That's because the pipe is similar to the one that exploded in San Bruno and with incomplete test records, PG&E cannot validate its operating the lines at safe pressures.
This testing might never be done, if it weren't for the San Bruno explosion. Regulators ordered the utility to check all its records after the disaster. PG&E cannot find records confirming safe pressure levels for these 152 miles, so they will be tested or replaced. The cost is between $150,000 and $500,000 per mile. The CPUC has yet to decide whether its customers or shareholders will foot the bill.
On Monday, water will be forced into the pipeline at a pressure 200 pounds higher than its usual maximum allowable operating pressure. That will continue for eight hours. If it springs a leak, that's a sign there is a problem. This is all about trying to prevent another San Bruno-type accident.
Crews released air out of a cone connected to a 24-inch natural gas pipeline. The gas was already released and the air streamed through to make sure the gas is all gone. Next, the pipe will be cut in one place and about a mile and a half south, the cut end is capped and water pushed through, testing for weakness.
"This is basically an industry standard to safely pressure-test pipelines, make sure there's a significant margin of safety built into natural gas pipeline operations," said PG&E spokesman Brian Swanson.
The San Bruno explosion killed eight people and destroyed 38 homes. Line 132 was installed in 1956 and never water-tested. Instead, PG&E relied on a controversial system of spiking pressure. The NTSB has pinpointed a faulty weld as the point of rupture. Would it have been found if Line 132 had been water tested?
"That's something still being investigated by the NTSB, so anything related to what happened in San Bruno and why that happened, that's going to come out in the NTSB final report," said Swanson.
PG&E is trying to inform people near the test sites with letters and phone calls. But one man lives a half block away and says he got neither, and stopped to ask workers.
"I wanted to know what was going on. So, if it was a repair, or that sort of thing, and they sort of wanted to refer me to PG&E and they wouldn't answer any questions. And one guy said, 'Oh, I'm just a dumb truck driver,'" said Thomas.
Martha Jones of Mountain View, across the street, got both the letter and the call.
"Of course we're all concerned about this pipe situation. I think all over, that alone, because of the disaster that occurred and everyone's a little bit tentative," said Jones.
PG&E is also holding neighborhood open houses trying to inform people near the test sites. A segment from Antioch is next in line and preparation work will begin there next week.