CSB Urges Gas Utilities to Avoid 'Gas Blows'
Investigations Supervisor Don Holmstrom briefed reporters today about the investigation so far into the Feb. 7 Kleen Energy explosion, which has claimed six lives.
About 400,000 standard cubic feet of natural gas was intentionally vented at the nearly completed Kleen Energy plant in Middletown, Conn., during the 10 minutes leading up to the Feb. 7 explosion that caused severe damage and killed six people, to date, U.S. Chemical Safety and Hazard Investigations Board Investigations Supervisor Don Holmstrom, J.D., told reporters today. He briefed them about the investigation so far into the explosion and urged the gas utility industry not to conduct such "gas blows," in which highly pressurized gas is used to move debris from inside new piping and then vented into the atmosphere. The gas used in the Middletown plant's gas blow that morning was at a pressure of approximately 650 pounds per square inch, and it then was vented through open pipe ends located less than 20 feet off the ground. The vents were adjacent to the main power generation building.
"Our focus today is on the safety message of the inherent danger of releasing flammable gases in close proximity to workers and ignition sources," Holmstrom said. He said the board's team of 10 investigators is not focused in identifying the ignition source, but numerous sources were present at the time of the blast.
He said "gas blows" are a common practice as new or modified gas pipes are being commissioned at gas power plants, according to industry personnel, and a major focus of the investigation is to determine whether codes, regulations, and good practices address them. No specific codes have been identified so far, he said.
"This gas was released into a congested area next to the power block building," Holmstrom said in a statement CSB posted today. "This congested area likely slowed the dispersion of the gas. The gas built up above the lower explosive limit of approximately 4 percent in air and was ignited by an undetermined ignition source."
CSB adopted urgent recommendations on Feb. 4 calling for national fuel gas codes to be changed to improve safety when gas pipes are being purged of air during maintenance or installation of new piping. Those recommendations came from the board's probe of the June 9, 2009, natural gas explosion at the ConAgra Slim Jim plant in Garner, N.C.
The Safety Information Resource Center of the American Gas Association, which represents 195 local gas utilities that serve 64 million customers, offers safety alerts and articles from American Gas Magazine. The association's next executive safety leadership summit is scheduled for September 2010 in Boston.