PG&E begins long, slow pipe-testing process 

Nine down, hundreds left to go.

In recent weeks, PG&E has tested nine segments of its gas pipeline system that the company had no hard proof could withstand high pressures.

And, it turns out, they all could: So far, no pipes have buckled nor sprung leaks, according to PG&E spokeswoman Brittany Chord.

The utility company has been ordered by state regulators to test hundreds of miles of pipelines that they have never tested before — or at least have no record of doing so. The order came after one of its lines blew up a neighborhood in San Bruno in September, killing eight people and burning down dozens of homes. Since then, PG&E has admitted it had no records of ever testing that pipeline for strength.

PG&E has committed to testing about 150 miles of pipelines between now and October. All of those lines share similar welding characteristics and are around the same age as the one that blew up in San Bruno. Those are the pipes that PG&E considers highest priority to test immediately.

But last week, the California Public Utilities Commission ordered PG&E to test or replace far more than that. They must test or replace every mile of pipe that they have no records of ever testing before. PG&E has said that they lack complete records for about 700 miles of transmission pipelines through populated areas.

The tests, called hydrostatic pressure tests, cost between $150,000 and $500,000 a mile. At that rate, it could cost the company between $105 million and $350 million to test 700 miles.

The tests involve emptying a segment of pipeline of gas, and then filling it with pressurized water over at least eight hours. Technicians monitor the pressure, and if there is even a tiny drop of pressure, they know a leak has sprung. They also walk along the pipe to see if any leaks are apparent, Chord said.

The tests have required some rerouting of traffic, but have not caused any gas outages. The next test is expected Monday in South San Francisco. Some tests will also be conducted on lines through San Francisco in the next few weeks, Chord said.

Miles to go

So far, PG&E has hydrostatically pressure tested sections of pipelines in:

  • Antioch
  • Mountain View
  • Newberry Springs
  • Newberry-Baker
  • San Jose
  • Newark
  • South San Francisco

Source: PG&E

kworth@sfexaminer.com

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Katie Worth

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