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Debate over fire classes
Ok, so I'm a scout, and one of my scout friends decides to quiz people on fire classes and substances to put them out. So, all goes well until we get to class D- metals. He tells me that one should use CO to extinguish this (after I said dry powder, such as graphite powder). And the fifth class, he says is class E, nuclear fires, though I've heard all over town that the fifth class is Class K- Kitchen fires, caused by cooking oils and fats (a sub- category of B).
My question is... Was I right? I've gone to wikipedia, downloaded a pdf packet from a fire department explainging the types of fire, looked in the manuals and the merit badge booklets. And they do definitely say "dry powder" under Class D. And the ones that do mention a fifth class (the pamphlet and wikipedia) say the fifth class is class K.
Yes, I go to great lengths to prove I'm right. You have to admire the dedication!
My question is... Was I right? I've gone to wikipedia, downloaded a pdf packet from a fire department explainging the types of fire, looked in the manuals and the merit badge booklets. And they do definitely say "dry powder" under Class D. And the ones that do mention a fifth class (the pamphlet and wikipedia) say the fifth class is class K.
Yes, I go to great lengths to prove I'm right. You have to admire the dedication!
Replies to This Discussion
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Permalink Reply by John Crabbe on
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So, all goes well until we get to class D- metals. He tells me that one should use CO to extinguish this (after I said dry powder, such as graphite powder).
I believe you meant to say CO2 (carbon dioxide) vs CO ( carbon monoxide) only CO2 is used as an extinguishing agent.
However, CO2 is NOT typically used for burning metals, it could be used, but is not the primary agent. The primary agent is a Class D extinguisher, typically yellow in color and represented by a star symbol. Sand can also be used as well, but is not a primary agent.
And the fifth class, he says is class E, nuclear fires, though I've heard all over town that the fifth class is Class K- Kitchen fires, caused by cooking oils and fats (a sub- category of B).
Can't say I've ever heard of nuclear fires, if you have a fire in a nuclear place, the primary issue is radiatio which may be present despite what is actually burning. This means there is not a seperate class of "nuclear" fires, as Japan has recently shown, with the reactors, the agent used to cool was water.
However, there IS a Class K extinguishers for cooking oil fires and is used as you stated.
All in all though, there can be an issue of being right and proving you are right. My suggestion would be to not make a big deal out of things, but just show the facts.
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Permalink Reply by lutan1 on
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Good luck putting that baby out!!!!!
Seriously though, Capt Busy put up a good discussion recently about the classes of fire and how they differ around the world- well worth the research and read....
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Permalink Reply by Bob Callahan on
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There are 5 classes of fire.
You are correct. Class K, which is commercial sizes vats of cooking oils, such as those found in restaraunts, is the fifth class.
There is no class of fires covering radiological materials.
As far as Class D, dry powders designated for Class D fires is one way of extinguishing the fire. Other methods include dry sand or dirt, or coupuious amounts of water, preferably in an exterior fire situation.
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Permalink Reply by Katie on
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The prompt given was "name the five classes of fire and what you use to put them out"; it was not stated that ALL extinguishing agents should be provided in the answer (or "urine" would've definitely been in class A...). The thing is, he told me I was wrong on all this (that dry powder was wrong, and "CO" was the best way to go in a class D, and nuclear fires, etc.). There are prizes involved in this, and my boyfriend is very stubborn. So... I reserve the right to make a big deal (yay, prizes!)
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Permalink Reply by Devan Mills on
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CO2 is used as a smothering agent on fires, and i do not believe that any fire extinguisher is going to be sufficient enough to extinguish a nuclear fire. the fifth class is class k combustible cooking
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Permalink Reply by Pararescue on
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Ask him about Purple K.... My Dept carries Purple K extinguishers 2, other than that, the Buffalo Niagara Airport has some.
http://en.wikipedia.org/wiki/Purple-K
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Permalink Reply by Moose on
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Class "K" is the fifth class. It is called "K" because of the chemical in the extinguisher called "Karbaloy". This chemical will make a chemical reaction with the commercial cooking oils and grease, and turn it into a fire resistive soap. So, with the water it is mixed in, both the karbaloy and water mist serve to cool the fire down, and make a fire resisitive soap barrier to keep it from spreading should it flare up again after initial extinguishment. I used to be a technician that installed and maintained kitchen hood fire suppression systems and extinguishers, I also servced them and re-charged them at the shop and got to fill and charge quite a few of these class "K" type extinguishers.
For flammable metals it has to have absolutely NO MOISTURE in the extinguishing agent, so even if you use sand, but it has some moisture in it, it could make it flare up still. So if you use sand it has to be dry stuff kept in garages or bins, like the play sand in 50 pound bags. Dry-chem works also.
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Permalink Reply by Daniel J. Graham on
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A- Ordinary Combustibles (Wood, paper, etc.)
B- Flammable Liquids
C- Electrical
D- Flammable Metal
K- Industrial Kitchen/Grease
Sounds like someone needs to look at the material a little bit longer before trying to present it to others. Be smart and learn from his mistake.
Keep your head up sweetie - you're right on this one.
And if you happen to find one of those 'CO extinguishers', let me know. I have a few ideas for it. :-P
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Permalink Reply by Ben Waller on
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Daniel's points are right on target.
A couple of additional points on Class D fires:
One of the best extinguishing agents for Class D fires is graphite powder. It's messy but it works. Class D fires must be smothered. Class D metals are water-reactive, so using water-based agents will typically increase the fire, at least until the fuel is consumed.
Carbon dioxide (CO2) may temporarily reduce combustion froma Class D fire, but it won't usually extinguish those fires. Class D fires are extremely hot. CO2 is a very short-acting agent. When the CO2 dissapates, the Class D metal will usually be hot enough to re-ignite, so all you did was waste the CO2 extinguisher.
There used to be a graphite-based Class D extinguisher called "MetalX" that was good for Class D fires. I don't know if they're still made, but it's worth looking them up.
Good luck.
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Apparently a special sodium chloride-based Class D extinguisher is becoming more popular.
MetalX extinguishers are still available from Ansul.
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