PG&E gas-main leak detected near Palo Alto

Leak is on Line 132, which caused the San Bruno blast, but is small and not expected to pose danger

UPDATE: On Tuesday (Nov. 8), PG&E crews determined that the leaking pipe was located under Page Mill Road's eastbound lane, between Hanover Street and Peter Coutts Road. One lane was blocked Tuesday as crews dug the pipe out; testing and repairs were scheduled to proceed Tuesday and Wednesday, according to spokesman Brian Swanson.


Workers examining a section of a PG&E gas main discovered a small leak near Palo Alto, a Pacific Gas and Electric Company spokesman said Friday (Nov. 4).

On Thursday night PG&E employees noticed a slow drop in pressure during a hydrostatic pressure test on Line 132 near Palo Alto. The line is the same one implicated in the September 2010 explosion and fire in San Bruno that killed eight people.

PG&E has been testing the line using a sophisticated water-pressure procedure to ascertain the condition of its mains as a result of federal and state findings related to the aging pipe infrastructure.

The Palo Alto/Stanford section of Line 132 runs parallel to the Junipero Serra/Interstate 280 corridor and down Page Mill Road between El Camino Real and near Interstate 280. Nearly 21,000 feet of the this section of 24-inch seamless pipe was installed in 1947 and about 2,700 feet has a seam weld and was installed in 1957, PG&E spokesman Brian Swanson said.

The drop in pressure has the characteristics of a small pinhole leak of approximately one millimeter in diameter. The leak poses no public danger and won't impact service, Swanson said.

The initial one-hour phase of the hydrostatic pressure test was being done to identify small leaks using water. Small leaks such as this do not pose safety risks and are easily repaired, according to PG&E.

The leak was detected during the initial phase of the hydrostatic pressure test when the pipe is tested at 75 percent of the test pressure for one hour.

Mains are pressurized beyond their maximum allowable pressure to expose leaks. The pressure at the time of the water leak was 525 pound-force per square inch gauge (psig) -- roughly one third higher than the normal operating pressure of 375 psig, PG&E said.

The main is currently operating at a reduced pressure of 300 psig, per a California Public Utilities Commission mandate until safety of the lines can be verified.

The company is working to precisely locate the leak. Nearly four miles of pipe being tested will have the water removed today, Swanson said.

PG&E on Sunday (Nov. 6) began putting a helium/air mixture through the pipeline to locate the leak workers will walk the line and search for indications of the helium, Swanson said on Monday. The company will excavate the area, make repairs and re-conduct the hydrostatic pressure test. The work is expected to take several days to complete, he said.

Using salvaged, reconditioned pipe was common in the industry in the 1940s and 1950s, but PG&E no longer engages in the practice, he said.

Related story:

Part of PG&E gas main in Palo Alto is salvaged pipe

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Like this comment
Posted by Pauly
a resident of Midtown
on Nov 4, 2011 at 1:45 pm

Nbc Bay Area was just in front of my home filming this story for the 7pm news.Hopefully nothing big!!

Like this comment
Posted by Cid Young
a resident of another community
on Nov 4, 2011 at 1:48 pm

"Leak is on Line 132, which caused the San Bruno blast, but is small and not expected to pose danger"

Same was said of San Bruno when leaking gas smells were reported.

Like this comment
Posted by danger
a resident of Adobe-Meadow
on Nov 4, 2011 at 1:59 pm

The only reason the leak is not dangerous is because the gas line is out of service right now.

Like this comment
Posted by mmmmMom
a resident of Downtown North
on Nov 4, 2011 at 9:02 pm

Holy moly!

Why didn't we all know about the testing?!? I went to a friend's house- near Colorado & Bryant - to help with gardening, The gas smell was overpowering! We were truly worried. We called the "gas leak hotline," but were totally brushed off. The woman answering the call was totally flip about it. (Reminded me of numerous comments made by San Bruno residents that many of them had made complaints about gas smells, but were not taken seriously.)

I asked for someone to call me back, & no one ever did. Glad to finally know what was going on.

Like this comment
Posted by danger
a resident of Adobe-Meadow
on Nov 4, 2011 at 10:35 pm

The leak was found in an empty pipeline (no gas in it). If you actually smelled gas, that was from a different pipe and you need to keep calling them back until they really do check it.

Like this comment
Posted by QUESTION!
a resident of Fairmeadow
on Nov 5, 2011 at 9:35 am

So where EXACTLY was the leak found -- what area? Near what streets?

Like this comment
Posted by mmmmMom
a resident of Downtown North
on Nov 5, 2011 at 8:58 pm

Yes, "danger," the local TV news also said there was no gas in the pipe. WHAT ?!?!?! We are positive we smelled gas...

So today I called back; was told "Well, when they flushed the pipe with water, there was some gas still in the line - so you may have noticed a smell."

Frankly, I am not very reassured. Again, I felt dismissed. Given what happened in San Bruno, you'd think they would be less flippant.

Like this comment
Posted by RIF
a resident of Barron Park
on Nov 5, 2011 at 9:25 pm

"Why didn't we all know about the testing?!? I went to a friend's house- near Colorado & Bryant - to help with gardening,"

According to the article, the section of pipe where they found the leak runs along Junipero Serra and down Page Mill from 280 to El Camino. If you were near Colorado and Bryant and smelled gas, it wasn't from this pipe.

Like this comment
Posted by Jay Thorwaldson
editor emeritus
on Nov 6, 2011 at 10:21 am

Jay Thorwaldson is a registered user.

As for "not knowing" about planned testing, a search of the website under "PG&E" comes up with six (6) news stories in the Palo Alto Weekly or online about the planned testing, in addition to an "On Deadline" column in the Sept. 30 Weekly asking why there is a half-century gap between automated shut-off valves in Canada and few such valves in the PG&E system. Where were state and federal safety guidelines, or enforcement? A constructive observation: Following local news in papers and online can be important, but blame for not knowing about some local issue or concern or danger usually belongs close to home and one's daily information or "news" habits. Regional TV news fails to cover local issues unless there is a danger, crime or other more exciting angle.

Like this comment
Posted by danger
a resident of Adobe-Meadow
on Nov 6, 2011 at 6:04 pm

PG&E found a huge gas line leak near Woodside today. KTVU news report: Web Link

Like this comment
Posted by Resident
a resident of Another Palo Alto neighborhood
on Nov 6, 2011 at 6:13 pm

This caused a huge mudslide on 280, read the link in the above post.

Like this comment
Posted by Walter_E_Wallis
a resident of Midtown
on Nov 7, 2011 at 10:54 am

Walter_E_Wallis is a registered user.

That Woodside leak causes me to wonder. If the test was water pressure only, there should have been no bursting. Bursting requires a compressible medium. A hydrostatic test usually requires first filling a pipe, then using a small displacement pump increasing the pressure until a leak happens, determined by a drop in pressure.

Like this comment
Posted by Nora Charles
a resident of Stanford
on Nov 7, 2011 at 10:13 pm

We received written notice in the mail about the testing, and phone calls. Tonight an automated phone message said that due to the testing residents might smell gas.

Like this comment
Posted by mmmmMom
a resident of Downtown North
on Nov 8, 2011 at 7:44 pm

Gee, Jay.... OUCH! Who said anything about blame?

Yeah, I did not know about it. Mea culpa. But then neither did 6 of the neighbors in my immediate block, nor any of the adjoining neighbors of my mid-town friend.

I consider myself to be erudite, & follow local news as well as I can. No, I don't read any paper every day - too busy! Life can be a regular news desert for us working, single Moms. (I do, however, listen to NPR daily on my drive home. So I try to not be too ignorant.) Main point: I am obviously not the only 1 who missed the testing notice. Maybe PG&E, & local city utilities, needs to be aware that their notification system needs improvement. A phone call would have worked, as would e-mail.

And to "RIF," I too wonder about the location. Question remains, however, WHERE did that smell, which was all over the aforementioned area, come from?

When I called the utility number, THEY said it was "from the testing."

I was hoping to get some info here...... guess not.
thanks anyway

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