Was poor area classification to blame for explosion at Veolia ES Technical Solutions Hazardous Waste Facility?
July 21, 2010, Washington DC- The US Chemical Safety Board (CSB) has come out with its investigation report on the 2009 explosion and fire at the Veolia ES Technical Solutions L.L.C. facility in West Carrollton, Ohio. It calls on the waste management industry the industry to improve safety standards covering
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hazardous waste processing, handling, and storage facilities. The Board also recommended that fire protection codes be revised to require companies to determine safe distances between occupied buildings and potentially hazardous areas.
This is because in the accident, flammable and explosive vapors of a solvent Tetrahydrafuran (THF) leaked and traveled some distance away from the processing area to an area that apparently was not classified as a hazardous area. These flammable vapors found anignition source and exploded, devastating the facility and the neighborhood too.
Read the entire report here (given below).
The accident occurred on May 4, 2009, when flammable vapor was released from a waste recycling process, ignited, and violently exploded. The blast seriously injured two workers and damaged 20 nearby residences and five businesses. CSB investigators found that the north wall of the lab and operations building – where the victims were injured – was less than 30 feet from the waste recycling processing area where the flammable vapor was released.
CSB Chairman Rafael Moure-Eraso said, “This accident should not have happened. Our report notes that OSHA cited the company for inadequate attention to process safety management practices in the handling of flammable liquids. But in case of an accident, I believe it is absolutely critical that buildings at chemical facilities be sited safe distances from process equipment to maximize the safety of workers. We are making recommendations that would help ensure that operating areas with occupied buildings such as control rooms be sufficiently separated from process areas containing flammable liquids and gases that have the potential to explode.”
The Board issued a recommendation to the National Fire Protection Association (NFPA), which develops codes and standards for industry, urging NFPA to require companies to perform engineering analyses to determine safe separation distances between buildings occupied by administrative and other personnel not essential to process operations, and buildings housing the potentially hazardous process equipment.
The Board also revised a previous recommendation to the Environmental Technology Council, a hazardous waste industry trade group, to petition the NFPA to develop a standard specific to hazardous waste treatment, storage and disposal facilities. This would include guidance on reducing the likelihood of fires, explosions, and releases of hazardous waste.
Dr. Moure noted, “The Environmental Technology Council did not respond adequately to our 2007 recommendation, which we issued following an explosion and massive fire at the Environmental Quality hazardous waste facility in Apex, North Carolina, to work for more stringent standards in the hazardous waste industry. I strongly urge the industry to act now. These facilities, by their nature, contain wide varieties of flammable and toxic materials that can cause significant injury to workers and threaten the well being of nearby communities. Facility owners and operators need stricter technical requirements to improve the safety of life and property.”
The report notes that after a normal run of the tetrahydrafuran (THF) solvent recovery process at the Veolia facility, the unit operator began a routine shutdown. Completing the process required blowing nitrogen back through the circulation piping to clean it, prior to closing valves.
CSB lead investigator Johnnie Banks said, “At the time of the shutdown, witnesses reported hearing the sound of a sudden, loud vapor release and smelling a very strong odor of THF solvent which knocked several employees to their knees. It was a matter of just a couple of minutes until the highly flammable vapor ignited.”
The vapor drifted to the laboratory and operations building and found an ignition source inside the building. A worker in the control room reported being enveloped in a fireball that went through the building. The first explosion knocked over a bank of lockers, severely injuring an employee and pinning him underneath.
Because of the extensive fire damage, the CSB was unable to conclusively determine the exact initiating event for the vapor release, concluding one of two possible scenarios likely occurred. In the first scenario, air may have been drawn into a tank containing THF residue and peroxides, causing increased pressure in the tank and forcing flammable vapor from the tank to escape through a manway cover or a vacuum breaker.
In the second possible scenario, CSB investigators believe a line hose, intended to send pressurized nitrogen into a different tank, may have instead been connected to a tank containing unprocessed, flammable liquid. When the nitrogen was applied, it forced flammable vapor out through the tank vent. In either scenario, the vapor drifted to the operations building and ignited, causing the injuries.
In addition to issuing recommendations to NFPA and the hazardous waste industry, the Board also issued recommendations to Veolia, which is rebuilding the plant. The CSB called on the company to restrict occupancy in buildings in close proximity to the operating plant to personnel trained in the safe operation and orderly shutdown of the plant. The Board also called on the Center for Chemical Process Safety, a division of the American Institute of Chemical Engineers, to revise control room siting guidelines to address the characteristics of all Class 1B flammable liquids.
A Practical Guide to Hazardous Area Classification
Miami-FL, Feb 16, 2010- If you are looking for a practical guide to Hazardous Area Classification, then look no further.There is a new ebook in a flip page format (just looks like a real book), that has all the essential information that you need to know about area classification.
As you must have known by now, area classification is very important to industries and facilities that handle, store or otherwise process hazardous (flammable liquids and vapors). Also, if a facility is handling large amounts of dusts (like grain dust or coal dust), then it needs to be classified also as a hazardous area, with the code that is applicable to dusts. This classification can be sometimes very intimidating and even confusing, what with the plethora of varying standards and codes. The IEC system and the North American (NEC) systems are covered for vapors, gases, as well as dusts. Actual real life area classification drawings are provided, that really area a help, as compared to the same stale figures that are repeated in all publications.
This guide is a fast start to your area classification exercise. It is always a good safety practice to review the hazardous area classification of an industrial facility, every few years, due to the changes, modifications in equipment or new layouts that have now become a permanent development in most plants. If the area classification was done ages ago, then it is better to review it once again, to confirm that the old classification still holds, or to change it if necessary.
This guide provides a very concise overview and even provides a step by step procedure that was followed while doing an area classification. Definitely a must have book for understanding area classification.
Also, since a trial version is available, you can download and see for yourself immediately. Click here to get it.
Note that you will require a DNL reader to view it (similar to Adobe reader but much better), you can get it from here.
Why is Acetylene part of Group IIC of IEC (Group A of NEC)
Ever wonder why Acetylene is classified under Group IIC of the IEC’s explosive material classification system (equivalent to Group A of the NEC material classification)? Why is it classified as much more explosive as compared to say, Methane?
Rather than launch into the theory of explosivity and other such things, wouldn’t it be nice to watch how a 0.5 gms qty of Acetylene behaves when ignited? Watch the video below.
More information on the reasons of area classification can be understood by downloading the ebook on hazardous area classification here.
How to classify hazardous areas?
This is the question that many people ask themselves. There are so many standards and practices, so different from each other. You have the Class, Division & Group classification in North America and the Zone and Group system in Europe, Asia and Australia. The NEC also talks about Zones in Article 505 and there is the IEC-Ex harmonization scheme. To make matters more interesting, we have ATEX in the EU.This all adds to the confusion.
On the other hand, all of us agree that a lack of understanding of how to carry out area classification, can result in a disaster at worst, or at best, a huge lifecycle cost. How? If a poor area classification scheme results in a hazardous area marked as non-hazardous, then that is an invitation to a disaster. Similarly, overzealous area classification can result in large swathes of your plant marked as hazardous, when in reality they need not be. If a typical life of a process plant is about 30 years then you have 30 years of increased maintenance and operations costs, that will fly under the radar of most managers. So it will bleed your plant dry without anybody noticing it. Great, isn’t it?
So here’s an answer. Get your copy of the new Practical Guide to Hazardous Area Classification, recently released by Abhisam Software. It costs just $27, but is worth many more times in the value that it offers. In addition to a compilation of all the well known standards and systems of classification, it has practical examples from working process plants including drawings and photos, to give you a unique perspective on Area Classification. And if you do not want to spend even the $27 on it, you can get it free, if you buy the Hazardous Area Instrumentation course from them, but I think it’s only for a limited time.
You can drop your feedback/review of this book in the comments section.
If you would like to know more about how proper hazardous area classification is important, you can refer to a blog post on this blog earlier here.
Anniversary of the Imperial Sugar factory dust explosion-CSB releases a safety video message
On Feb 4th, 2009, on the first anniversary of the dust explosion that took place at the Imperial Sugar factory, the US Chemical Safety Board released a video message. In the video (see below) the CSB chairman John Bresland asks federal regulators and businesses to increase efforts at preventing combustible dust fires and explosions.
For those who remember, the incident was one of the worst dust explosions ever, with 14 fatalities.
Just a few days ago, a coal dust explosion rocked the Oak Creek We Energies power plant. It took place in a silo and injured 6 contract workers. Fortunately there were no fatalities. One of the workers described a loud explosion and a ball of fire came rolling down at them inside the 65 foot high silo, making them scramble to safety, reports the Journal Sentinel of Milwaukee.
What is the cause of so many dust explosions? The CSB completed a major study of such combustible dust hazards and has urged the Occupational Safety and Health Administration (OSHA) to develop a comprehensive regulatory standard designed to prevent dust explosions. OSHA has not issued a standard but has developed a program to increase enforcement of existing regulatory provisions.
One of the causes of these dust explosions is a possible electrical ignition source, due to using non-dust ignitionproof motors, switches and other non-protected electrical and instrument equipment in hazardous areas. Most industry people think of hazardous areas as those that contain flammable solvents and vapors, but fail to remember that hazardous areas also cover dust prone areas. These include grain silos, coal processing and storage plants and yes, even sugar factories. (Under the North American codes, these are classified as Class II hazardous areas and under the IEC codes, these areas are classified as Zone 21 and Zone 22)
Once a dust explosion takes place, it causes severe damage and the only way to safeguard lives and machinery, is by prevention. Use of explosion protected equipment that is certified for use in dust hazardous areas is a must.
(You can learn more about hazardous areas and dust explosion protection in Abhisam Software’s e-learning program on Hazardous Area Instrumentation).
Comments are welcome, as usual.
