1. #1
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    Question CAFS & Fog Nozzles?

    I am still not comfortable with the thought of CAFS being applied through combination fog nozzles. Surely the benefits of CAFS are defeated if the 'air' is stripped out at the nozzle? Also - if this occurs, where does the air go? Anyone using CAFS sucessfully through fog nozzles and if so - wouldn't a straightforward Class'A' line perform just as well?

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    Talking my experience

    In our intro class to CAF, the instrutor said that fog/combo nozzles defeated the point of CAF. Like you said, the bubbles are smashed apart as they flow through the teeth and nozzle openings. The air goes one way and the water/foam solution continues on.

    Our experience confirms this. Smoothbore if you want to have a bubbly foam. I think we're using POK brand.

    Another interesting thing: the turbulence in the fire hose itself actually helps build more bubbles and is part of the forming process of the finished foam.

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    We've shot CAFS through fog nozzles almost exclusively for 7 years. It works just fine. Out entire fleet of apparatus are CAFS equipped and all apparatus default to CAFS. I can think of another 50 engines using fogs exclusively.

    Two days ago we went 50 miles MA for a call for all available AFFF. When we got there we put the haz mat fire out with Class A CAF'd. The people requesting the aid don't know that. We used a 2000 gpm fog tip for several hours. It's the homogeneous bubble structure.

    At a series of live burns recently in Houston under the tutelage of their drill chief, the city guys thought the fog tip worked best.

    Seems to me if you came from the world of combination nozzles and like your firefighters to have options why wouldn't you want to offer them as many as possible in one package? If you can cover 100 square feet of wall, ceiling or flooring per second with a fog tip and only 5 square feet with a smooth bore why would you want to coat and cover less? The firefighter selects the pattern that is best. CAFS will travel at least 25% further than a Class A stream. If a Class A foam tip is used to aeriate the foam then the reach will be twice or further. Runoff in all our testing which anyone can do is at least four times higher with Class A and a foam tip and 10 to 20 times higher with a fog nozzle versus CAFS. Just apply on a vertical surface and use a stop watch.

    CAFS for structure fire attack is typically applied wet, not dry, thus 2 parts water to 1 part air or 3 to 1 is common versus 20 parts air and 1 part water for wildland and structure protection.

    You won't be shearing any bubbles at 2 or 2 to 1. Where does the air go? 30 cubic feet enters and leaves the nozzle. Wouldn't Class A work just as well? Nope. All the data suggests at least a 50% improvement with CAF over Class A in time to lower room temperature, water useage, etc. Drainage time is at least 4 times better.

    With a fog tip you won't see the over pressurization of the tip and the wide fog of a poorly supplied CAF smooth bore tip.

    We've spec'd "Fallon Tips" for CAFS use to offer a smooth bore for exterior work and a fog for interior work. Adjustable tips allow the nozzleman to set the air rate at the nozzle versus havig the engineer play with an air valve. We feel and know it is a safer operation. Our panels are preset for CAF and are not adjusted. It has been our experience watching others try to make CAFS the operators don't understand the rigs and screw things up. We've had dozens of FD's come to town to see how we have no fault CAF. The end of the day simple is better. Most new generations of CAF are simplified as well.


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    Our brush truck uses an adjustable fog nozzle on it. I don't know the type or anything but I do know it has no teeth. This truck is equipped with a CAFS system and to me it works great. We get good sud buildup and all. I don't know physics that well so... I also don't know the type foam we use, we got a broken 55 gallon drum for half off the regular price and like I stated earlier we have no problems.

    Also we did use the brush truck for a structure fire earlier this month and it did an excellant job containing the fire and putting much putting it out till the other trucks got there.

    Anyway, this doesn't explain the why but this post lets you know there are CAFS systems out there using adjustble fog nozzles.

    Any questions, I'll be more then happy to answer if I can.
    NREMT-P\ Reserve Volunteer Firefighter\Reserve Police Officer
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    Default Thanx.........

    Thanks for your input on this subject - it is fascinating!

    fcvfd (and Ryan) - Your experience is somewhat enlightening as it is not the usual approach in relation to the use of CAFS in structures. I say this only because I have not come across users deploying CAFS streams via fog-nozzles before. This concept counters many of the proposed benefits to be gained - it seems. However, you are the ones using it this way and successfully you say, so I bow to your experience on this.

    1. Most manufacturers appear to promote CAFS in association with smooth-bore nozzles for application in compartment fires. All the scientific research I have seen supports this notion.

    2. fcvfd - According to your information you are using CAFS from an interior position (at close quarters) using an 'indirect' (LAYMEN) application. With the higher cooling rate of the CAFS the steam production must be immense?!

    3. I cannot believe that the bubble structure of CAFS is NOT affected in any way by allowing it to strike the teeth of a fog nozzle? There MUST be some breakdown or 'stripping' of air and a 'milkier' product similar to Class 'A' foam produced?

    4. fcvfd - 'All the data suggests at least a 50% improvement with CAF over Class A in time to lower room temperature, water useage, etc'.

    What data? Is this YOUR data or that provided by a manufacturer? Can I see it if its yours?

    5. My understanding of CAFS (to date) is that it is used for rapid knockdown in compartment firefighting using less water to achieve this aim. It is applied from a distance, using smooth-bore applications and was never intended for close-quarter combat?

    I appreciate your input and debate.

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    ...What data? Is this YOUR data or that provided by a manufacturer? Can I see it if its yours?

    It used to be listed on the H20 or CAF forum but the god's took it away, I referenced Fire CHief Magazines LA COunty tests.

    http://industryclick.com/magazineart...magazineid=157

    ...My understanding of CAFS (to date) is that it is used for rapid knockdown in compartment firefighting using less water to achieve this aim. It is applied from a distance, using smooth-bore applications and was never intended for close-quarter combat?

    I wouldn't know there weren't any manufacturers for CAFS/WEPS when we started uning the stuff in 1979. I doubt the manufacturters fight many fires. Most of the panel layouts and concepts they have shared with us certainly show no end user experience.

    Recently we had to explain to the largest CAF builder how to plumb 7 ladder trucks. None of the rigs another builder supplied 9 to be exact would even make foam. In another case teach them how to make the system work via a front bumper discharge. Another we had to teach them how to freeze protect the compressor. Other departments have come out to try and figure out at our place why their rigs didn't work. Nah, not to impressed with the complexity or lack of understanding or how to use the agent on fires.

    ...I cannot believe that the bubble structure of CAFS is NOT affected in any way by allowing it to strike the teeth of a fog nozzle? There MUST be some breakdown or 'stripping' of air and a 'milkier' product similar to Class 'A' foam produced?

    Seems to me Class A foam is very large runny bubbled, not small milky sticky bubbled. The big bubble break ad the water runs off with Class A mechaical aspirated foam. The other night one of our ladders pumper for several hours on a mutual aid fire, we could always tell our CAFS from a fog tip from anyone elses Class A.
    Last edited by fcvfd; 02-02-2002 at 04:26 PM.

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    The LA County applied CAFS from exterior positions using a one inch smmoth-bore for these tests so the data you use is not relevant to CAFS through fog-tips. However, I accept your viewpoint that the CAF you produce is of good quality and bubble structure.

    I presume you applied CAF through smooth-bore tips prior to 1994 - why did you change? You still prefer to apply indirectly at close quarters despite the steam hazard?

    Also - you mention the recent Houston live burns where the guys preferred CAFS through a fog-tip as opposed to smooth-bore?? Again, what is their application....a LAYMEN approach?

    I am very interested in this use of CAFS and again, appreciate your views and experience.

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    ...The LA County applied CAFS from exterior positions using a one inch smmoth-bore for these tests so the data you use is not relevant to CAFS through fog-tips.

    Yeah and our lines are 50 feet longer than theirs, we have better mixing chambers built into our lines, use a cosmetic grade foam, so we have better foam output via a combo nozzle than they have with a smooth bore. It is quite easy to measure with a graduated cylinder, a stop watch and scale. Yeah, we measure performance. Even though all the experts say you can see the difference I like to measure to be sure. Oh, yeah we have used their trucks in our town. We use more water to and have what 15 years more experience. All the data about CAFS from day one is a constant repeat of performance.

    It ain't the nozzle it is the ratio of water to air. The finished foam puts out the fire however applied. Kinda like a SB versus combo nozzle. Both in the same pattern accomplish the same task within a fraction of a second of each other. The fog pattern will eat more heat. If you leave it open too long it will create steam. CAF is the same. My experience if everything is white the materials are not releasing steam anymore or smoke. All the test support the same.

    Clarence Grady, Pierce's CAF gutu was doing CAF at a CC in Oregon in 1985. All homemade stuff. Every class he teaches he teaches the option of a combination nozzle. Most of the time an Elkhart Auto. A lot of his customers are using just that tip everyday.

    ...I presume you applied CAF through smooth-bore tips prior to 1994 - why did you change?

    Nope, Used Turbo Jets (colse to 100 rigs had them with CAFS/WEPS) or TFT's with CAFs and if needed took the fog break apart tip off for SB exposure/exterior wildland work. You see if you use an automatic nozzle versus a smooth bore and anything back then happened to the air valve or foam, you'd instantly transition to a water stream, not so with a smooth bore.

    ... You still prefer to apply indirectly at close quarters despite the steam hazard?

    Tell you what, after 7 years a few hundred structure fires a year, all interior work if the structure allowed for it, I can assure you there is no more heat that when we used plain water or just Class A from a combo nozzle. I doubt anyone can recall being steamed. We open the nozzle knock the room down and overhaul. We try to remove glass and almost never vertically vent for 99% of the fires.

    ...Also - you mention the recent Houston live burns where the guys preferred CAFS through a fog-tip as opposed to smooth-bore?? Again, what is their application....a LAYMEN approach?

    200 feet 1 3/4" hose, a TFT or Turbo Jet interior attack. They like us applied it like water. No special rules, set an EP and go put the fire out.

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    fcvfd - 'we have better foam output via a combo nozzle than they have with a smooth bore. It is quite easy to measure with a graduated cylinder, a stop watch and scale'.........

    I would very much like to see some of that data if possible - you can e-mail me. If you are getting better quality CAFS with a combo when compared with a smooth-bore I am most interested in seeing some of your measurement data and the set-up used to achieve this?

    What is HOUSTON's (City) official approach on applying CAFS into structures at this time? Smooth-bore or fog (combo) nozzle?

    Can a CAFS 1 3/4" line be 'pulsed'? Is there anything that would upset the foam quality, damage the line or pump or CAFS mixing equipment if short bursts (pulses) are applied?

    In Texas do you think combo applications are more common than smooth-bore for CAFS in structural settings?

    Thanx

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    Just for clarification on my eariler post, we do not normally use CAFS for structure fires. The only reason we did this one time eariler this month was that we were on scene of a MVC with our rescue van and brush truck and were clearing when we got a call for a structure fire. The brush truck responded straight to the scene while other personnel went to get our pumper and tanker.

    If we could take the CAFS off our brush truck on put it on our frontline tanker or something then I would love to experiment on the subject of this thread.

    Hopes this explains any questions you didn't have.
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    Post Pulsing CAF lines

    There is nothing wrong with slamming nozzles open and closed with CAF. There is no water hammer because the ability of the CAF to compress in a spring-like fasion prevents a shockwave from being sent back to the pump, etc.

    We were encouraged to always "slam it open" when starting to flow a line. There is an initial "burst" that lasts 2-3 seconds due to the build-up of pressure in the line, and it throws your stream a bit further.

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    To fcvfd:

    We are about to put out to bid a CAFS rescue pumper.

    What's the deal with the plumbing/front discharge??? How about freeze protecting the air compressor?

    Every vendor either has a different answer or no (understandable) answer regarding CAFS.

    What manufacturer(s) really know how to make it all work?

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    ...What's the deal with the plumbing/front discharge???

    You'll need a check valve in the line to keep the air from putting the pump into deep cavitation that the primer cannot solve.

    ... How about freeze protecting the air compressor?

    The compressor needs to be mounted at least a 3 degree angle to allow drainage.

    ...Every vendor either has a different answer or no (understandable) answer regarding CAFS.

    That is my experience. And the answer and solution varies from truck to truck.

    ..What manufacturer(s) really know how to make it all work?

    All of them do, but it seems hit and miss between rigs. SHot for simple, determine exactly the flow you wantout of a discharge and optimize the system for that flow. System that try to do everything don't work.

    Ask the builder to tell you step by step how to flow CAFS out of a cross lay for example.

    OURs:
    1. Engage pump
    2. Throttle up to 120 psi
    3. Open the discharge fully
    4. Now you are ready to fight fire.


    Most others:

    1. Engage the pump
    2. Engage the compressor
    3. Throttle up t 150 psi
    4. Turn the foam system on
    5. Set the percentage
    6. FLow water out of the attack line
    7. Gate back until just 60 gpm of foam water solution is flowing
    8. Turn the air on
    9. Adjust the air to 30 or 45 cubic feet.
    10. Now you are ready to fight fire.

    If is is that hard it will never be used. Thus most systems don't get used.

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    Larry - thanx for your information to date but I am receiving a lot of feedback from users and manufacturers that fog nozzles should NOT be used with CAFS. Now, I appreciate your viewpoint that good quality CAF can be produced through fog nozzles but still have not seen any documented evidence. You suggest that your measurements demonstrate better foam through fog tips than LA achieved through smooth-bores. Can you share that evidence with us?

    Also - there were a few Houston firefighters on here a week or two back - What is HOUSTON's (City) official approach on applying CAFS into structures at this time? Smooth-bore or fog (combo) nozzle?

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    Hi Paul,

    This is not rocket science. Think about how a fog nozzle works. Its purpose is make smaller particles of water out of a straight stream of water. Hence the word fog. It only stands to reason that if CAFS makes small uniformed bubbles, that the bubbles will be and are destroyed as they, pass threw the "fog" nozzle. You are basically applying a foam solution when using a fog nozzle. The best advantage in using CAFS is to use a an open bale with a reduced straight bore tip on it. You get superior reach, penetration and fire knockdown capabilities with this set up and still maintaining a high level of safety for the attack team. The whole purpose of using a CAFS system is take advantage of the bubbles. If the fog nozzle strips the bubbles, which it does, then if defeats the purpose of having CAFS. You might as well save the cost of a CAFS system and just use a foam injection only system.

    Our department uses an 1 3/8" ball valve with a 15/16" tip on it for interior attacks. It works very well. For a dryer foam we remove the tip and increase the airflow to make "shaving cream (expossure line). We also use a fog nozzle on CAFS, but for automobile fires, overhaul and small piles of leafs on the side of the road. These are instances were ff safety is not being compromised for the task at hand.

    Hope this helps.

    Capt. Lou

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    Snorklehuh?

    I'm amazed Larry at the number of names you log on as. Is it worth it?

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    SnorkleHuh,

    As soon as you said that 4 letter word, "HALE", it all comes into focus!

    Are you referring to the "Hale" that does not offer or manufacture CAFS? And are you referring to the "Hale" that got out of selling CAFS some 3 years ago because they couldn't "get it right"?

    Now I understand why you can't understand my comments. So explain to me why would I even think of "coming to Hale" for CAFS related information?

    You’re the one that should be looking, not me!

    Capt. Lou

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    Larry:

    Have you ever done an NFPA 412 Foam Expansion test both with class A and CAFS using all types of nozzles?
    Kirk Allen
    First Strike Technologies, Inc

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    Wow Larry,

    I guess now when they kick you out they not only kick you out but your posts as well.

    The reason I asked about the foam expansion test is because those facts take all the arguments away as to which nozzle offers better expansion.

    We found that at the same flow rate and the same percentage the CAFS delivered from a combination nozzle had less expansion than that from an aspirated nozzle or a smooth bore. Why? Simple logic would assume that the stem in the combination nozzle is stripping some of the bubble structure. Do I know for sure? No, thats why we did an actual expansion test.

    I personally think that if you going to use CAFS you should not do so with a combination nozzle and despite your arguments saying it works fine with it Larry, simply look at you own post showing the Fallon nozzle and other posts of yours that clearly stated the smooth bore tip was for CAFS. (Sorry, you may not be able to go back and look at your posts but I think you get the point.)
    Kirk Allen
    First Strike Technologies, Inc

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    Thanks for that information Capt and KEA which is pretty consistent with what I am told by all. However, I remain open-minded! If you want to re-appear behind another mask 'Larry' then I would be happy to hear what Houston's official line on this is?

    Capt.Lou - is that true about Hale? I have noted that there is nothing (I can find) on their websites about current CAFS products and yet they are promoting CAFS in the UK.

  21. #21
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    Originally posted by KEA


    Have you ever done an NFPA 412 Foam Expansion test both with class A and CAFS using all types of nozzles? [/B]
    Could you explain this test? Thanks.

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    John_Ford

    Tbe NFPA 412 Standard, "Evaluating Aircraft Rescue and Fire-Fighting Foam Equipment" outlines how to do the above mentioned test.

    Section 4-3.2 outlines how to do the test.

    Without going it to great detail, the information gathered in the test is put into the following equation.

    Expansion = 1600ML divided by "Full weight minus empty weight in grams"

    This standard also outlines how to measure the foam solution to determine your getting the right percentage.

    Although this standard was originally designed for Class B agents, the testing can apply to any liquied agent.

    If you dont have access to the standard let me know and I will email you some more detailed information. If you have an airport with its own fireprotection you should be able to get a copy of it from them.

    Unfortunatly it seams that most airport departments only do the percentage testing and have never done the actual expansion testing for their equipment.


    Not to change the subject but I have tested foam solution for proper percentage and found that all to aften folks are not getting the percentage they think they are. Class A is not as criticalas class B when it comes to actual suppression, however cost can become an issue if your really getting 1% when you only dialed to .5%.
    Kirk Allen
    First Strike Technologies, Inc

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    Hi Paul,

    From what I know, Hale stopped selling their "Cafs Master" in the US about 2 or 3 years ago. Why they are selling it in the UK and not the USA is a question for Hale. It does not make sense to me.

    I have heard through the "grapevien" that the are planning to get back into the CAFS market. I heard this and do not know it to be a true or not.

    Good Luck,

    Capt. Lou
    "Got Foam"

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