Pacific Gas and Electric Co. (PG&E) said Monday part of its transmission pipeline picking up Southwest supplies at the California-Arizona border failed a hydrostatic test earlier in the day. Crews were working to replace a one-mile segment of Line 300 B in a remote part of Bakersfield, CA, in the southern central valley region.

This was the first failure experienced since PG&E began the hydrostatic testing program at the behest of state regulators earlier this year (see Daily GPI, May 5).

Crews are removing water from the pipe and preparing to replace the damaged segment, according to a PG&E spokesperson. “This work is expected to last throughout the week, and the line will be retested once the segment has been repaired,” the spokesperson said.

Failure occurred in a 34-inch diameter section, operated at 757 psig, that was installed in 1950. A double submerged arc-welded longitudinal seam failed during the test, the utility said. At the time of failure, the test pressure on the segment was 998 psig, which is 94.9% of the pipeline’s specified minimum yield strength. Crews had planned to pressurize the section up to 1,040 psig.

PG&E said it has conducted more than 60 hydrostatic pressure tests on nearly 120 miles of pipeline throughout its service area since April. “All of these tests have been successful and no weaknesses have been found prior to [Monday],” the spokesperson said.

“We are conducting hydrostatic pressure tests to identify any weaknesses that may exist so that we can immediately repair, replace and retest the lines.”

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