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Material Matters Corrosion found in ruptured natural gas pipeline A section of pipe was found more than 40 ft from the site of the ruptured natural gas transmission line in Sissonville, West Virginia. Photo courtesy of NTSB. 14 MATERIALS PERFORMANCE May 2013 T he National Transportation Safety Board (NTSB) (Washington, DC) released a preliminary report on the December 11, 2012 rupture of a 20-in (508-mm) diameter natural gas transmission pipeline in Sissonville, West Virginia, that is owned and operated by Columbia Gas Transmission, LLC, a subsidiary of Columbia Pipeline Group (Houston, Texas). NTSB investigators found areas of wall thinning on the ruptured pipe that were consistent with external corrosion. According to the preliminary report, the 20-in diameter buried natural gas transmission pipeline (Line SM-80) ruptured at about 12:41 p.m. eastern standard time near Route 21 and Derricks Creek, about 112 ft (34 m) west of Interstate 77 in Sissonville. A 20-ft (6-m) section of pipe was separated and ejected from the underground pipeline and landed more than 40 ft (12 m) from its original location. The pipeline maximum allowable operating pressure (MAOP) was 1,000 psig, and the operating pressure at the time of the rupture was ~929 psig. The force of the released natural gas created a crater ~75-ft (23-m) long by 35-ft (10-m) wide and up to14-ft (4-m) deep. An undetermined amount of highpressure gas was released and ignited, which created two fame plumes. Damage from the ensuing fre covered a width of ~820 ft (250 m) across the pipeline and extended nearly 1,100 ft (335 m) along the pipeline. No fatalities or serious injuries resulted from the incident; however, three homes were destroyed by the fre and several other homes were damaged. Interstate 77 sustained thermal damage in both the northbound and southbound lanes, which were closed for ~18 h while the roadway surfaces were repaired. The rupture occurred in a pipe that was a part of a pipeline segment installed in 1967. The original pipe segment had a nominal wall thickness of 0.281 in (7 mm), a longitudinal electric resistance weld (ERW) seam located near the top of the pipe, and was manufactured according to API 5L X60. Corrosion protection was provided by a fusion-bonded epoxy coating and cathodic protection (CP). The natural gas flowing through the NACE International, Vol. 52, No. 5