A new standard devised by the National Fire Protection Association (NFPA) in response to the February 2010 Kleen Energy Systems power plant explosion prohibits the use of flammable gas as a cleaning agent for cleaning the interior of pipes—the practice thought to have caused the blast that killed six workers in Middletown, Conn., and injured nearly 50 others.
The standard is not mandatory—but it could be used by state governments and federal agencies like OSHA to develop rules banning the use of flammable gas in pipe cleaning. This year, Connecticut became the first state to make the procedure illegal. No other states have so far followed suit.
Unveiling the new standard at a press conference at Middletown City Hall, Middletown, on Tuesday, NFPA, along with U.S. Rep. Rosa L. DeLauro (D-Conn.), Rep. Joe Courtney (D-Conn.) CSB Chairman Rafael Moure-Eraso, and other politicians, urged state and federal regulators to adopt the new standard.
The international nonprofit organization’s release of NFPA 56 (PS), Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, 2012 Edition, was developed as a result of the explosion of the natural gas power plant that had been under construction and after an investigation by the Chemical Safety Board (CSB), the group said.
The CSB found that as part of the commissioning process for the facility, highly pressurized natural gas had been used to clean debris from piping. The flammable gas was then discharged without controls into the atmosphere, causing the explosion.
The federal investigative agency urged various parties, including NFPA and the Occupational Safety and Health Administration (OSHA), to formulate standards to ban the gas blow procedure. NFPA said it acted “promptly,” forming a new technical committee and charging it with the responsibility to develop a new standard.
In addition to the CSB urgent recommendation to not allow the use of flammable gas as a cleaning agent for interior pipes, NFPA 56 (PS) expands on the CSB recommendations by including cleaning and purging of all flammable gas piping systems at any inlet pressure for electric-generating plants, industrial, commercial and institutional applications.
The new standard also covers activities including cleaning new or repaired piping systems, placing piping systems into service, and removing piping systems from service. It requires development of written procedures and a safety validation of procedures by competent persons, and it provides examples of purge procedures based on requirements in the standard.
For more on best practices on natural gas line cleaning, see POWER’s September 2011 issue.
Sources: POWERnews, NFPA, CSB