PG&E Should Test 705 Miles of Pipe

Monday, May 2, 2011 @ 05:05 PM gHale


Pacific Gas & Electric (PG&E) should replace or perform water pressure tests on 705 miles of its oldest natural gas pipes because state regulators have “become increasingly uncomfortable” with the utility’s claim that it can set safe pressure levels for those pipes using “assumptions.”

If regulators approve the recommendation from the staff of the California Public Utilities (PUC), the hydro-tests could disrupt gas service for untold numbers of PG&E’s customers, cost the company $350 million and take five years to complete. Replacing pipe also could inconvenience customers and typically costs far more per mile.

The commission had ordered PG&E to calculate safe pressure levels for its gas lines based on the pipes’ construction, inspection and other records. In response, PG&E last week said it “does not believe it will find specific records of every component” and asked to base the pressure levels on its assumptions about the lines, using what files it has.

That request did not go far as Richard Clark, director of the commission’s safety branch, said “we do not believe that reliance upon indirect evidence of the material condition of PG&E’s natural gas transmission system is sufficient.”

PG&E spokeswoman Brittany Chord said the company “will be working with the commission to better understand the impacts this may have on PG&E’s operations.” She said “we have already taken many steps to further enhance the safety of our system,” which includes reducing the gas pressure in 10 transmission pipes at the commission’s direction.

Concerns about PG&E’s pipe pressure levels are the result of the Sept. 9 San Bruno gas line explosion, which killed eight people and destroyed 38 homes. While investigating the blast, federal investigators discovered the pipe, which had welding defects, burst at a pressure that was less than what PG&E thought was safe.

In addition, the utility’s records mistakenly described the ruptured segment as not any welds along its length, an error investigators said could have fooled the company into thinking the pipe was stronger than it really was.

In January, the commission ordered PG&E to locate records to prove it has set safe pressure levels for all 1,805 miles of its urban gas lines. But PG&E failed to meet the March 15 deadline to find all of the files, especially for its older pipes, many of which went in to the ground when record-keeping rules were more lax than they are today.

Because it didn’t meet that deadline, PG&E could face a $3 million fine. It also could face more fines if the PUC determines its record-keeping practices violated the law.

PG&E has vowed to hydro-test or replace 152 miles of pipe with characteristics similar to that of the burst San Bruno segment this year. However, the directive that it hydro-test or replace an additional 553 miles, would mean more work and expense.

Experts estimate hydro-testing, which involves forcing water at high pressure into pipe segments to look for leaks, costs $150,000 to $500,000 per mile. The procedure also typically requires removing a line from service for a week or longer.



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