Failure analysis of a natural gas pipeline rupture

The article presents a failure analysis of a natural gas pipeline rupture on September 10, 2010 in San Bruno, Calif. The pipeline belonged to Pacific Gas and Electric (PG&E). Soon after the rupture occurred, the National Transportation Safety Board (NTSB) sent a team to investigate. As part of the investigation, a 28-ft section of ruptured pipe along with the exposed ends of the pipe still underground were sent to the NTSB Materials Laboratory in Washington, D.C., for examination. In 1956, a segment of pipeline needed to be relocated by PG&E due to a subdivision development project. Segment 180, the relocated pipeline section, was constructed mainly from surplus and reconditioned DSAW pipe and involved roughly 1851 ft of Line 132 being moved west about 10 ft. However, at one location, the pipeline was constructed from six short lengths of pipe, often referred to as pups. Five of those pups, including the pup where the rupture would initiate, had properties that differed from DSAW pipe.