A standard for preventing fires and explosions during cleaning and purging of flammable gas piping systems has been released by the National Fire Protection Association (NFPA), Quincy, Mass.

NFPA 56 prohibits the use of flammable gas as a cleaning agent for cleaning the interior of pipes. The 2012 Edition, a provisional standard, was developed in the wake of the 2010 explosion at the under-construction Kleen Energy Power Plant in Middletown, Conn., that killed six workers and injured nearly 50 others, and a subsequent investigation by the U.S. Chemical Safety Board (CSB). As part of the commissioning process for this facility, highly pressurized flammable gas (natural gas) was used to clean debris from the piping and then was discharged without controls into the atmosphere, causing the explosion. As a result of their investigation, CSB issued recommendations to various parties, including the NFPA.

NFPA acted quickly, forming a new technical committee and charging it with the responsibility to develop a new standard. NFPA 56 addresses not only the cleaning practice known as “gas blows” but also a range of gas process activities such as pipe cleaning, repair, replacement and removal procedures conducted at power plants and at industrial, institutional and commercial facilities and applications.

“Our ability to bring together the right people at the right time and to facilitate a consensus process in very short order resulted in a standard that will save lives and prevent a tragedy like the one in Connecticut from happening in the future,” says James M. Shannon, NFPA president.

Among the requirements of NFPA 56 (PS) are the following:
  • Prohibits use of flammable gas for internal cleaning of piping systems.

  • Covers activities including cleaning new or repaired piping systems, placing piping systems into service, and removing piping systems from service.

  • Requires development of written procedures and a safety validation of procedures by competent persons.

  • Provides example of purge procedure based on requirements in the standard.
“Nineteen months ago, the Middletown community was witness to an awful tragedy at the Kleen Energy plant, when a then-routine gas blow procedure went terribly wrong," said Congresswoman Rosa L. DeLauro, D-Conn., at the September press conference announcing the standard. "The investigation into what happened that day resulted in this new worker protection standard - the first of its kind to address this dangerous procedure. I thank the NFPA and CSB for steadfastly moving to develop this critical response which will help to save lives across the country. We owe it to the men who perished that terrible day to make the tragedy in Middletown the very last of its kind.”

More information on NFPA 56 can be found at www.nfpa.org/56.

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