CSB commends ICC on preventing future tragedies due to indoor purging
Published: 23 November, 2010
US Chemical Safety Board chairman Rafael Moure-Eraso has issued a statement regarding the International Code Council’s decision to prohibit indoor purging with an emergency amendment to the International Fuel Gas Code and the International Residential Code.
“On behalf of the U.S. Chemical Safety Board (CSB), 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). 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 of a catastrophic natural gas explosion that occurred at the ConAgra Slim Jim manufacturing facility in Garner, North Carolina, on 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, fuel gas piping systems in industrial, large commercial and large multifamily buildings may not be purged indoors. The provisions, had they been in effect at the time, would have required the gas pipe at ConAgra to be purged 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 just two months after the National Fire Protection Association announced identical changes to the National Fuel Gas Code, an action which the CSB also commends.”
The recent code changes previously approved by the NFPA and the emergency amendment now being voted on by the ICC membership do not affect high-pressure pipe cleaning operations using natural gas (known as “gas blows”), which the CSB concluded are inherently unsafe and should be discontinued in favor of safer alternatives using noncombustible gases. The explosion at Kleen Energy resulted from a natural gas blow that released about 400,000 standard cubic feet of gas into a congested area outside the power generation building.
