Posted on May 16, 2017

Oakland: PG&E Gas Crews Testing More Efficient, Faster Way to Reach Underground Pipes

By Teresa Jimenez

Reaching underground pipes is a necessary job for gas service work. Excavating means jackhammering asphalt and hauling away dirt, rocks and other debris. Then the area has to be paved, which can be delayed several weeks depending on work schedules.

PG&E crew members core an 18-inch diameter hole in the asphalt and remove dirt and debris using a dry-vac truck to reach the pipe. (Photos by Michael Paustian.)

But there’s now a less invasive way to excavate, and PG&E is testing the new technology. It’s happening in Oakland where a general construction team is using special tools and a new technique to proactively replace service tee caps — underground pipe pieces that link together other pipes.

The new “keyhole” technology not only enhances safety but is more efficient and environmentally friendly because it eliminates larger digs and restoration.

To gain access to service tee caps, crews typically excavate a 4-foot by 4-foot trench, or about the size of a folding table. The new technology allows crews to dig a much smaller hole —18 inches in diameter or the size of a basketball hoop — through the asphalt or sidewalk. A dry vacuum truck then sucks the dirt and other debris from the hole. The tee cap is replaced using long-handled tools.

Once the replacement is complete, the hole is backfilled with the excavated material stored in the vacuum truck. The removed 18-inch asphalt piece is placed back on the hole and sealed into place with a pavement bonding grout that’s stronger than traditional asphalt.

PG&E worked with the city of Oakland to allow the work to be done under a single permit, further capturing efficiencies by not requiring individual permits for each location. This allowed crews to efficiently move from job site to job site, completing 250 replacements since February. Starting in June, PG&E will perform the same type of excavation in Berkeley as well.

The cored piece of asphalt has been placed back onto the hole like a puzzle piece and sealed with a special grout that is stronger than traditional asphalt.

The projected savings over three years is estimated at $3.8 million. Each replacement takes an hour or two, with crews performing about eight in a day.

“One tee cap replacement takes an hour or two, and we can do about eight in a day. We can be in and out of a neighborhood in a day, minimizing disruption in a community,” said PG&E’s Kenny Conolley, a San Ramon-based gas supervisor.

The new process also is more environmentally friendly since crews reuse most of the existing materials.

Said Conolley: “I’m excited about this more efficient method being part of our future at PG&E.”

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"PG&E" refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation.
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