[AT] OT - AFFF Fire Foam Unit

[charliehill]

Richard I'm not one of the firefighters but let me add some fuel to the fire 
(pun intended).  Nitrogen will not oxidize a fire but air, being mostly 
nitrogen but about 19% oxygen will.  Is that going to affect the fire 
protective characteristics of the foam?   Just wondering.

Charlie Hill
----- Original Message ----- 
From: "Richard Walker" <richardwalker at pobox.com>
To: <at at lists.antique-tractor.com>
Sent: Wednesday, July 29, 2009 7:29 PM
Subject: [AT] OT - AFFF Fire Foam Unit


> There used to be a few firefighters following ATIS, and I'm hoping
> for some help with an equipment question.
>
> I recently bought a skid-mounted fire control unit ridiculously cheap
> at a municipal surplus auction.  It consists of a Halon portion and
> an AFFF (Aqueous Film Forming Foams) portion using CAF (Compressed
> Air Foam) technology.  I am only interested in the AFFF portion,
> since we live in a high fire danger area backed up to the San Gabriel
> Mountains in Southern CA.  If a wildfire heads our way, foaming down
> the house and surrounding vegetation beforehand can increase our
> chances of coming through OK.
>
> The AFFF system is actuated from a large cylinder of high-pressure
> nitrogen.  A fixed regulator reduces this high pressure to a constant
> lower pressure.  I'm thinking about getting away from this dependency
> and converting to compressed air.  The air supply hoses leading to
> the pressurized foam solution tank are 200 PSI working pressure and
> 1/2" in size.  So based on this, my wild guess is that the needed
> working pressure might be around 100 PSI and the air volume from 20
> to 50 CFM, assuming the hoses were roughly sized to the air requirements.
>
> Would anyone with experience have a more precise answer as to
> pressure and air volume?
>
> Whatever, that will take one BIG compressor.
>
> Photo of the unit:
>
> http://www.walkerpublications.com/tractors/FireFoam02.jpg
>
> Thanks.
>
>
> Richard
>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at