Forensic Engineering Investigation of Factors Contributing to the Explosion of an International Natural Gas Pipeline
Keywords:pipeline, hydrogen embrittlement, hard-spot, cathodic protection, operating pressure, maintenance, natural gas pipeline, pipeline inspection, forensic engineering
Following the explosion of a natural gas pipeline that resulted in extensive property damage, personal injury, and loss of life, a forensic engineering investigation was performed to determine factors that signifi-cantly contributed to the failure. Metallurgical analysis of the failure region resulted in the conclusion that the pipeline rupture was caused by hydrogen embrittlement acting on hard spots created during manufactur-ing. The next phase of this investigation involved root cause analysis of factors contributing to the pipeline rupture as well as evaluation of missed risk-reduction opportunities of the nondestructive analyses employed. It was ultimately determined that hydrogen embrittlement, caused by improper operation and maintenance procedures, resulted in an overabundance of hydrogen from excessive cathodic protection. Additionally, excessive operating pressure exceeded the resulting degraded ultimate capacity of the pipeline, which then manifested in the rupture of the natural gas pipeline and the ensuing explosion. It is recommended that op-erators exercise due diligence by considering the age of a pipeline when determining appropriate operating, monitoring, and maintenance procedures.
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