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CAFS
With the fire service ever evolving to become a better service provider to our general pubic, I wanted to talk about CAFS. CAFS is compressed air foam systems for those whom are new, or have never heard the term. I was never a believer that something without a lot of water would become a great provider of fire stoppage until being able to work with CAFS on 3 seperate occasions. Keep in mind, I am forming my opinion here based on my own experience, so if it is something that doesn't seem right, I haven't spent hundreds of hours with the system components yet.
We don't have a CAFS equipped engine on our fleet. (yet) Our neighboring department is a firm believer in CAFS and use it every opportunity they can. It can be flowed through any hose type from forestry (we have used it for this) to standard operating nozzles for 1 and 1/2"-2 and 1/2 " interior nozzles to deck guns. Although you use less water, CAFS can be propelled a further distance than some basic hose streams. You can pick up a 200 foot shot of 2 and 1/2" hoseline and advance it readily with 1 operator. (I'm no incredible hulk but its quite possible to do easily)
My observations are this. Interior dwelling fires (one fed by a ruptured oil line to the furnace) had complete knockdown in an amazingly rapid way. I was shocked that for a house that under normal circumstances would have been decimated was helt to 3 room and contents fires. (exterior walls to the inside of the house via open windows) By covering the surface you are spraying (and also staying there for a while) you are removing the heat and also the oxygen. I was quite impressed on the fashion the heat was removed with little ventilation. We flowed 888 gallons of water and just a ssmall amount of foam for the entire job. For car fires a fire you would normally flow 500 gallons on you are putting out in 100 gallons or less.
Whats not to be impressed with? Complete service, lighter hoselines, total knockdown, less rekindles (yes with proper overhaul) and the room and contents fire on the second floor no longer ruins the interior downstairs. A minor fire causes minor water damage now. If you haven't had the chance to use the stuff, take my word its great!
If you do use it, add to the storyline of great successes or downfalls. Cafs in my eyes is the way of the future, may as well plan for it now
We don't have a CAFS equipped engine on our fleet. (yet) Our neighboring department is a firm believer in CAFS and use it every opportunity they can. It can be flowed through any hose type from forestry (we have used it for this) to standard operating nozzles for 1 and 1/2"-2 and 1/2 " interior nozzles to deck guns. Although you use less water, CAFS can be propelled a further distance than some basic hose streams. You can pick up a 200 foot shot of 2 and 1/2" hoseline and advance it readily with 1 operator. (I'm no incredible hulk but its quite possible to do easily)
My observations are this. Interior dwelling fires (one fed by a ruptured oil line to the furnace) had complete knockdown in an amazingly rapid way. I was shocked that for a house that under normal circumstances would have been decimated was helt to 3 room and contents fires. (exterior walls to the inside of the house via open windows) By covering the surface you are spraying (and also staying there for a while) you are removing the heat and also the oxygen. I was quite impressed on the fashion the heat was removed with little ventilation. We flowed 888 gallons of water and just a ssmall amount of foam for the entire job. For car fires a fire you would normally flow 500 gallons on you are putting out in 100 gallons or less.
Whats not to be impressed with? Complete service, lighter hoselines, total knockdown, less rekindles (yes with proper overhaul) and the room and contents fire on the second floor no longer ruins the interior downstairs. A minor fire causes minor water damage now. If you haven't had the chance to use the stuff, take my word its great!
If you do use it, add to the storyline of great successes or downfalls. Cafs in my eyes is the way of the future, may as well plan for it now
Replies to This Discussion
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Permalink Reply by Firegal77 on
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YES!!!!! I love CAFS. On my department we got a new CAFS truck a couple of years back. It was so new, that no one knew how to use it, and it was intimidating. Well, I took the challenge and it became my baby. ( My fellow firefighters lovingly call me CAFS mama) I spent hours, days, weeks, figuring it out, and once i got all the ratios worked out it was a great thing. Let's start with the troubles i had first....
#1 the inductor was easily clogged when we first started using it, due to the pipe goop from the new fittings. I found out quickly that a wire coat hanger fits just perfectly into the hole for clearing it
#2 If you don't flush the pipes a bit and close the valves to your hose and recirculate, then you will have foam coming out of every possible crevass of your truck
#3 if the operator shuts down the nozzle during use with out the former steps being taken, the former incident will occur.
# 4 people are simply intimidated by it, and so tend to panic instead of using common sense to use the logical order of things.
#5 If you run water into the line before you turn on the air, your nozzle guy is likely to get knocked on his a**. The air behind the water causes a water bullet that has a hell of a kick. (I admit to having a few laughs over this one, but no one got hurt....honestly)
#6, If your hose has kinks, or you are running the wrong mix, the hose will start bucking pretty hard, and is awful hard on those attempting to hang on(again caused a few misguided chuckles...sorry)
Now to the benefits..... Along with what was stated earlier by 913, it will stick to the walls of a structure like shaving cream for about a half of an hour in favorable conditions. This works well in wildfire situations. While on a fire in Colorado, we were in a neighbor hood that was tucked into dense forest, and vegetation. It was brought to the table whether or not we felt we could protect those houses. Of course almost all of the wildland crews said H-E double hockey sticks no! I then offered another solution. I volunteered(with their consent) my crew and CAFS truck to take care of the situation. While other crews were mitigating around as many houses as possible, we were running up to the houses and covering them in foam ahead of the fire. Then getting out of the way before it got too dangerous. Fortunately the fire turned just befor hitting the houses, but i still thought it was a great idea...no lives at risk there, and at least offered a chance at protection.
The other great thing about CAFS is that it doesn't destroy the house afterwards. It simply rinses off and is nontoxic, unless of course you are dumping it right into a stream( "they" recomend at least 50 feet from the stream)
It can be used to fill the entire interior of a structure if necessary. Obviously you don't want to do this if it is someones home, but, works great for airplane hangers, etc. On a fire line I also came up with another useful way to employ the cafs. On the rear port of the truck, i put a "Y" on and 2 nozzles. I was able to lay a double wet/foam line all the way around a grass fire without anyone operating a hose, just pumping and rolling.
Those of us that have done wildland fire know what a pain in the a** those smoldering logs can be...by covering them in a blanket of foam, it allows you to continue fighting the fire without worrying about the log reigniting( though one must still go back and break it up with a pulaski....sorry, no way around that.)
By foaming down trees on the opposite side of the line, or exposures near the blaze, and it allows you to quickly provide coverage without having to keep a hose man on the job(as i said it will last fairly well for a half of an hour- this could vary from location to location depending on climate and weather)
I could go on and on, but will leave space for others....may come back to add more later...
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Permalink Reply by Joe Stoltz on
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bump
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Permalink Reply by Engineco913 on
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Actually it is funny, I forgot this post. I read an article a few weeks back about CAFS. It was a LODD report from overseas where 2 firefighters were killed when their hoseline was burst from excessive heat. (the fire wasn't out when they kept advancing) We all need to spend a little extra time to ensure the fire is out before moving too far inside. There is a lot less water involved so the thermal cooling is limited, and hoselines become suspect. Use your heads and train as you fight to ensure you are proficient in CAFS.
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Last year we bought a new truck that came equipped with what I'd call a "poor man's" CAFS system. It's really class A foam solution at 1/2 or 1 percent applied through a high pressure booster line with special nozzle. We haven't trained with it yet but I'm pretty doubtful that it would perform like a true CAFS system, no matter how much hype they give it. I may be pleasantly surprised, but GPM is GPM no matter how you cut the cake.
Does anyone have comment about the extra expense associated with CAFS, like maintenance, equipment repair/replacement, or other issues?
It would be nice to see an actual live demo of a true CAFS system in action.
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Does your system have compressed air?? If not, then it wouldnt be considered CAFS(Compressed Air Foam System)
Go to www.youtube.com and type in CAFS or Compressed Air Foam in the search box. There are several demos of it's use there that you can check out! ( particularly liked the test on polar solvent because I felt like it gave a good over view on how little it takes to put out the fire and minimizes clean up and water damage.
As far as maintenance, the foam is corrosive as I am sure you know, but with good maintenance on the system and making sure you are flushing the lines you should be able to extend the life of the system over all.
I cant guess on the cost of converting to CAFS. You will need to plumb the truck with airlines and inductor. And if you arent currently runnning with smooth bore nozzles, then you will need to get some of those for the operation. All that old 1 1/2" hoseline will get used again though!!
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Oh yea, and of course you will need an air compressor if you dont already have one, and it should be capable of up to 70 CFM(the maximum amount of airflow that can be used to produce effective foam in an 1 3/4" line).
Also, as a side note, I have read that they are now producing a NAFFCO CAF additive that boosts the foams ability to stick to verticle surfaces making it more effective for longer periods of time.
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I never thought about that before!! I guess it makes sense! Though, sadly, i dont have to worry about it as the guys over here dont seem to embrace the use of CAF...sigh However, it is useful knowledge!
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The cafs a neighboring department uses (we used in a basement fire) was the perfect mixture. The cafs stuck to the underside of the floor joists like a fire extinguisher would, and knockdown was almost immediate. It has it's place like everything else, just takes a little longer to break old habits for some people
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No, we don't have a compressor... so I guess in this case CAFS means "Class A foam system" instead of the REAL deal.
How, or why it came equipped like this, I don't know.
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Permalink Reply by Jackson on
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CAFS's use Class A foam (usually), but there are many systems that have an eductor and use Class A foam without compressed air. The foam decreases the surface tension of the water and allows it to penetrate into cellulose fuels. There are several different ways to introduce air into the water/foam mixture without having an air compressor.
An assortment of nozzles is available that can be used at the end of the hose that aerate the mixture. These nozzles will produce a foam that is much wetter, or has a higher water content than CAFS foam, but you still get a lot of bubbles that will provide an insulating layer on a horizontal surface. It does not cling to vertical surfaces as well as CAFS.
Let's start with the low expansion foam nozzles. The cheapest is the Madd Dog nozzle. It works very well.
Another is the long tube type nozzle, like HERE. They also work very well.
You can also move up to a medium expansion foam nozzle. They are much larger in diameter than a low expansion foam nozzle, but produce many times more foam. HERE and HERE are examples.
And then there is high expansion foam. It takes a large piece of equipment to generate high expansion foam. It is sometimes mounted on the back of a pickup truck and uses a large fan powered by a gasoline engine or it may use the flow of water to power the fan. These can generate huge amounts of foam. Some aircraft hangers have them fixed-mounted on the ceiling and they can completely fill the hanger if needed.
Ron Rochna has some information about using high-ex on wildland fires:
"High Expansion Foam flows easily down slopes without any breaks in the barrier when applied on brushy or timbered slopes. The steeper the slope the faster it spreads. When using a FP-50 Hi-Ex foam generator with a 750:1 expansion ratio, flowing 65 GPM of 0.5% foam solution will generate 49,750 gallons of Class A foam per minute. The massive amount of bubble flowing down a slope is overwhelming. The bubbles create a straight, wide barrier, without any dog legs, ideal for holding or burning out from. On one incident, a barrier over 2000 feet, 100 feet wide, and 5 to 10 feet deep was created with just 4000 gallons of water and 20 gallons of Class A foam concentrate. The fuel was heavy timber, tanoak and brush. Utilizing gravity to move Hi-Ex foam down a hillside eliminates human errors of not applying enough foam to wet the fuels. "
HERE is a link to a photo showing high-ex flowing down a hill.
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Permalink Reply by jeremy mankin on
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we have had caf every sence they came on the market the old timer did'nt understand it at first. the first time we use it was on a moble home fire . they whated for approx 15 min before they called 911 this is 3:00 in the morning and 5 miles from station. it was a water heater fire and got in the walls . we only use 320 gallon of water and 1 gallon of foam . this sold the older men on the department and now we don't order a truck with out it
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