Chevron fire ignited by idling rig?

The Richmond refinery fire that sent more than 9,000 people to emergency rooms could have been touched off when a cloud of flammable vapor reached an idling and abandoned Chevron fire truck, investigators said Tuesday.

A company surveillance videotape that captured the two minutes before the blast showed that a dense vapor cloud fueled by the leak expanded to more than 200 feet wide and 200 feet high at the refinery’s Crude Unit No. 4, surrounding as many as a dozen workers, who fled just in time.

“They were enveloped by a vapor cloud that later ignited when it found an ignition source,” said Don Holmstrom, an investigator for the U.S. Chemical Safety Board, which is overseeing the fire investigation. The inquiry has involved 50 interviews and scrutiny of thousands of pages of documents.

Holmstrom noted that a likely source of ignition was the idling rig’s diesel engine, but stressed that exactly what set off the cloud may never be known for certain.

Diesel engines have been tied to earlier refinery accidents, including the devastating 2005 explosion that killed 15 workers and injured scores of others at the BP refinery at Texas City, Texas. That accident occurred when an idling diesel pickup truck drew in flammable hydrocarbon vapors and exploded, hitting trailers full of workers.

Key lines of the investigation are the decision to leave the crude unit in service after the leak was discovered and the determination last fall that the 40-year-old, 8-inch pipe could be safely left in service even while a companion line was replaced because of corrosion, said Daniel Horowitz, managing director of the Chemical Safety Board.

Chevron considered replacing pipe
http://fuelfix.com/blog/2012/08/14/chevron-considered-replacing-pipe/
August 14, 2012

hevron officials initially deemed the pipe that failed dramatically last week, causing a major fire at its Richmond refinery, as possibly needing replacement last year but ultimately cleared it for five more years of service, The Chronicle has learned.

Investigators with the U.S. Chemical Safety Board and other federal and state agencies have launched several inquiries into the Aug. 6 leak and fire. Both the damage and the investigations could leave part of the crude oil processing unit down for months.

A key issue is the decisions company officials made last fall, when the unit was shut down for annual inspection and repairs.

At the time, Chevron officials examined both the line that failed and a larger companion line linked to it, company officials said. Both pipes were fed from a 16-inch connection to the crude oil unit’s distillation tower and served to route hot hydrocarbons away for cooling and processing.

Pipe remained in service

The October inspection found unsafe levels of corrosion in the larger, 12-inch line, and officials designated it, along with its smaller companion line, for replacement, sources close to the investigation told The Chronicle.

But after reviewing inspection and other operation data, Chevron deemed the smaller, 8-inch-diameter line – the one tied to the leak and fire – fit to remain in service for five more years, the safety standard in U.S. regulations. Both pipes date to construction of the crude refining unit in the 1970s.

“They make decisions all the time. I don’t know if it was within the limits of corrosion. Hopefully it was within the limits,” said Jeff Clark, a field representative with the United Steelworkers union local at the refinery. “Obviously, the records will show what was scheduled for replacement and what wasn’t.”

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n this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the San Francisco Bay area hazardous for human entry after looking at the failed pipe that leaked and sent a towering plume of black smoke into the sky. Federal and state investigators are discussing plans for how to make the Richmond site safe so the faulty pipe can be removed for testing. Photo: U.S. Chemical Safety Board / AP

In this undated photo released by the U.S. Chemical Safety Board, structural damage is shown after the Chevron refinery fire in Richmond, Calif. Structural engineers have deemed the site of a Chevron refinery fire in the San Francisco Bay area hazardous for human entry after looking at the failed pipe that leaked and sent a towering plume of black smoke into the sky. Federal and state investigators are discussing plans for how to make the Richmond site safe so the faulty pipe can be removed for testing. Photo: U.S. Chemical Safety Board, Handout / AP

A friend who works at the refinery told me that the pipe in question was carrying diesel fuel at a temperature of 500 degrees and was wrapped with insulation. The pipe had been leaking and when an inspection crew peeled back the insulation, the leaking fuel trapped under the insulation flash evaporated and was taken for smoke by the fire crew on station below. They hit it with cold water and cracked the pipe that was probably already weakened by the corrosion that caused the leak. The inspectors barely made it off the scaffolding; the fire truck was a total loss tagged at $700k.

The discussion among the employees centered on why the pipe that was being inspected was not shut down. Scuttlebutt has it that the damage won’t be repaired before the New Year. This is a constant problem with pipe wrapped in insulation. It is difficult to tell if rain water or condensation is working to corrode the pipes while being hidden from view.

Welcome to $4.00 gasoline.

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