Prohibiting natural gas blows at power plants
Published: 20 October, 2010
US Chemical Safety Board (CSB) Member Mark Griffon has called on the American Society of Mechanical Engineers (ASME) to adopt a CSB recommendation calling for natural gas blows to be prohibited during power plant construction.
The recommendation was one of 18 urgent recommendations issued in June 2010 following a CSB investigation into a powerful natural gas explosion that killed six workers and injured dozens of others at the Kleen Energy plant in Middletown, Connecticut on February 7, 2010, which was under construction. Workers used hundreds of thousands of cubic feet of natural gas to clean debris from gas pipes used to fuel electricity-producing turbines. The gas accumulated in and around the buildings, was ignited by an unknown ignition source, and exploded.
Speaking to a meeting of ASME members in Phoenix who are considering changes to the ASME Code for Pressure Piping Systems, Mr. Griffon said, “The CSB believes that using natural gas or other flammable gases to clean fuel gas piping is inherently unsafe and should be prohibited.” He cited other accidents to show that explosions resulting from flammable gas blows have the potential of causing death, serious injuries, and costly property damage.
Mr. Griffon noted that the practice of using gas blows, or forcing large volumes of flammable gas through piping to clear out debris, was common in construction of electric generating facilities. The CSB investigation of Kleen energy, states: “From a fire and explosion perspective, releasing large volumes of natural gas in the vicinity of workers or ignition sources is inherently unsafe.”
Mr. Griffon noted the CSB investigation found ample alternatives to gas blows which are safer. These methods include blowing air or nitrogen through piping, or by “pigging,” in which a cleaning device is propelled through the pipe using air.
