[californiadisasters] PG&E Surge May Have Stressed San Bruno Line in '08

PG&E surge may have stressed San Bruno line in '08

Jaxon Van Derbeken, San Francisco Chronicle Staff Writer

San Francisco Chronicle January 9, 2011 04:00 AM Copyright San Francisco Chronicle. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Sunday, January 9, 2011

Pacific Gas and Electric Co. briefly raised the pressure on its San Bruno natural gas line to the brink less than two years before the explosion that killed eight people - an action experts call a "huge gamble" that they fear made the pipe more susceptible to failure.

A Chronicle investigation into events before the explosion led PG&E officials to reveal that for two hours on Dec. 9, 2008, the company intentionally boosted gas pressure to the maximum legal limit of 400 pounds per square inch. That was more pressure than PG&E has ever acknowledged using on the line, which it normally ran at 375 pounds per square inch.

The utility initially explained that it had boosted the pressure because federal regulations required it to do so, but later conceded that its interpretation was inaccurate. It then explained that the spike was "part of our operating practice."

This is the first time the company has ever acknowledged running the San Bruno line at its legal maximum - a level now under scrutiny by federal investigators in light of revelations that PG&E had erroneous records about the pipeline's characteristics.

The next time the pressure exceeded 375 pounds per square inch on the line was on Sept. 9, when a malfunction caused a surge to 386 pounds - a spike that coincided with the deadly explosion and fireball in San Bruno that destroyed 38 homes.

View entire article here: http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2011/01/08/MNVM1GTR1V.DTL#ixzz1AZleEKhh

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