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leland #171926 12/08/07 11:33 PM
Joined: Jan 2005
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Please explain the "C" symbol on CO2 extinguishers. That's supposed to mean "OK for electrical fires"

leland #171928 12/08/07 11:46 PM
Joined: May 2005
Posts: 247
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Everything I can find indicates that CO2 is non-conductive, and recomended for electrical fires at all voltage levels. It is stored in liquid form, but discharged in gaseous form.

ABC indicates the type of fires that the extinguisher can be used to extinguish, not the specific agent.

C indicates that the agent is non-conductive, and suitable for electrical fires.

CO2 is rated BC, for flamable liquids and electrical fires.

You may be thinking of class K extinguishers, which are specially formulated for kitchen grease fires, but the agent may be conductive.

techie #171929 12/08/07 11:52 PM
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Here's a link, for a UL listed CO2 extinguisher. Please note it has a "C" rating: http://www.marylandfire.com/miva/me...mp;Product_Code=322&Category_Code=FE

renosteinke #171935 12/09/07 12:31 AM
Joined: Aug 2007
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OK--OK--OK--- Ouch, I may be wrong. You guys have put out very strong points.
My Training from some pros' have told me this, against the obviouse. Again with the hear say.
I will do some more research. Perhaps the fact of the static conductivity I have become confused.

UNCLE!!! Leme up!!!.
Never afraid to admit my wrong. But an industry can't be wrong.

leland #171936 12/09/07 02:34 AM
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To do much more than out out an electrical fire CO2 has to be huge. Something you roll, not something you carry. If you have a significant fuel load like A and B fires you pretty much have to flood the flame with CO2 and smother the fire, along with the normal cooling you get with CO2.
Back in the real olden days we had computer rooms with CO2 flooding systems (AEC in Germantown had one) but I was never sure if this was fire protection or intruder control. wink


Greg Fretwell
gfretwell #171937 12/09/07 04:01 AM
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The Navy taught us to keep the CO2 extinguisher on the ground to avoid it generating a spark of static electricity. Not good if you've almost got the flamable liquid/gas fire out....

techie #171938 12/09/07 07:04 AM
Joined: Jun 2004
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Originally Posted by techie

You may be thinking of class K extinguishers, which are specially formulated for kitchen grease fires, but the agent may be conductive.


Also known as a class "F" extinguisher in Australia. Class "F" is called wet chemical. The extinguisher is red with a wheat colour band across the centre of the body ( used to be all wheat coloured)

32VAC #171946 12/09/07 10:29 AM
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In earlier posts it was touched on about the use of a extinguisher, remember the saying "PASS"? P,Pull the pin, A, Aim at the base of the fire, S, Squeeze the trigger, S, Sweep at the base of the fire.

leland #171956 12/09/07 04:13 PM
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leland,
If what you say is true, why do all CO2 extinguishers have a Class C rating? The following is from this site.
Quote
Class C fires involve electrical equipment, such as appliances, wiring, circuit breakers and outlets. Never use water to extinguish class C fires - the risk of electrical shock is far too great! Class C extinguishers do not have a numerical rating. The C classification means the extinguishing agent is non-conductive.

Don


Don(resqcapt19)
resqcapt19 #171958 12/09/07 04:44 PM
Joined: Feb 2003
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I was in our computer room at work for a few hours this morning and I noticed that all the Co2 extinguishers have been replaced with misting water extinguishers (in addition to the FM100 suppression and dry pipe sprinklers). If we ever have a fire it appears we will either gas and flood the room to put it out depending on which trips first.

This extinguishers have a special deionized water charge and are rated class AC because of the misting head. The mist keeps any electrical current from coming back to the user.

These are the units we now have http://www.amerex-fire.com/Literature/wmist.pdf

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