Report

 

Subject:                     Kleen Energy Plant  - Further Information

Date of Email report:   Sat 20/02/2010

Report Detail:

The following was sent to me by a person who wishes to be nameless - As Trevor Kletz has said on may times we fail to learn from history....

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The February 7, 2010, explosion at the Kleen Energy plant under construction in Middletown, CT caused extensive property damage, delays in project completion as well as the tragic loss of life and injuries to at least twelve people.  Understandably, this event has raised concerns among our clients about plant safety.  At the time of the accident, the plant was 95% complete and due to be finished this summer.  The plant was conducting a "blow down", which is a clearing/purging of the natural gas lines, when the explosion occurred.  Investigation into the loss is only beginning.   However, a number of accidents have occurred involving natural gas explosions, including several in the power generation arena.   These losses share at least one common characteristic: they resulted from gas fuel leaks / releases during periods when the damaged plants were idle or being made ready to startup or restart.  Scenarios and details varied widely, depending on subject plant configuration & layout.   Below are some findings from these past losses concerning procedures that plants are urged to consider in their effort to prevent future accidents involving natural gas explosions.


Purging Gas lines safely
Following an accident at a SlimJim plant in North Carolina  in June 2009, the US Chemical Safety Board (CSB) released a safety bulletin [attached] regarding dangers of purging gas piping, I note this given the fact that the Kleen Energy  accident earlier this week also involved purging of gas lines. The findings from the CSB investigation identified key lessons for the safe purging of fuel gas, including

  • Purging flammable gases to a safe outdoor location, rather than indoors.   

If this is not possible, the CSB suggests:  

  • Removing nonessential personnel,  
  • Eliminating ignition sources, and  
  • Ventilating the space so that the atmosphere is substantially below the lower explosion limit of the gas/air mix.   
  • Utilizing combustible gas detectors to monitor gas concentrations during the purging operations.  

While the CSB findings focus on problems with indoor venting, outdoor gas leaks outdoors can also ignite, especially in congested areas where leaking gases might accumulate.  This week, Dr. Trevor Kletz sent me an excerpt from his book "What Went Wrong" which is based on his experience with another natural gas explosion where natural gas discharged inside of a building.  He asked that I share this excerpt with those reading this, and I am happy to do so, as I believe you may find it instructive.  Dr. Kletz worked as a process engineer for ICI in the UK before dedicating most of his career to preventing such losses from recurring.  Dr. Kletz is also the father of HAZOP [“Hazard and Operability Studies”].  The excerpt is an attachment to this E-mail.


Following Procedures / Contractor Safety
Whenever construction-related accidents occur, root cause analysis focuses on procedural issues for all facets of the project.  The investigation includes the safety performance of those involved on the project, contractors’ similar project experience and its hazards, etc.  Especially important are:

  • Steps taken to ensure safe purging of equipment, including making sure ignition sources are removed (no cutting and welding activity, removing portable space heaters, pilots off on HRSG duct burners, etc.);
  • Demonstration that frequent combustible gas detection monitoring is performed throughout the area;
  • Ensuring that simple isolation precautions such as blanking off lines and installing double block values are followed.  Losses associated with valve/gasket failures often can be prevented by following proper procedures.
  • Procedures to ensure that workers, particularly those involved in hazardous activities, are not only fully qualified to perform the tasks at hand, but not seriously overworked, since fatigue [and a related cause – unrealistic productivity demands] is a leading factor in human error.

Additional Documentation:

KleenEnergyPictures

KleenEnergyNewsArticles

WhatWentWrongArticle

CSBSafetyBulletinPurgingGasPiping2009