Thread: What type of foam for CAFS?
10-02-2003, 09:14 PM #1
- Join Date
- Feb 1999
- Pittsburgh, PA USA
What type of foam for CAFS?
Placing an apparatus in service with a CAFS system. Looking for suggestions on type/brand of foam to use for this dual A/B system.
Looking for advice based on cost/benifit factors for different brands/types.
I understand that there are "universal type" foams out there, but are they worth the cost. It would be nice to have 60 gallons of agent for use on either A or B fires, but is it cost efficient. We will have a 2 tank system 30 gallons of agent each. Is it best to have seperate class A and B, or go for the universal foam.
What brand have you had success with in CAFS applications.
Thanks For The Help.
10-03-2003, 08:16 AM #2
- Join Date
- Jun 2001
- Baltimore, MD
The key question is what foam have been approved for use with your CAFS system. I know manufactures test foams thought the foam pump to make sure their ar no issues with it. They do not recommend a specific foam but let you know what foams have been tested.
10-03-2003, 11:23 AM #3
- Join Date
- Oct 2003
Foam concentrates for CAFS
I will not be promoting any concentrate over another. I would like to offer you some information based on my experience with foam and CAF for the past 15 years.
The first thing you must consider when choosing the type of foam concentrate to use with your new system is to analyze the potential hazards your department might face.
Are your hazards primarily Class A - Vehicle fires, grass fires, and building fires. Or do you have a significant Class B hazard - bulk fuel storage, petrochemical or other manufacturing facilities?
If after you evaluate your hazards, you determine that the majority of your incidents will involve Class A fuels, and a slight chance of encountering a minor Class B spill or non-fuel in depth B fire, look at the Data sheet for Ansul’s Silvex or National Foam’s Knockdown. Both of these data sheet do “rate” these class A concentrate for use on minor B fires.
Check the websites for Ansul and National Foam. You can download the data sheets for their most popular foam concentrates. I am most familiar with these two manufacturers. But there are many foam concentrate manufacturers out there. The bottom line comes down to the cost to use the stuff, and where you can purchase replacement when you do use it. A 3x6 may cost the same as a 3x3, but on a polar solvent fire you would use twice as much of the 3x6 as you would with the 3x3.
Be very careful on the “universal” foams out there. Some of these manufacturers state claims that their concentrates are UL listed. But ask them if they have passed the UL 162 test for Class B foam concentrates. If you look what a foam concentrate has to do to be effective on a particular type of fire. The chemistry is completely different. A class A foam needs to make the water bubbles carbon ATRACTIVE. Meaning the class A foam will stick to a class A fuel to allow the water in the bubble to be absorbed into the fuel to cool. A class B foam bubble needs to be carbon shedding, meaning the bubbles need to float on top of the fuel to provide the vapor sealing barrier.
Next, after you have all of the above information, you need to look at the foam proportioner you have in your system, and the GPM of foam concentrate the proportioner can deliver. If you proportioner can only deliver 2.5 or 5.0 gpm of concentrate, that would equate to 83 - 166 GPM of foam solution if you would use a 3% concentrate. If your B hazards are hydrocarbons and very little polar, many manufacturers make good 1% AFFF. If you use this type of concentrate, you can increase your solution flow by a factor of 3 to 250 - 500 GPM respectively.
Lastly, look at the information supplied with your foam proportioner. All of the proportioner manufacturers list the brands and types of concentrate their respective systems will proportion accurately.
Good Luck, and let me know if you need any additional information.
10-08-2003, 11:40 PM #4
- Join Date
- Jan 2001
- Madison, NJ USA
Been using CAFS successfully since 1998. We are using Phos-Chek WD-881 Class A foam. It has worked well for us and smells good too. Whatever class A foam you use I would suggest that you verify that it is on the US Forestry’s qualified foam list. http://www.fs.fed.us/rm/fire/downloa...pl_current.pdf The list contains A foams that are environmentally friendly. I would not use any foam that is not on the list, otherwise it could be a "haz-mat" when applied. Class B foam when applied is a haz-mat and must be cleaned up. I'm skeptical of "universal" foams. In my opinion it is either A or B.
As far a B foams go, my department does not have any. We have a dual tank system. Keep A foam in each. We used to carry a 1x3 AR-AFF in the 30 gallon cell. If you do the math 30 gallons at 3% dose not do much in the way of good gpm flow, even with a 5 gpm foam pump. We carry 20 gallons of class A foam in the other cell. As you probably already know, Class A and Class B foam concentrates hate each other. When they mix together they transform to "snot" then to "jello" and then finally turn solid. It can become your worst nightmare if they are ever mixed together.
My department had a bad experience with the mixing of A and B foams. What happened to us was someone turned the manual foam selector valve from A to B and back to A. We normally keep it turned to the A cell since 99.9% of the fire we fight are A foam applications. What happened next was that momentary turning of the valve caused a small amount B foam to mix with A foam. The jello like stuff worked its way through the foam plumbing and got caught in the strainer just before entering the FoamPro pump. Of course it happened on the fireground. It plugged the strainer solid and no foam or CAFS was flowed. No firefighters were hurt and we went right to water only operations. The Chief and officers looked at how many times in the past 40 years we actually used or needed to use class B foam. Given the fact that class A foam applied with CAFS will extinguish a class B fire, due to the small, tight, uniform bubble structure that CAFS produces. It was then decided not carry or purchase any more class B foam.
Hope this helps, and remember CAFS is a tool. You must train with it.
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