FROM THE NEWS-LEDGER, MARCH 13, 2013 –
By Steve Marschke
A mistake by a PG&E work crew led to overpressurization of a business customer’s gas line in January.
The utility company filed a mandatory “non-compliance report” about the incident with the California Public Utilities Commission, but local fire officials told the News-Ledger the event didn’t appear to pose a serious danger to the public.
The event occurred on Jan. 15 at a distribution business on the 1300-block of Jefferson Boulevard, when a PG&E crew responded to the report of a gas smell and a leak.
“During the leak repair, an employee inadvertently shut in the relief valve” on the customer’s line, “allowing pressure to build up in the service pipe,” said the PG&E report. “Approximately 250 feet of 1-inch and ½-inch plastic service was overpressurized for approximately one minute, until the crew corrected the error and opened the valve to allow pressure relief.”
The line was rated for a maximum operating pressure of 60 psig (pounds per square inch gauge. An attached gauge maxed out at its 150 psig reading, “however, the pressure in the service may have reached as high as 650 psig, which was the operating pressure in the upstream transmission line,” said PG&E.
After relieving the pressure, the crew took the equipment out of service for replacement. In the meantime, they provided portable compressed natural gas to the customer.
Fire Marshal Brian Johnson noted that the involved lines were fairly small, and the mishap occurred outdoors.
“It was a small distribution line,” he told the News-Ledger. “Less than one inch. With natural gas, it’s half as light as air, so it will go up into the atmosphere. It’s when it gets up in a building – a room or something – that’s when it gets dangerous.”
Fire Chief Al Terrell agreed, comparing it to a fatal gas line explosion in the Bay Area in 2010.
“From my point of view, it wasn’t as big an event as it may have seemed,” said Terrell. “Everything was well taken care of by the first responders, (city) public works and PG&E. It was nowhere near what happened in San Bruno.”
Copyright News-Ledger 2013