Date:         Sat, 11 Nov 2000 03:49:52 -0500
Reply-To:     Stephen Steele <steeles@HORIZONVIEW.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Stephen Steele <steeles@HORIZONVIEW.NET>
Subject:      Re: types of fire extinguishing agents: (long, sorry)
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Bill Davidson wrote:
> Anybody have experience or know anything about this Aqueous Foam stuff?
> Clean up?
>
 Bill:
AFFF (called A triple F): aqueous film forming foam. First used in military
aircraft fire fighting applications in the late sixties, particularly on
aircraft carriers. It is a detergent-based liquid that forms a very thin,
effective, smothering film on most surfaces which prevents air from allowing
a re-ignition of the combustible material. Since it tends to float on other
liquids it is commonly called "light water" and usually (in the several
fires we fought onboard my ship) didn't really foam as much as "coat".  In
most military applications it was combined with PKP (purple K...
potassium,sodium bicarb...co2 ...baking powder...chemists?). The two systems
were separately
applied with a twin hoseline, first with the PKP in a powder from  one
nozzle to knock down the flames and then with the AFFF from the second
nozzle to coat the surfaces and thus extinguish the fire. The  Twin Agent
System was fairly expensive to install in that it required a two pipe
plumbing job to every  hose station, the PKP required a neutral propellant
and the "light water" was about 100x the costs of old protein foam (animal
fat based). But it prevented MANY
catastrophic fires  and became a sailor's friend.  Cleanup was rinsing,
mopping with
precious fresh water on inside spaces and salt water (typical fire fighting
water) on topside or bilge spaces. We used to catch the engineers (grease
monkeys) using it to clean stuff because of the detergent content.
Finally, those of us who have alloys on our vans should know that once these
wheels catch fire, the only way to combat that fire is to keep it from
spreading (including burning the asphalt under the vehicle) and stand back
and watch the spectacular fireworks from the  class D metal fire...ala block
burning at some veedub campouts.
--
Stephen Steele
'91 Caravelle
'84 Westy
Chillicothe, OH