Longitudinal ERW Seam Failures.” The program goals are to assist PHMSA in favorably closing U.S. NTSB Recommendations P-09-01 [1] and P-09-02 [1], which were issued after the Carmichael, Mississippi pipeline electric resistance welded (ERW) seam rupture, and recommended that PHMSA conduct a comprehensive study of ERW pipe properties and implement measures to assure that they do not fail in service. The research objectives for Phase 1 were to review current ERW seam integrity assessment methods (hydrostatic testing and in-line inspection using a crack-detection tool) to understand measures needed to consistently identify subcritical seam defects in order to act in time to prevent ERW seam ruptures. Phase 2 objectives are to develop hydrotest protocols, improve anomaly characterization criteria, develop seam defect growth models, and develop seam integrity management techniques. Phase 1 was completed in early January 2014, and Phase 2 is scheduled to be completed in late fall 2014. To date, this study has led to 17 technical reports. These reports are publically available on the following PHMSA website: http://primis.phmsa.dot.gov/matrix/PrjHome.rdm?prj=390.