Tuesday, March 15, 2011

Security risk in pipeline valve decision played down

Tuesday, March 15, 2011
WASHINGTON officials for the company, the California in a deadly pipeline explosion in September last year acknowledged Tuesday, four years before the accident you install valves rejected, which could have automatically switched or remote-controlled the flow of Erdgas.Pacific gas and electric co. employees were surveyed in a National Transportation Safety Board hearing on a 2006 memo, which said that the valves install "to ensure little or no effect on human safety or properties."Gas engineer Chih-hung Lee, author of the memo, said that he as only industry studies, not Government to reach its conclusions. Industry studies, he said that that most of the damage to gas-accidents pipeline occurs in the first 30 seconds.But if ruptured the pipeline Sept. 9 under a San Francisco suburb suburb, still gas feed a pillar of fire for an hour and a half, before flow could manually close workers. Eight people were killed, many injured, and dozens of houses destroyed."Investigators pointed to a study from 1999, Transport Department, which was previously warned that it be given a significant security risk, as long as gas on the fracture site and operators it not possible, manual valves rapidly close."All fire would have greater intensity and would have more potential for surrounding infrastructure damage, if it is constantly replenished with gas, "said the Government study." "The degree of the disruption in heavily populated and commercial areas would fire in direct proportion to the duration."Coroner's reports indicate that at least five people killed in San Bruno tried have to flee, when they died.Keith Slibasager, PG & E's Manager of gas system operations, said that it took control room staff about 15 minutes after the explosion, find out what happened and would have taken over an another 15 minutes to the gas with automatic or remote of controlled valves shut down. This is an hour consumes less than it took in San Bruno.Instead, about 12 minutes after the explosion, PG & E's dispatch center sent an off-duty employee which was explosion reported to investigate, but he not qualified to the manual valves necessary, feeding a huge fire, Switch off gas houses operate the Safety Board investigator, Ravi Chhatre, said.It took a team, the able to isolate the pipeline and 90 minutes for you, the valves 30 minutes after the break for the company crank dispatch, all stop gas, he said.PG & E officials acknowledged that after Lee's memo no effort made to check the valves. They said that since the disaster, the company to study a dozen of the valves in this year and their effectiveness has begun a pilot project for the installation.But Slibasager said there are potential safety drawbacks for the valves. If closed, he said you in the region widely used gas could cause failures that would put in homes and other buildings, from pilot light.The risk that when gas is again turned on, it could build in buildings in the pilot light is not immediately relit are saying.

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