Get SF Weekly Newsletters

Wednesday, October 13, 2010

Feds Release Initial Report on San Bruno Explosion

Posted By on Wed, Oct 13, 2010 at 2:15 PM

click to enlarge SMI23LE
Smi23le
The National Transportation Safety Board today released its preliminary report on "Accident No. DCA10MP008"-- the San Bruno PG&E pipleline explosion and fire in plain English.

The brief document offers a telling glimpse as to how Sergeant Joe Friday would conduct a review of a massive inferno that engulfed an entire neighborhood. No, you won't find any damning assignments of blame heaped upon PG&E here -- but you do find a few interesting things.

  • Prior to the blowout, an electrical interruption cut power to the regulating valve for the ill-fated Line 132. As a result, the valve moved from "partially open" to "full open." Still, the pressure of gas flowing through the pipe apparently never exceeded the safety limit of 400 pounds per square inch -- though it got awfully close.

  • "The examination revealed that the ruptured segment was 27 feet 8 inches long at its longest length, and consisted of a pipe section and four smaller pipe pieces (pups) between 3 feet 8.5 inches and 3 feet 11 inches long (pups are numbered one through four from south to north)."

 The following laboratory work on the pipe has been completed:

  • Written documentation, photo documentation and visual inspection of the pipe.
  • Removal of the asphalt coating from outside of the three pipe segments in preparation for non-destructive examination work.
  • Radiography of the girth welds and select seams.
  • Microbiological testing of the pipe surface (samples currently being analyzed).
  • Ultrasonic wall thickness measurements.
  • Magnetic particle inspection of welds and seams.
  • 3-D laser scanning of the pipe pieces for a digital dimensional record of the evidence.
  • Measurement of the longitudinal and circumferential pup dimensions.
  • Removal of key fracture surfaces from the ruptured segment for further laboratory examination at the NTSB materials lab in Washington.

The following additional work is currently ongoing:

  • Precision cleaning of the fracture surfaces on the pieces cut from the ruptured pipe segment.
  • Hardness and microhardness testing.
  • Optical fractographic analysis and photodocumentation of the fracture surfaces on the pieces cut from the ruptured pipe segment.
  • Preliminary scanning electron microscopy of the fracture surfaces on the pieces cut from the ruptured pipe segment

Follow us on Twitter at @TheSnitchSF and @SFWeekly  

  • Pin It

Tags: , , ,

About The Author

Joe Eskenazi

Joe Eskenazi

Bio:
Joe Eskenazi was born in San Francisco, raised in the Bay Area, and attended U.C. Berkeley. He never left. "Your humble narrator" is a staff writer and columnist for SF Weekly, which he has written for since 2007. He resides in the Excelsior with his wife, 4.3 miles from his birthplace and 5,474 from hers... more

Comments

Subscribe to this thread:

Add a comment

Popular Stories

  1. Most Popular Stories
  2. Stories You Missed

Like us on Facebook

Slideshows

  • SuperHero Street Fair 2014

    From Batman to Superman to steampunk, people dressed up as their favorite superhero — or villain — for the annual SuperHero Street Fair held along Isails Creek, at the end of Indiana Street, on Saturday, Sept. 27. There was food, drinks, and lots of EDM music to dance to — check out all our photos form the event. Photography by Christopher Victorio.

  • @Large: Ai Weiwei on Alcatraz Exhibit
    Nathaniel Y. Downes brings back photographs from exhibit @Large: Ai Weiwei on Alcatraz. @Large runs through April 26, 2015.