Company testing 79 miles of two natural gas pipelines in wake of June’s rupture

http://www.pennlive.com/news/2016/03/company_testing_79_miles_of_tw.html

An Oklahoma-based company is conducting integrity tests on 79 miles of two of its Transco natural gas transmission pipelines in northern Pennsylvania to try to prevent a rupture like the one that occurred in June in eastern Lycoming County.

Williams Partners has determined the failure of a 24-inch transmission line was caused by a form of corrosion that began on the external surface, spokesman Chris Stockton said Monday.

The Pipeline and Hazardous Materials Safety Division of the U.S. Department of Transportation has yet to announce its findings.

Approximately 150 people were evacuated and Routes 118 and 42 were closed after 34 feet of the pipeline failed about three miles east of Unityville at 10:41 p.m. on June 9. No one was injured.

The escaping gas that was under pressure caused a loud noise but there was no fire or explosion. Initial 911 calls were for a plane crash.

Integrity testing is being done on the two pipelines in a common right of way between the Leidy underground storage facility in Tammerack in Clinton County and the Benton area in Columbia County, Stockton said.

The tests include the use of a smart pig whose sensors measure the thickness of the steel and sending water under pressure through the lines, he said.

A 14-mile segment of the line installed in 1963 in which the failure occurred has been isolated and pressure has been reduced in the second, he said.

“We want to be sure the same corrosion does not exist elsewhere,” Stockton said. “We want to take time to make sure everything is done right.”

The integrity testing, which has taken longer than normal due to the winter heating season, is anticipated to continue into spring, he said.

A third and in some places a fourth transmission line in the same right of way are not being tested because they are newer, he explained.

All the lines continue east from where the failure occurred into New Jersey where they connect with a Transco mainline, he said.

Williams is doing more work than the federal agency requires in a corrective action order issued last summer “to protect the public, property and the environment from potential hazards.” Stockton pointed out.