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Oxygen cylinder inside firetruck explodes...
This may be pretty old stuff here but is everyone familiar why you don't put tape over the oxgen cylinder valving? This fire department did not follow this rule and when the firefighter was checking out the equipment, an explosion resulted. I'm hoping that someone out there has more specific information on this. But the photos tell the story.
Stay safe and train often!
Mike
Stay safe and train often!
Mike
Replies to This Discussion
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Permalink Reply by Fire Chick on
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wow
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Permalink Reply by Doug on
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I've also seen instances/pictures where scba bottles have exploded on the apparatus.
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Permalink Reply by Oldman on
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"excuse my ignorance, but why would you put tape over the valve?"
It is not ignorance as far as the question asked. It is the ignorance on the part of personnel and departments trying to save money by re-filling their own bottles. Fire and EMS services all across the country have or are still transfilling portable O2 cylinders from large H or J cylinders in a cascade style just like breathing air. This is a viable option when done correctly. A problem occurs because some departments are improperly and illegally filling cylinders. A few departments will fill in house, and because they don't know the laws or try to skirt them, will put tape over the valve outlet after filling to "keep contaminants" out of the valve. They are in fact adding contaminants. Now let me say emphatically, I am not accusing the department in the illustration above of anything improper or illegal.
Medical oxygen is a medication listed under the United States Pharmocopia, hence the U.S.P. by the word oxygen, and requiring a prescription from a licensed physician. As a medication, it is regulated by the Food and Drug Administration and the guidelines for transfilling are federally mandated, plus several states have enacted their own more stringent laws.
When air pack cylinders get low, we hook a hose to the cylinder, open a valve, and wallah... we have a filled cylinder. Because medical oxygen is a drug, legally, the one batch of drug cannot be comingled with another. The residual oxygen must be purged from the cylinder not just emptied, the cylinder must be evacuated by vacuum prior to the introduction of a new batch of medication. Quality assurance and purity testing are mandated for each batch as well as expiration dates and batch number placed on each cylinder. Now back to the problems. To properly transfill a compressed medical gas, transfilling equipment cost alone are in the $6000 - $15000 range. This is just for gas analyzers, valving and piping, connections etc. This doesn't include the cost of the portable cylinders, mandatory inspections by state health agencies and the FDA, then associated supply cost including items such as valve seals which are used instead of tape. Well enough of the class for today, (considering it is 36 hrs).
Getting back to the topic, they could have had tape around the valve, the adhesive is usually a petroleum based substance, (petroleum and oxygen don't play well together). But a much more common cause might be the regulator itself. There are many aluminum and aluminum alloy regulators which seem to have a higher incidence if this type than do brass or copper. Whatever the cause, these types of events are very violent and rapid.
Steps to avoid incidences such as this;
Only use cylinders which have been properly sealed, no tape.
Wear clean (latex or nitrile) gloves when changing cylinders. Eye protection is recommended.
Make sure only one gasket is in place.
Allow no foreign substances especially oil or greases to come in contact with regulators or valves
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Permalink Reply by Mike Schlags (Captain Busy) Retd on
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thanks for filling in the blanks here for me and others so we can all benefit from this topic...
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Permalink Reply by Trainer on
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Even though it’s illegal, I can think of 2 things; 1…anyone heard of plastic caps?? And I might suggest non-sparking tools. My local welding supplier has a picture of an o2 cylinder that exploded in the truck of a car….nothing left but 4 wheels and the floor.
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hydrocarbons + oxidizers = hypergolic reaction... (boom!)
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