Symposium held on PG&E's hydrostatic testing

PG&E prepares to water test pipelines in Mountain View
May 6, 2011 7:49:45 PM PDT
PG&E plans to pressure test more than 150 miles of pipeline by the end of the year. It's part of an effort to prevent another explosion like the deadly blast in San Bruno. However on Friday, the California Public Utilities Commission grilled PG&E and pipeline experts on the plans.

Pipeline testing expert John Kiefner told the CPUC that water testing or smart pigging of the ruptured San Bruno pipeline would have caught the faulty weld before the deadly explosion. Line 132 was never water tested or smart pigged. It was tested for corrosion with a system called direct assessment.

Water testing is very expensive, between $150,000 - $500,000/mile. PG&E was not required by regulation to conduct the water testing or smart pigging (a robotic machine inserted into the pipe, generally using magnetic resonance to identify pipe weaknesses). But the state Fire Marshal's office told the CPUC that one or the other of those tests is necessary for baseline safety, and to restore public confidence in the CPUC and PG&E.

A handful of pipeline experts and PG&E representatives addressed the CPUC Friday morning at its hydrostatic (water) testing symposium. The symposium is both to educate the commissioners and the public about the coming water testing program. Tests in Mountain View and Antioch are already in the works. The Mountain View test will be on Monday. Antioch will be May 16, with a second test two days later.

Kiefner showed CPUC commissioners pictures of pipes that failed when put trough a high pressure water test. Kiefner has helped PG&E plan for that kind of testing on 150 miles of pipe this year. The tests should help reveal pipe defects like the weak weld that contributed to the rupture of San Bruno's Line 132.

"I believe it would have found the faulty weld," said Kiefner.

Line 132 was never water-tested after put in the ground in 1956 -- PG&E was not required to. The pipes PG&E is about to start testing are similar to Line 132 and have incomplete test records. Kiefner said the pressure tests PG&E has planned should remove any doubt about a rupture on those pipes.

"You can never say never, but I really think this is greatly going to increase the reliability of the system and our confidence in it," said Kiefner.

"Dr. Kiefner is the leading expert in the country. He wrote the book on this testing," said CPUC Commissioner Mike Florio.

Florio said the public should feel confident that the best and brightest are working on how to prevent another pipeline accident. Pressure tests are the first step.

"It took a little while to get there, but I think Mr. Campbell from PG&E said 'We don't expect any failures.' That's the answer I wanted to hear. If they happen that's not a bad thing because it means we found a problem before it happened," said Florio.

PG&E is pressure testing the 150 miles in 95 separate segments. It expects to do 15 tests per month, finishing by the end of October.

The NTSB's final report with a probable cause of the San Bruno explosion is expected before the one-year anniversary in September.


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