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Old 12 August 2006, 11:36   #21
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Quote:
Originally Posted by jwalker
I think that is true for Co2 but at close quarters, as might be the case in a rib, the cooling effect is substantial and if you release Co2 into a small fire there is often ice on the surface where the flames have been extinguished. Whilst displacing the air (hence oxygen) is a benefit, if you do a bit of research on the Halon replacement gasses, I think you'll find they do absorb heat. If they just displaced the oxygen, it wouldn't matter which inert gas was used.

I would guess that they initially remove heat to below a point of ignition then they prevent reignition by hanging around excluding the oxygen. As I said, just guessing.
No idea on Halon but I am pretty sure the cooling effect of CO2 is down to basic physics. You are rapidly boiling a pressurised liquid into a gas and therefore that absorbs heat - a bit like the principle an air con system works on I suppose.

I use CO2 bottles for my beer brewing at home and if you trigger the nozzle with your fingers you can end up frozen to it... the cooling effect is huge.
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Old 12 August 2006, 21:48   #22
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AFFF Trash

The replacement for Halon is AFFF. But from my experience in motor sport AFFF does not even come close to Halon. For me it has to be Halon all the time.
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Old 12 August 2006, 23:00   #23
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Sparkey, maybe in motor sport the halon has been replaced by AFF foam but that is not what is commonly known as halon replacement. There are various gases and, I believe, some fluids which evaporate rapidly into a gas, and this group is the halon replacement we are referring to.
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