Originally Posted by
Gordy
Finally---someone else who understands the "fire triangle"....helicopters do NOT put out fires---we "cool em down" a bit, allow em to be steered, or with retardant we take away the O2....Now all we got to do is convince the average wildland firefighter that its OK to "talk to me on the radio", and feel free to use your "signal mirror", (cheapest peice of equipment on a fire---works better than the radios...),--Telling me "I'm on the ridge top" helps me how??????
Sorry for jumping in here, but I couldn't resist in that someone mentioned that water removes the oxygen leg from the fire triangle, or at least that is how I read it.
In all do respect I don't believe dropping retardent or water/foam removes the oxygen from the fuel in the fire triangle (and if it does, its a fluke). More likely your coating the fuel that is to burn with something that protects the fuel from a heat source but not allowing it to ignite (insulation barrier like drywall in a structure).
For those that might need a quick refresher, read on: As I recall the fire triangle components are: Heat - Oxygen - Fuel. Take any one of the legs away and the fire goes out. Removing the fuel leg is great and its done all the time with fire breaks/lines. Removing the heat leg is also another primary tactic for direct extinguishment and that is done by removing the heat (using water - rain, hoselines water drops). Removing the oxygen is a hard thing todo incase you happen to have a bubble to put over the fire LOL. Some foams can do this, but for a short period of time on Class A fires (woods and normal combustibles.
Retardent coats the fuel with an insulator and slows the burning process down to help steer the fire, or reduce the flammability of vegetation, houses, trees etc (aka fuels). Typically retardent is applied in front of the fire (going indirect as some call it) in much the same way a dozer line or handlines are put in. But a retardent line isn't as effective though, but the quickest in hard to reach spots or resources are slim. If a retardent line stops the fire, we have to go in a put in a handline in case of a flareup as we don't trust drops 100% for containment.
Water wets the fuels for cooling (removing heat this collapsing the fire triangle) and is best applied directly to the fire for extinguishment and picking up hot spots for us ground pounders. Adding a bit of foam solution (up to 1% Class "A" solution to a load) to the water reduces the surface tension and allows the water to soak into the fuel with more effiency to cool whats burning inside of a down tree or what not. Instead of the water beading up and running off, the water/foam solution can penetrate into the porous wood, bark, ground fuels and grasses to cool and extinguish. It can be applied prior to a fire front, but only a few minutes prior though, because a fire front being pushed by wind can dry out anything out infront of it.
Lastly, I would like to thank all of you that support us from the air. Your greatly appreciated, and your the real heroes in my book!
