The National Transportation Safety Board (NTSB) said it plans to investigate this week why no alarms went off when a 20-inch diameter Columbia Gas Transmission pipeline exploded Tuesday near the rural community of Sissonville, WV.
At the Columbia Gas pipeline control center in Charleston, WV, “we understand that there were no alarms generated at the time of the accident,” said NTSB investigator Robert Sumwalt Wednesday following the agency’s first day of inspecting the rupture site near the pipeline’s Lanham Compressor Station near Sissonville. The site is about 15 miles north of the state capital, Charleston. The NTSB intends to visit the pipeline’s control center to examine records and interview operators.
Sumwalt said the NTSB did not yet know when the Columbia Gas pipeline was manufactured or last inspected.
The explosion on the Columbia Gas system created a crater 15 to 17 feet deep, according to Sumwalt. “When you look down into the crater, there’s a 20-foot, seven-inch gap in the pipe, and…that part was ejected out of the crater about 40 feet. That pipe is about pretty much flattened out,” he said.
The blast destroyed at least five homes and created several fires that were so intense firefighters were unable to move equipment near burning structures for a short period of time (see Daily GPI, Dec. 12). People were not home at the time of the explosion, so no significant injuries were reported. The blast also shut down a portion of Interstate 77. The interstate was reopened Wednesday after crews worked throughout the night to repair the damage, the Associated Press reported.
Sumwalt said two nearby gas pipelines — a 30-inch diameter pipeline that is 53 feet to the left of the ruptured Columbia Gas Line, and a 26-inch diameter line that is 134 feet to the left of the 30-inch line — were undamaged.
He said there were isolation valves both upstream and downstream of the rupture. They were “manually shut [off]” at about 1:45 p.m., about one hour after the explosion. In contrast, Sumwalt said the gas flowed for about 90 minutes following a fatal explosion on the Pacific Gas and Electric system in September 2010 (see Daily GPI, Sept. 17, 2010).
“We are planning [Thursday] to crate up the section of the pipe that was displaced. We might even end up cutting out a piece of either end of the pipe that is intact. All of this will be sent back to Washington for a detailed materials examination in the NTSB’s lab,” he said.
Sumwalt also said the agency will excavate about six to 10 feet to “try to get an idea of [what] the undamaged pipeline” looks like.
Moreover, the NTSB will survey the immediate vicinity of the ruptured area and the extent of the thermo radiation effects surrounding the area, Sumwalt said.
The NTSB investigators began arriving in Charleston Tuesday, just hours after the explosion, and are expected to remain in Sissonville over the next five to seven days (see Daily GPI, Dec. 13). The 10-member investigation team is being lead by Ravi Chhatre, an expert on pipeline operations, fire and explosions and emergency-response efforts.
“We have not spoken in detail to Columbia Gas at this point, but certainly that is something that we will be doing, and we will have their representatives here working with us for the next several days,” Sumwalt said Wednesday.
This was the second explosion on a NiSource pipeline in less than a month. In late November, an explosion on the Columbia Gas Co. of Massachusetts distribution system rocked Springfield, MA, damaging 42 homes and businesses and sending 18 people to area hospitals. Preliminary findings said a Columbia Gas employee “accidentally punctured” a pipe (see Daily GPI, Nov. 27). The blast is being investigated by the Massachusetts’ Department of Utilities, not the NTSB, because it occurred on a gas distribution system, which is under state jurisdiction.
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