WEDNESDAY, JANUARY 23, 2013
Heavy corrosion caused a pipeline wall to thin to one-fourth of its original thickness, leading to its rupture in December, a new federal report has found.
The National Transportation Safety Board (NTSB) released a preliminary report on Jan. 16 on the investigation into Columbia Gas Transmission's Dec. 11, 2012 pipeline explosion and fire in Sissonville, WV.
The explosion ignited a massive fireball and forced West Virginia State Police to close about a mile of Interstate 77 in both directions for approximately 18 hours.
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A pipeline that ruptured and ignited a massive fire in West Virginia in December had corrosion that deteriorated almost 75 percent of wall thickness in some areas, the NTSB said in a report. |
No one was killed or seriously injured, but the blast destroyed three homes and damaged several others.
Heavy Corrosion, Fractured Metal
The newest report stated that about 20 feet of a buried 20-inch diameter natural gas transmission pipeline (Line SM80) was separated and ejected from the the underground pipeline and landed more than 40 feet from its original location.
Heavy corrosion was found on the outside surface of the pipe near the midpoint and along the longitudinal fracture. Corrosion had thinned about a six-foot area of the pipe in the longitudinal direction and a two-foot section in the circumferential direction.
NTSB investigators measured the lowest wall thickness at 0.078 inches; the original pipe segment, which was installed in 1967, had a nominal wall thickness of 0.281 inches.
The original pipe had a fusion-bonded epoxy coating and cathodic protection.
The pipeline maximum allowable operating pressure was 1,000 pounds per square inch gauge (psig), and the operating pressure at the time of the rupture was about 929 psig.
The ejected section of pipe contained no girth welds and was fractured in the base metal along the entire longitudinal direction along the bottom of the pipe, according to the report.
Failed Alarm, 16 Alerts
Investigators previously learned that alarms didn't sound at Columbia's Charleston, WV, control room during the explosion. The report said that the first call to 911 after the explosion was made by someone at a nearby retirement home at 12:41 p.m. ET.
A control room worker first learned about the accident at about 12:53 p.m. ET after receiving a call from a Cabot Oil and Gas controller who had received a report of a rupture and fire from a field technician who was near the accident location.
Before the call from Cabot, the Columbia controller received 16 pressure drop alerts from the Lanham Compressor Station 4.7 miles upstream of the rupture. The alerts indicated discharge pressure dropping on all three pipelines in the SM80 system, reported the NTSB.
The day after the explosion, NTSB officials said that the control room received no "alarms" at the time of the blast; however, Peter Knudson, an NTSB spokesman, said on Jan. 16 that previous statement referred to more serious "critical alarms," and that the pressure drop alerts are among frequent, routine, notifications received by control room personnel.
He also said that the alerts came after the explosion, but before NiSource Inc., Columbia's parent company, learned of the accident.
"It indicates there were some pressure drops," said Knudson. "What [the series of alerts] means in the big scheme of things, that's part of our investigation—when did they come and how were they handled?"
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Police had to close a portion of Interstate 77 for 18 hours after the fire damaged the road. |
Columbia CEO Responds
Promptly after the NTSB released their report, Jimmy Staton, Columbia's executive vice president and group CEO, released a response stating that the company has taken specific steps to "thoroughly test, inspect and verify the safety and operational integrity of our system in the Sissonville area."
Staton's letter also said that "Columbia is committed to a thorough and complete analysis of all factors potentially contributing to the incident," and that the company is "doing everything they can to help each and every family in Sissonville impacted by this incident."
A few days after the blast, on Dec. 14, Staton released an open letter to the community stating that something "went terribly wrong with our natural gas pipeline near Sissonville" and pledging the company's determination to find out what caused the explosion.
Previous Investigation
NTSB investigators arrived in Sissonville the day of the explosion and spent several days collecting data, after which they tentatively determined corrosion to be a cause in the pipe's failure.
On Dec. 20, 2012, the U.S. Pipeline and Hazardous Materials Safety Administrator (PHMSA) issued a Corrective Action Order to Columbia Gas Transmission giving the company 365 days to perform a complete assessment and necessary repairs, including verifying cathodic protection equipment and testing stations on three pipelines, inspecting all critical valves, conducting leak surveys, and assessing coating integrity.
"After considering the age of the pipe, circumstances surrounding this failure, the proximity of the pipeline to populated areas, and public roadways the hazardous nature of the product the pipeline transports, the uncertainties as to the cause of the failure, and the ongoing investigation to determine the cause of the failure, I find that a failure to issue this Order expeditiously to require immediate corrective action would result in likely serious harm to life, property, and the environment," wrote Jeffrey D. Wiese, Associate Administrator for Pipeline Safety, in the Corrective Action Order.
Need Regulations 'With Teeth'
On Monday (Jan. 21), the Charleston Gazette published an editorial about concerns over pipeline safety written by Deborah A.P. Hersman, chairwoman of the NTSB.
According to Hersman, Sissonville is the NTSB's 125th pipeline investigation since the agency was established in 1967; since 2000, NTSB has completed 15 investigations into ruptures, leaks, line breaks, and explosions that "claimed 29 lives, injured dozens more, destroyed and damaged scores of homes, and caused more than $1 billion in damages."
"While our investigation into the cause of the Sissonville rupture is still underway, what especially concerns us in our investigations is that we see the same safety issues over and over again," wrote Hersman.
"These include corroded pipe, problems with pipeline operators' risk management programs, inadequate recognition of control system problems and slow emergency response by operators. We also see weaknesses in safety oversight when federal and state officials are stretched thin.
"Further, they need regulations with teeth and the resources to enable them to take corrective action before a rupture, explosion or spill, not just after."
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The Senate Commerce Committee plans to meet in West Virginia on Jan. 28 to discuss whether federal pipeline safety laws are doing enough to protect the public. |
The editorial comes just a week before a special pipeline safety meeting planned for Jan. 28 in Charleston, WV. Members of the Senate Commerce Committee, chaired by Sen. Jay Rockefeller, D-W.Va., will discuss whether federal pipeline safety laws that took effect last year provide adequate protection for the public and if they are being implemented fast enough.
11K Miles of Pipeline
Columbia Gas Transmission, a subsidiary of NiSource Inc., owns and operates approximately 11,453 miles of pipeline in Delaware, Kentucky, Maryland, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Virginia, and West Virginia.
Headquartered in Houston, TX, NiSource serves customers in at least 16 states with approximately 1.3 trillion cubic feet of natural gas flowing through its pipelines each year, according to the company.
Tagged categories: Accidents; Corrosion; Explosions; Health & Safety; NTSB (National Transportation Safety Board); Oil and Gas; Pipelines
