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Corrosion Found in Failed PA Pipeline

Friday, May 6, 2016

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The federal agency devoted to pipeline safety has reportedly identified evidence of corrosion and a possible flaw in the weld coating of a natural gas pipeline that exploded just outside of Pittsburgh last week.

The blast, which occurred April 29 in Salem Township, Westmoreland County, PA, destroyed one home, damaged at least three others, singed acres of farmland and sent James Baker, 26, to a Pittsburgh hospital burn unit, multiple sources reported.

Baker, who suffered third-degree burns to 75 percent of his body, was upgraded to stable condition Wednesday (May 4), according to Pittsburgh news station WTAE.

The pipeline, operated by Houston-based Spectra Energy Corp., is part of a 30-inch-diameter transmission line said to cross half the United States.

The Pipeline and Hazardous Materials Safety Administration (PHMSA) told PaintSquare News Thursday (May 5) that it had issued an order for the company to take the necessary corrective action to protect the public, property and the environment from potential hazards associated with the recent gas transmission pipeline failure.

The pipeline that failed and three nearby pipelines are currently shut down under PHMSA’s authority, the agency said. The order requires the operator to take several immediate actions to determine the root cause of the incident and to ensure the safety of three nearby lines that could have been affected by the failure before they can be restarted.
 
PHMSA is investigating the cause of the failure, any factors that contributed to the severity of the incident and the operator’s adherence to Federal pipeline safety standards.  

"As our investigation continues, the order can be amended to direct the operator to take additional actions to address the root cause of this incident, as well as any other factors that may have contributed to the pipeline failure," the agency said.

"If PHMSA determines the operator has violated any federal pipeline standards, the agency can issue an enforcement action, levy civil penalties or refer the case for criminal investigation," it added.

Officials from Spectra Energy did not respond to a request for additional comment on the preliminary findings.

Initial Findings

PHMSA, part of the U.S. Department of Transporation, issued its Corrective Action Order (CAO) to Spectra Energy subsidiary Texas Eastern Transmission LP (TET) Tuesday (May 3).

The agency identified the affected segment as Line 27 of the Penn Jersey System (PJS) of the gas transmission pipeline.

The 36-year-old line is made up of X65 grade double submerged arc-welded pipe with a wall thickness of 0.404 inches manufactured by U.S. Steel, according to the report.

It is coated with Fusion Bond Epoxy with tape-coat coating at girth weld joints.

The line was said to be operating normally prior to the explosion, but the failure led to the “ejection of approximately 24.5 feet of feet of 30-inch pipe, which landed approximately 100 feet from the rupture site,” the CAO noted.

The explosion produced a 30-foot-wide, 50-feet-long, 12-foot-deep crater and a burn zone of a quarter-mile radius.

The cause of the failure is still unknown, but the investigation into the incident continues. The line had undergone in-line inspections (ILI) as recently as 2005 and 2012.

Creighton Welch, a spokesman for Spectra Energy, told the Pittsburgh Post-Gazette that no repairs or replacements were required as a result of the 2012 inspection, and the next scheduled ILI was in 2019.

“We also conduct routine field surveys of the corrosion prevention systems, including bimonthly inspections,” he said.

Coatings Failure, Corrosion Suspected

The section of failed pipe has been sent to an independent metallurgist for further study, and a third-party metallurgist (DNV GL) hired by Spectra Energy was brought to the scene of the blast that day.

However, according to PHMSA’s preliminary inspection, evidence of corrosion is visible along two of the circumferential welds—one at the point of failure and another excavated after the agency’s arrival at the failure site, it said.

“The pattern of corrosion indicates a possible flaw in the coating material applied to girth weld joints following construction welding procedures in the field at that time,” the CAO stated.

The Post-Gazette explained that while the pipeline manufacturer is usually responsible for coating the pipe sections, the weld joints are coated onsite and are likely to use a different material.

Welch added that tape coating, which refers to the method of coating, not the material, was “an accepted and preferred method of coating the pipeline weld joints.”

Richard Huriaux, a consulting engineer and former director of regulations and technical standards at PHMSA, also explained that corrosion is the second largest cause of failure, but he warned, “The fact that they found some corrosion nearby is neither here nor there at this point.”

Corrosion, he said, is “a hint, but it’s not a determination.”

Corrective Actions Needed

Line 27 and the other three lines of the PJS remain out of service while their integrity is assessed.

Before Line 27 can be restarted, the CAO calls for TET to expose at least two girth welds on both sides of the failure site to look for corrosion, inspect coating condition and examine other potential damage.

If the exposed pipe shows damage, crews must continue to uncover and inspect pipe until at least 10 feet of undamaged pipe has been exposed.

Pipe and coating are to be repaired or replaced as needed.

Additionally, the company must establish “adequate cathodic protection” in the area where the failure occurred.

A similar process must also be undertaken with the other three lines of the PJS.

The CAO also requires the mechanical and metallurgical testing and failure analysis of the failed pipe, to be witnessed by a PHMSA official, as well as the analysis of soil samples and any foreign materials found.

Moreover, the company must supply PHMSA with the results and information collected from the 2005 and 2012 ILIs related to the affected segment, including all associated re-coats and repairs, the report says.

The company has 30 days to report back on its testing and failure analysis and 60 days to inform the agency, based on recent ILI assessments, whether any anomalies were present that could have contributed to the failure or are present in elsewhere in the PJS lines.

   

Tagged categories: Cathodic protection; Coating failure; Coating inspection; Corrosion; Corrosion protection; Explosions; Health & Safety; Inspection; North America; PHMSA; Pipeline

Comment from Robert Bullard, (5/8/2016, 9:42 AM)

A 36 year old system needs to retrofitted with "sniffers" set in proportion to consequence of rupture. The technology exists to do this for a fraction of the price of the pipeline.


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