Aug 05, 2010-The Chemical Safety Board has now recommended OSHA (Occupational Safety and Health Administration) to ban purging of pipelines with natural gas, that can cause explosions. This should have been done a long time back, but it was only after the Kleen Energy explosion that things started moving in this direction.
This is rather surprising for evrybody in the chemicals, petrochemicals and oil industries who have operated boilers, fired heaters, etc are aware that before starting any burner, some purging is to be done with air, to drive away residual gas in the burning chamber to prevent explosions and back firing. However it is surprining that in many natural gas processing facilities instead of using Nitrogen or compressed air for purging, they use the natural gas itself. This in itself may not be entirely unsafe IF and this is a BIG IF that the surroundings are free of ignition sources of any kind and the gas can quickly dilute below its % LEL (lower explosive limit). However in the Kleen energy kind of situation where there was large scale welding and cutting going on, with plenty of sparks flying around, it is surprising that the regular venting of natural gas purging resulted in just one explosion…theoretically it should have resulted in many!
There is an urgent need for people to understand the principles of explosion protection, classified areas, hazardous area classification, gas monitoring and other such concepts to prevent Kleen energy like incidents.
Anyways, here’s what the CSB now says (reproduced from their website)
Statement of CSB Chairperson Dr. Rafael Moure-Eraso Urges OSHA to Adopt CSB Recommendation Prohibiting Flammable Gas Blows During Pipe Cleaning Operations
On June 28, 2010, at a public meeting in Portland, Connecticut, the Chemical Safety Board voted to issue 18 urgent recommendations to various recipients, including OSHA, aimed at halting the dangerous practice of releasing large quantities of flammable gas in the presence of workers and ignition sources during cleaning operations.
Six workers were killed and there were numerous injuries on February 7, 2010, at the Kleen Energy power plant under construction in Middletown, Connecticut.
A recommendation to OSHA called for, among other things, the promulgation of regulations to prohibit the release of flammable gas to the atmosphere for the purpose of cleaning fuel gas piping.
Today, OSHA announced citations and proposed fines against construction companies and contractors at the Kleen Energy power plant construction site and announced a plan to notify natural gas power plant operators of the dangers of natural gas blows.
I was pleased that during his news conference, Dr. David Michaels, assistant secretary of labor for OSHA, stated his agency is studying the CSB recommendation to prohibit flammable gas releases during cleaning operations, and that OSHA agrees with the CSB that this problem must be addressed immediately.
Dr. Michaels stated that OSHA likely does not have the authority to prohibit the use of flammable gases during pipe cleaning operations, and that promulgating such a regulation would take years.
The CSB believes that OSHA does have adequate authority to take this action and to start the standard setting process at any time.
The CSB found that the practice of gas blows is inherently unsafe. In its investigation of the Kleen Energy accident, the CSB found that several safe alternatives to pipe cleaning are available to the industry are already in use, such as compressed air, nitrogen and the use of a solid cleaning device propelled by compressed air that is referred to as a pig. Furthermore, the CSB found companies have already begun to ban the practice. And at least one leading manufacturer of natural gas electric turbines, General Electric, has informed its customers it will not support the practice of gas blows to clear out pipes leading to the turbines. A GE official discussed this during the CSB public meeting held in June in Connecticut.