Indoor Purging Out After NC Blast

Thursday, November 4, 2010 @ 12:11 AM gHale

Chemical Safety Board (CSB) Chairman Rafael Moure-Eraso gave a thumbs up to the International Code Council for its emergency amendment to prohibit indoor purging.
The amendment to the International Fuel Gas Code and the International Residential Code comes after the CSB recommendations after the June 2009 fatal natural gas blast at the ConAgra Slim Jim Plant in North Carolina.
“I would like to take this opportunity to commend the International Code Council’s (ICC) Board and membership for voting to approve an emergency amendment to the fuel gas purging requirements of the International Fuel Gas Code (IFGC) and the International Residential Code (IRC),” Moure-Eraso said. “The CSB believes these new requirements are urgently needed to prevent future tragedies resulting from unsafe purging practices at industrial, commercial and public facilities.”
The CSB conducted an investigation into the explosion at the ConAgra Slim Jim manufacturing facility in Garner, NC, June 9, 2009.
“That tragic and preventable accident took four lives, injured 67 others, and led to a decision to close the plant with the loss of hundreds of jobs in the region. The accident occurred during an operation to purge, or clear, air from a new steel gas-supply pipe that was connected to a newly installed industrial water heater.
“Due to difficulties in lighting the water heater, the purging operation was continued for an unusually long time, eventually causing gas inside the building to accumulate to a concentration above its lower explosive limit. The gas exploded after contacting an ignition source, causing extensive sections of the large facility to collapse. The explosion also damaged piping from the plant’s ammonia-based refrigeration system, causing approximately 18,000 pounds of anhydrous ammonia to be released to the environment.”
Under the new code requirements it is not possible to purge indoors fuel gas piping systems in industrial, large commercial and large multifamily buildings. The provisions, had they been in effect at the time, would have required the gas pipe at ConAgra to purge outdoors, away from personnel and ignition sources. They also require that purging activities be monitored using appropriate combustible gas detectors to prevent significant releases of flammable fuel gases.
ICC’s Emergency Amendment comes two months after the National Fire Protection Association unveiled identical changes to the National Fuel Gas Code.

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