Thread: Brush & Forest - FOAM???
05-05-2000, 07:31 PM #1Paul GrimwoodFirehouse.com Guest
Brush & Forest - FOAM???
I am looking for your experiences in the RURAL SETTING of using either Class'A'Foam/CAFS/Fire Fogging Systems on brush and forest fires......?
Also, what about the addition of Class 'A' to the high-pressure water fogging systems - anyone tried that?
We have some light 4WD vehicles that carry small amounts of water out these sort of incidents. How will the various methods increase the capability of water (if at all) in comparison.
Wuld appreciate your feedback on this one.
05-05-2000, 07:59 PM #2Dalmatian90Firehouse.com Guest
Cuts down on our hand tool work considerably here in the hardwood uplands of New England
Most of our fires, fortunately, are human-caused (purposely or accidently) and near a roadway...so we usually use structural 1.5" hose to reach and knock down the fire. Used to be we'd also always cut a fire line around with rakes & brooms to clear the forest floor duff away and leave a 2'-3' band of dirt around the fire. Water alone ran off and was a little risky to be trusted by itself.
Now, we lay a layer of class A foam (from our primary attack engine) and/or CAFS from our service truck (which is a Humvee w/40gpm CAFS system and 200gallons of water)...pack up the hose and go home. Maybe use a rake and indian tank (backpack pump can) to break open and wet down punky logs. The extra drain time and wetting effect leaves a good line long enough for embers to go out.
This works fine for fall and spring time fires, seasons we get every year! Once maybe every 3 or 4 years we'll get a very dry summer and a summer fire season -- Class A helps, but we still cut fire lines because the duff and soil is so tinder dry...and usually a summer fire even if it's just an acre or so seems to take 3 days and 10,000 gallons of water poured on it in the morning and again in the afternoon before the roots go out. After the first batch of Class A helps wet the soil, not sure if subsequent stuff helps that much -- after all, we're just letting the water soak in over the acre or so.
05-05-2000, 08:59 PM #3town/deptFirehouse.com Guest
know here the water bombers put foam in the drop tanks. They say it works well.
05-05-2000, 10:32 PM #4FyredUpFirehouse.com Guest
Rather than retrofit expensive foam systems to older rigs we use the Scotty System for our class A ops. It uses a 4 liter jug that attaches to the end of the hose and meters class A foam at 1% for our garden hoses and has an adjustable eductor for the 1 inch line to go 1/2%, 1%, 3%, 6%. The garden hoses flow 8 GPM and the 1 inch flows 40 gpm.
Higher pressures make a more creamy foam and lower pressures make a soupier foam. it has worked great for grass and brush fires for us. The lack of repeated mop-up is the greatest benefit.
This my opinion yours may differ, have a nice day!
05-06-2000, 05:21 AM #5meshaFirehouse.com Guest
We have been using class A foam for brush/ forest fire fighting for some time now and it has proven beyond any doubt to stop advance along the ground. Besides water bombers using foam, ground crews use "scotty" around the pump foam kits. About the only time we don't use foam is when brush/ grass fires can be attacked with the use of our rolling stock and where a readily available supply of water is ensured.
walden Fire Department
05-06-2000, 03:08 PM #6Aerial 131Firehouse.com Guest
We use a foam system on my volunteer departments wildland apparatus called a blizzard.
It consists of a 5 gallon tank of Class A foam 1% with a metered ventura system behind the pump into the the preconnected attack line.
We then use two type of nozzles: A bubblecup, in normal mode it looks and acts as a regular nozzle. Pull the outside of it and it allows air to be added to water foam mix. The other type is the long tube (various sizes of diameter), at the base of the nozzle (about 18" long) are air intakes for air to be added to water/foam mix. Close them off and you get wetter foam or not close allows for dry foam.
We tried to use the CAFS sytem a few years ago and it did not work all that well. Lots of break down time on the air compressor and added weight to the apparatus. We now run Ford 350 Supers with 250 gallon tank and a Waterous pump with preconnects of 200' and hose backpacks of 100' with 100' laterals. With hand tools and water bladders(add about an ounce of foam) this works much better.
05-06-2000, 07:54 PM #7FirefrogFirehouse.com Guest
Paul, In South Australia the Country Fire service are using around the pump A class foam systems, a proportioner delivers 1% BFFF (bush firefighting foam) to all hoselines. This system is very effective, I have personally seen A class foams improve mop up time at bush/scrub fires by hours. I have done some research and the general belief is that A class foams do not assist greatly with actual firefighting (knockdown) but are very helpful in the mop up phase. The foam reduces the surface tension of the water and in my opinion makes a little water go a long way. Another method some trucks use when not fitted with proportioners is place a pre measured bottle of BFFF directly into the tank while on route to a showing fire (the configuration of our trucks allows for this.
05-08-2000, 11:27 AM #8monteFirehouse.com Guest
We have been using Class A foam in the wildland for several years, and deliver it using several methods. The most common delivery methods have already been mentioned, either using compressed air or in-line foam proportioners. The in-line confoguration can be either on the suction side of the pump head or the output side, also know as around the pump. All in-line foam pros rely on vaccuum suction, so the key to a good system is keeping the proportioner orifices clean. Any kind of air aspirating nozzle will work. Some better than others. The key here, is to get the right nozzle that is designed for the pump output. If you consistently get foam that is too wet, you will need to gear down the nozzle to a lower nozzle output volume. If you are working off trucks and have a need for just a few lengths of hose, the foam pro is good, an easy quick attack tool that is effective. If, as we are used to, using extensive hose lays, then consider either a caffs or a foam propo system that works effective from the smaller diameter hoses. Caffs will provide the best hydralics over a long distance and large elevational change.
We have used foam pros from truck installed units, to larger FLAMECO proportioners installed at an auxilliary pump at a porta-tank. We have adapted air aspirating nozzles to bladder bags, and with large fan systems that produce a low pressure, high volume foam that rolls dow the hillside and lays a 1-2 feet thick line of foam.
My experience with foam in several different fuel types in the western US, both ground base and aerial platform deliveries is this:
1) Foam provides a quicker flame knock down than water or water with "wet water".
2) Knock down is sustained longer because of the residual foam, and the surfactant properties.
3) Foam is not 100% effective on it's own. It requires the "same" dilligence and fundamental knowledge of suppression skills to put the fire out.
4) I have seen several rekindles in wildland fuels that are dense but relatively thin duff layers. The rekindles came from areas that appeared out, but retain residual fire until the foam properties were gone, the wind came up, and off it went.
5) Consequently, foam use requires the same thorough mop-up procedures as wet mopping uses.
6) Foam is an excellent tool for putting out difficult fires e.g. hard to reach areas, steep ground, deep and rotten bio-mass. Use thick applications, monitor routinely through the burn period, and continue to apply foam. Without commiting several personnel to a risking situation, you can put the fire out, with minimal risk exposure.
7) The largest deterrant to foam is personnel are inadequately trained to use it. That is, application rate and volume based fuel types, tactical use such as mobile attack, engine and aux. pump assisted delivery, hose size, nozzle capability, and crew configuration. Pretty much the same brew-ha as anything else we deal with.
Hope this helps.
05-08-2000, 04:22 PM #9Paul GrimwoodFirehouse.com Guest
Thanks for your valuable input guys - and for the detail in your replies.
OK - it seems that Class 'A' does have potential for wildland firefighting. Has anyone tried 'fogging' systems where bursts of fog are blasted into the burning brush? Hey - this has nothing to do with my previous posts on fog attack!!!
05-09-2000, 12:09 PM #10monteFirehouse.com Guest
I have not tried that method. However, thinking about it, it could have some application if you were looking at "knock down" potential for something specific. I contrast foam in some respects to aerially deliver retardent, either fugitive or liquid concentrate. A good deal of water delivered in the wildland fire environment changes the micro-humidity drastically. Retardent does this, and the rise in humidity stays high until the water evaporates leaving the chemical in place. Foam does the same thing, only it dissipates more quickly, as the bubles burst and the liquid evaporates of disappears into the fuel. Brush, or shrubs are usually comprised of small branchwood and leaves that absorb or transpire moisture quickly. Bursting foam into the crowns of shrubs would raise humidities I am sure that could easily affect the burning intensity. Longevity of the supressant effect would be my question. Like retardent, if ground crews are not available to take advantage of the reduced burning intensity, the effect is lost some hours later. With foam, I suspect it would be within minutes if the burning conditions were optimum. However, I tink the "knock down" would be effective, at least you could bring the fire out of the crowns of tall shrubs and put it on the ground where we have a better opportunity for control.
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