Thread: Fwd: CAFS System
01-26-1999, 07:58 PM #1
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Fwd: CAFS System
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CAFS posted 01-26-99 18:48 ET (US)
As part of our design, we are planning a CAF system on our new pumper. Although in use in other areas, this system has not seen service locally. Comments on CAFS range from "It's the way we will all be fighting fires" to "It returns us to being curbside firefighters." We tried a demo unit and were impressed with its application on vehicle fires and on a small barn. We are aware of the kinking hose issue and used the non-kinking variety. Concern for the lack of protection of a waterfog cutain was recognized. We are interested in your comments either for or against these systems and especially those based on hands-on experience in day to day use. The manufacturer,model and its application would be appreciated. Thank you for your thoughts on the subject.
01-26-1999, 08:36 PM #2ECBURTFirehouse.com Guest
<"It returns us to being curbside firefighters.">
I've been lucky enough to work in a state where Texas Snow Job, WEPS and Cafs are in there 2nd and 3rd generation of apparatus. It can be used from the exterior or interior. The choice is yours. Folks like Boston have demonstrated they only needed half the water with CAFS.
Every major pump builder offers it. Phoenix only buys CAFS engines.
<We are aware of the kinking hose issue and used the non-kinking variety.>
In the city our company has done 1600 fires with cafs. We Caf all fires. Never had a kinking problem in the last 4 years.
<Concern for the lack of protection of a waterfog cutain was recognized.>
We use a fog tip all the time with cafs so we have protection. I think it is the way to go and have spec'd 7 CAFs units in the last couple years for city and rural fires. We set the rigs up so foam is always on, requiring a conscious decison to turn it off, which just about never happens. Lines move quicker with cafs, the crew does not take the beating from heat and steam, and damage to contents. Just buy from someone who have made lots of cafs units. I know where rigs are sitting for 3 years that never worked. I'll tell you who if you want to know.
<based on hands-on experience in day to day use. The manufacturer,model and its application would be appreciated.>
I've worked with Hale, Darley, Pneumax and Pierce. Like Pierce and Darley best. They always work. Our dept sops are cafs only all the time so we use it all the time. To make CAFS all we do is throw two switches in the cab, throttle up to 90 psi and open an attack line . No different than spraying water. If you make it hard add lots of controls it will never work.
01-27-1999, 09:38 AM #3tnls1Firehouse.com Guest
Thanks for the info. We have been in cafs for 15+ years and with the foams getting better
we have been attacking everything with CAF. We are needing info on the hale 200cfm system
that is spec for our new unit. If you have a fog tip for protection what type of foam do you get ? When we add any restrictions to the hose we get a very good wet soup not the foam
cafs are famous for. Our units range from 20gpm/20cfm to 500gpm/200cfm with a 2-1/2 discharge that darkens down a fully involved
frame structure real quick. The small units
are older american fire and the large unit is a magee cafs system both out of texas.
01-27-1999, 11:34 AM #4ECBURTFirehouse.com Guest
<We are needing info on the hale 200cfm system that is spec for our new unit.>
I guess if you've limited yourself right out of the box to Hale, andhave sent out a spec already, you don't need anyone's information but Hales. Call Boulder Rural Fire Protection District in Colorado and ask why after 3 years the most expensive engine in Colorado does not make foam, it is a Hale Cafs Master. Ask them about support, ask why all their neighbors are buying CAFS but not from Hale. Possibly putting another $40,000 into the rig and it will make foam one day. Ask for Len Cremins, Fire Board Preident or Bruce Mygatt Fire Chief at 303-530-3315 or email@example.com.
<If you have a fog tip for protection what type of foam do you get ? When we add any restrictions to the hose we get a very good wet soup not the foam cafs are famous for. >
Research has shown the ideal CAFS for structure firefighting is 1/3 air and 2/3 water. The fog tip makes the perfect interior CAFS. You need water to cool and put out the fire. If you go 1/3---2/3rds you'll use half the watrr.
The dry foam is for structure and wildland firefighting is made with a smooth bore.
01-27-1999, 12:46 PM #5CAFSFirehouse.com Guest
Thanks "ECBURT." If you got a minute, maybe you can elaborate a little on the use of fog nozzles with CAFS. Everything I understand about that setup tells me that there is a degradation in the foam. You get more of a the foam associated with a proportioning or eductor unit than a CAFS. Is that right? What's your thoughts on The Snuffer which offers several configurations both as a self contained motorized slide-in unit to a hydrostatically driven add-on unit for a regular pumper
[This message has been edited by CAFS (edited 01-27-99).]
01-27-1999, 01:37 PM #6ECBURTFirehouse.com Guest
<Maybe you can elaborate a little on the use of fog nozzles with CAFS.>
It works just fine. I see Hazen NB uses fog tips as well. The most knowledgeable with most experience in CAFS in our country teaches it as well.
< Everything I understand about that setup tells me that there is a degradation in the foam.>
A bit but water puts out the fire and you simply need more water than air for interior firefighting.
<You get more of a the foam associated with a proportioning or eductor unit than a CAFS. >
I don't understand the question. We operate at .003% versus .05 to .01% with an eductor.
What's your thoughts on The Snuffer which offers several configurations both as a self contained >
I like injection versus eduction. The company that buildsthe Snuffer has built a bunch of CAFS units so it will work.
01-29-1999, 02:42 PM #7CAFSFirehouse.com Guest
ANOTHER TRY AT MY QUESTION
Perhaps I didn't explain myself properly. Please bear with me if I sound a little long winded here. My understanding is that Compressed Air Foam Systems work best when the stream is ejected without a restricting nozzle normally consisting of a quarter-turn ball valve that lacks a significant stream shaping devise such as a smooth bore tip or fog nozzle. Sometimes a smooth bore tip can be used to extend the reach but at the expense of the quality of the foam. I am no engineer here, but the foam is already pre-made in the hose in a CAF system under optimised ratios and conditions and any further mechanical agitation will break it down from its ideal composition. A nozzle subjects the fire stream to mechanical forces as it is constricted in an effort to shape a particular pattern. Thus the agitation, friction and disturbance or whatever you want to call it breaks up these perfectly formed bubbles. By comparison, when a foam induction unit is used or for that matter an eductor, foam is not generated until the stream leaves the nozzle and air is entrained in the stream. Only at this point are foam bubbles are formed. As this aspiration is done in less exacting conditions, more agent is required and the quality of the foam is also not optimised. The bubbles themselves vary in size, some are oversize and are "wetter" with plain water mixed in. Similarly, when CAFS foam is forced through a nozzle it is in effect "beaten up" as it passes through the nozzle. Furthermore, when using a fog application CAFS foam is subjected to reformulation by this external mixing with less than the optimum amount of agent needed to make "external" foam since CAF systems use a less agent to achieve optimum foam.
The foam produced by fog nozzles has less reach, doesn't adhere as well to vertical surfaces, bleeds down more readily and encapsulates the combustibles less effectively requiring reapplication and hence slower knockdown. The shaving cream produced from a CAFS allows for the paint it and forget it technique and hence the more rapid knockdown. Visibility is a added benefit.
My earlier question then, relates to the dilemma the above seems to pose. As we have not had the benefit of using CAFS over numerous real life evolutions, I may be overstating the problem. Can you mount a safe internal attack with a quarter-turn ball valve on the end of the hose line from which you cannot project a protective water curtain as you could from a fog nozzle or do you sacrifice the ideal foam made in a CAF system and slap on a fog nozzle to give you some added insurance? There is a lot of field experience out there. Thanks once again.
01-29-1999, 04:02 PM #8tnls1Firehouse.com Guest
It appears that you have a good understanding of CAFS, how they operate, why they have great knockdown and are questioning the use of nozzles over smooth bore shut offs. We have never been able to achieve true foam with a fog tip on the line. We have gone to the fogs to get better penetration in bulk materials. If you are able to make entry to the involved area you will be able to put it down. We too have seen the progress from the Forestry WEPS to current cafs and are learning from live training sessions on abandoned/donated structures.In tests between
CAFS, CAFS w/fog and air asperated attacks on
fully involved 1 and 2 room dwellings the CAFS was by far a quicker knock down, we have
done over 100 training fires in actual dwellings with our large CAFS with straight bore lines with only casualty being radiation/steam burnson the thigh area from waiting at the door to long and letting it roll over before hitting it. We utilize the stored energy in the hose line to work on the fire and SOP is to hit it full open to prevent the breakdown of the foam. Also in response to the earlier comments about the Boulder unit...the unit is an aux. diesel unit for pump&roll and works well at sea level but loses the HP altitude.Thanks for the information and the discussion.
01-29-1999, 04:22 PM #9ECBURTFirehouse.com Guest
<works best from ball valve, a smooth bore tip can be used atthe expense of the quality of the foam and reach >
That is the ideal way to make a thick dry foam. Interior testing indicates a 33% air 67% water not 50/50 or 60/40 ration will eat more fire. Consequently at that ratio a fog tip works fine. Reachin a house in't an issue, absorbing the heat is.
<with a quarter-turn ball valve you cannot project a protective water curtain as you could from a fog nozzle>
Wet foam is wet foam, dry is dry. Wet is interior and dry is for exterior. If you want the flexibility of patterns use a fog tip.
<the unit is an aux. diesel unit for pump&roll and works well at sea level but loses the HP altitude.>
The fact it doesn't make CAFs 2 times in a row and other units around it do is due too?
01-31-1999, 12:42 AM #10tnls1Firehouse.com Guest
Thanks for the info ECBURT , we will give your suggestions a go in our next live fire evolutions. Comment about boulder was from them and hale, we know what we should be getting from a unit and will make sure it holds up to our expectations. Be safe.
02-05-1999, 11:35 PM #11DallasFirehouse.com Guest
I am interested in potentially implementing CAFS units in my department, primarily for structural firefighting. The discussion in this thread has been excellent.
I would like to know what deparments some of you are from that have been using CAFS in a structural enviornment for a while.
I would also be interested in knowing what experiences people are having with the integrated CAFS solutions that many pump manufactures are offering. In particular, althought they are very new, I would be very interested in hearing from anyone that has a Waterous Eclipse system. We have a large installed base of Waterous pumps and there is an attraction to staying with what we know.
Thanks in advance.
Montgomery County Fire and Rescue Service
Montgomery County, Maryland
02-08-1999, 03:49 PM #12tnls1Firehouse.com Guest
We have had small CAFS for over 15yrs and although these units will support a 1.5 attack line they are really intended for wildland and vehicle fires. We added a 500gpm 225 cfm unit by Magee CAFS 4-5 yrs ago and have the ability to hit the fire 4 handlines or 1 2.5 and 2 1.5 lines. We train in real structures but do not get the structure fire a week to have a real indepth background on what it does in every situation. We have done numerous fire evoulutions to simulate and remain a firm believer that CAF will put the fire out faster and with less water damage on most involved dwellings. We have used all custom built with no add ons so I can not help you there. We have Ferrarah building our next unit with the Hale System 200cfm on a FL80 4dr chassis. We talked about the Eclipse system but did not have enough background on the unit, however the players on that unit have been into CAFS for a while. Hope this helps out.
[This message has been edited by tnls1 (edited 02-08-99).]
02-09-1999, 11:32 PM #13kaFirehouse.com Guest
I used tio work with Multrip, Mcneece, George, Pelly, Stroop, McElfish, Best, etc in the county. I see no reason after owning 7 CAFS engines that it wouldn't work fine in the county.
Pierce uses Waterous pumps and uses Pnuemax's ex leader, all the CAFS rigs I've owned are Pnuemax systems on two different makes of pumps. Pneumax is not new into CAFS...has made more than all the othersalone and as the others. Simplify and reduce controls and you've got it made. It is a great force multiplier.
02-25-1999, 09:28 PM #14truck 1 engineerFirehouse.com Guest
We use CAFS on all calls, period!
[This message has been edited by truck 1 engineer (edited February 25, 1999).]
[This message has been edited by truck 1 engineer (edited February 25, 1999).]
[This message has been edited by truck 1 engineer (edited February 25, 1999).]
03-15-1999, 07:38 PM #15FirehoseFirehouse.com Guest
We are new to cafs firefighting and no one in this part of Louisiana is using cafs. for exterior, should we use a smooth tip or just straight open bore shutoff. Our plans are to use break a part select a matics but we need info as to smooth slug tips or just open bore shutoffs.
03-15-1999, 08:50 PM #16montezumafFirehouse.com Guest
Open butt, smooth bore, slug tip of fog..any work just fine for interior attack, SB's better for outside work.
03-19-1999, 11:42 AM #17tnls1Firehouse.com Guest
Thanks for the info on the nozzles . How do the automatic nozzles work with cafs? I am attempting to get a couple to experiment with and may need soome backing for the request. We have used the smooth bore and normal fog nozzles and also the "bubble cups" with satisfactory results but need to know with our larger unit on order maybe we need to go with the previous posts idea. Thanks in advance for your input.
04-08-1999, 10:20 AM #18Jim M.Firehouse.com Guest
Is is practical or cost effective to retrofit existing engines with CAFS? Any estimates of $$$ involved?
04-09-1999, 09:47 PM #19FirehoseFirehouse.com Guest
Jim, we have just ordered a new pumper with waterous eclipse CAFS. The added cost was about $40,000.retrofit will probably be more expensive.
04-21-1999, 07:35 PM #20mfdc1Firehouse.com Guest
Dallas, my dept just took delivery on a quint with the eclipse system on it,first one so they say,..so far we have found it to be a very user friendly operation and training has been going very well so far..we worked closely with waterous on this project and they could not have been more helpful..it is truly the perfect package system for CAFS
05-12-1999, 03:33 PM #21721Firehouse.com Guest
I noted that many of the posts here sound like departments purchased a CAFS pumper for structural firefighting. Just curious why most departments that select CAFS do so.
The department I am a memember of is a small volunteer department, but we chose CAFS for our last truck purchase to address the Urban Interface issue that is becoming more and more of a challange for some departments. We are located in the mountains of western NC, and more and more people are building higher up the mountain, surrounded by forest.
The roads are steep, narrow, with switch backs, etc. We spec'ed out a CAFS pumper on a 170" wheelbase International 4900 4X4 chassis. Darley 1000 GPM pump, 125cfm compressor.
Combined with short overhangs, providing 30 degree attack and departure angles, and a decent turning raduis, this truck gets many places the conventional attack pumper can't get to, and as a CAFS truck with 700 gallon booster tank, is quite effective.
That is why we took the CAFS route, just wondering why other departments chose CAFS, other thant he obvious that this is the way to fight fire, and will probably be in every station in 10 years.
We also chose to spec our CAFS engine to also handle Class B foam. There are 2 other CAFS trucks in the county, and a few in neighboring counties, but to my knowledge all are Class A foam only.
Are most CAFS class A only?
Haw Creek VFD
05-12-1999, 05:04 PM #22Jim M.Firehouse.com Guest
Miles, your truck sounds like a very effective piece of apparatus. What was the approximate cost? We are in first stage of putting spec's together for next engine and your thoughts and our are similiar.
05-12-1999, 11:28 PM #23721Firehouse.com Guest
[This message has been edited by 721 (edited May 12, 1999).]
05-19-1999, 03:36 PM #24NMFD33Firehouse.com Guest
im lost, what exactly is CAFS, i know what it stands for just not exaclty what it is and how it works...
05-19-1999, 10:38 PM #25721Firehouse.com Guest
CAFS, which stands for Compressed Air Foam System, no secret there. The most common usage is with Class-A foam, and many trucks I have seen use only Class-A. My department CAFS unit has two foam tanks and selector valve so we can also generate Class-B foam, which we use 3% AFFF for.
Start with a standard pumper, add a foam proportner to the pump, and add an air compressor that is also driven by the trucks motor.
There is the normal control to engage the pump, and additional control to engage the compressor. (we can operate without the compressor if it not needed)
The air pressure from the air compressor is automatically regulated to the discharge pressure of the pump.
In use, water is discharged via discharges that are plumbed for CAFS. The foam proportner is enabled, and the desired ratio of foam is injected into the discharge at the pump. Compressed air is also injected into the discharge at the pump. The amount of air is also regulated to control foam quality, and application.
Injecting the foam, and air into the water flow at the pump produces foam with very tiny air bubbles, and mixes it very well. This produces foam that is superior to that generated by air aisprating nozzles.
This results in lower GPM flows, usually in the 60 - 90 GPM range, vs. 125 - 150 with 1.75 lines and automatic nozzles. We also use smooth bore nozzles, that can also serve as fog nozzles.
Normal structural firefighting we use a foam application rate of 0.3% and 25 - 30% air. For structural protection in wildland fires we use a 3% foam rate with 40 - 50% air. This produces a "dry" foam that will cover a structure and protect it for an hour or longer. This allows us to go in, foam a structure, and leave before the flame front arrives. Real useful when the "pucker factor" is approaching an 8 or 9 when fires are in the crown fuels.
There have been some extensive articles on CAFS, and new tacticts on how to use it in past issues of Firehouse Magazine. Learn more about it, as it will be found in every firehouse in 10 years or less.
It is the most impressive new technology I have seen in firefighting in the 20+ years I have been involved.
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