Pipeline Pressure Hike Violated Rules

Wednesday, February 23, 2011 @ 07:02 PM gHale


After spiking pressure on a natural gas pipeline, Pacific Gas and Electric Co. (PG&E) should have inspected the lines for weak welds, according to federal regulations.

Natural gas safety rules said the utility would have had to inspect the pipeline in San Bruno for weak welds after spiking the pressure on the line in 2003 and 2008, according to a report provided to the San Francisco Chronicle by federal regulators.

Federal reports said a seam in the pipeline was the source of the Sept. 9 blast that killed eight people and left dozens of homes uninhabitable.

Had they done an inspection, they would have most likely discovered a seam, but PG&E conducted a less expensive test in 2009 that would have detected only corrosion in the pipeline, according to the published report.

Safety experts said the spikes may have weakened the lines and made them more prone to rupture.

“There is an obligation to say something is not right here,” Richard Kuprewicz, a Redmond, Wash., pipeline safety consultant, said of PG&E’s practices leading up to the blast. “Now you have to take the appropriate action, what is the plan to deal with this?”

The U.S. Pipeline and Hazardous Materials Safety Administration issued a statement that concluded any intentional boost that pushes an urban gas transmission line beyond legal limits requires the operator to inspect for weakness in the line.

A pipeline operator “may not intentionally exceed (maximum allowable operating pressure) for any reason,” the agency said in its statement.

The increases in pressure on the San Bruno pipeline were necessary to continue operations on the pipeline, said PG&E spokesman Joe Molica.

There was also a key difference between “continuous operation of a pipeline at a certain pressure, and occasional brief fluctuations in pressure,” he said.



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