05-03-2001, 11:42 PM #1scottp711Firehouse.com Guest
Structural nozzle choice for Classs A CAFS?
My department has recently purchased a New Pierce Initial Attack Engine with CAFS and both Class A and Class B foams. Certain people have said that smooth bore nozzles are better than fog nozzles for class A foam in interior structual fire attack. Is this the case? Any studies on this? Does anyone run with departments that have experience with class A Compressed Air Foam Systems? What nozzles do you use? What about the wide fog for protection? Thanks in advance for the help.
05-03-2001, 11:55 PM #2LHS*Firehouse.com Guest
If I was using a pierce, and just finished training at Pierce I'd use what they've used, SM20 with CAF 3 to 1 water works pretty well. Followed by a 1 3/8 sb for special applications.
05-04-2001, 10:59 PM #3FirehoseFirehouse.com Guest
We are a small department in Louisiana using CAFS. there are many departments as well as firefighters that are more knowledgable than myself, but I will pass on what we have found.
We use an Elkart ball shutoff with a 1 3/8 slug tip. (we had these customised from 7/8 smooth slug tips) Using a ratio of 90 CFM air to 60 GPM water at .3 % class A foam and a pump pressure of 80 to 100 psi. this works for us as an excellent exterior attack line. Once we move inside, we add an SM-20 and up the pressure to 100-110. the combo fog nozzle squeezes the air out of the water making a wetter foam. You could also do this by increasing the GPM to 100 or so but watch the pressure. 100 psi is tough to handle .
Good Luck! What ever you find that works for you, let me know....there is ALWAYS room for improvement.
[This message has been edited by Firehose (edited 05-04-2001).]
05-04-2001, 11:13 PM #4FirehoseFirehouse.com Guest
05-05-2001, 09:21 PM #5Capt. LouFirehouse.com Guest
My department has been using CAFS for over 3 years now and is pleased and satisfied with it. For an interior attack we use the Elkart 1 3/8" ball valve with a 15/16" straight bore tip. We pump at 70 gpms and 30-40 cfms, with a main pump pressure of 100 psi, at 1250 rpms, and an injection setting of .3% for the Class "A" foam. This set-up works real good. If we need a dryer foam for exposure protection (shaving cream), we remove the 15/16" tip and flow directly from the open ball valve. We adjust the gpm flow to 30 and up the air to 60 cfms. We also increase the injection rate to .5% of Class "A" foam.
With regards to the use of a fog nozzle on a CAFS line, the fog nozzle strips the bubbles from the steam making a very "milky" wet stream. We do not use a fog nozzle for an interior attack for this reason, however we put the fog nozzle on for overhaul and we use it for brush and automobile fires as well. Remember the advantage of CAFS is the bubbles.
We have found that if a "wide fog pattern" is needed for protection or ventilation, the nozzleman will use his thumb over the tip of the nozzle. Like you would do with a garden hose.
The key to CAFS is training and education. Every member of your department needs to know all about CAFS. Just going for the seat of the fire with CAFS as a SOP is a drastic change from the broken steam off the ceiling we did with plain water. This is just a different and much better, efficient way of extinguishing a fire. Other basic tactics still must be utilized. Pulling ceilings, opening walls, ventilation etc. You still have to put the wet stuff (CAFS) on the red stuff. Just having CAFS on the fireground will not put out the fire. The other thing is that CAFS allows you to see were the foam is going or not going. I tell my firefighters that if you see the foam flowing around you ankles and the fire is not darkening down, then your not getting to the fire. Shut down and go find it.
Hope this helps. Stay safe.
05-07-2001, 01:54 PM #6mtperryFirehouse.com Guest
We have a squad with CAFS. We also use a 1" smooth bore tip or the tipless ball valve. We had an increadable fire season in 2000 and put the system to work on 3 20,000+ wild-land urban interface fires and found that wether we where laying foam line, fighting wild-land fire, foaming structures or fighting exterior class A fires (class B in one instance) that the smooth bore tip stayed on the hose. We would adjust our GPM's and foam concentrate from .3% - .6% and maintain pressure at 90psi, depending on how wet or dry we wanted it. Like it was said before the bubbles are what make the product you throw work. Happy foaming!!
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