1403 and Class A foam

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Permalink Reply by Jeff Cotner on March 19, 2008 at 6:37pm

This is a very good question that someone is going to have to address on the 1403 committee. I will be very honest with you about our use of CAFS during training fires. We don't meet the standard on the 95gpm flow. We use two attack lines, both with CAFS. Our flows are close to 65-70gpm on the 1 3/4 line and around 80-85gpm on the 2 inch line. One CAFS line is used by the attack crew and the other is ready for the fueler/lighter. A back-up line with water at 120gpm flow and a second larger back-up line is always in place and ready for use. We use CAFS all day long and have great success with its use. With the use of CAFS, it reduces the water needed during a training fire. It is not uncommon to go all day and not use more than 300-400 gallons of water. We try to train just as we would handle the real thing. We use CAFS on anything thats on fire, so therefore we use CAFS for training. As a training officer and my understanding in the use of Class "A" Foam, I'm willing to take that risk. But, we follow the 1403 standard on every other aspect of the live fire training. We don't play the heat game during training to see how hot or big we can make the fire. We only burn pallets and straw, nothing else period. Our training is focused on team work, moving the hose around inside the structure, working in a smoky environment and nozzle techniques. If we focus on the basic stuff, I think we are much better off than trying to see who can handle the most heat. Thanks Jeff

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Permalink Reply by Kristofer DeMauro on March 20, 2008 at 9:42am

Tony,

Good topic. I have mixed emotions regarding the use of CAF or class "A" foam. The use of class A foam has been an advantage to our department on wildland and grass fires. I have seen only a limited effectiveness on structural fires. Though we do not have a CAF system in our fleet, our neighboring department use them. There seems to be a continued problem with the operation and mechanisms involved in the CAF system. Any foam from my rig is from an eductor and a five-gallon pail. The eductors we use require a 200 psi inlet pressure. This causes some issues if the rig is flowing multiple lines. I like to dedicate one piece for foam only operations. Back to structures, it may that most contents in a typical residential structure are not class A anymore. With fires growing faster, and reaching flashover sooner, we need gpms to overcome the rise. I do not mean to state that the use of CAF is not effective, we have found that the initial expense for a system could be used for other equipment. I work in an environment, that for the most part, is only 600 feet from any hydrant.

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Permalink Reply by Tony Piontek on March 20, 2008 at 10:26am

Backing up the CAFS lines would put you in accordance with 1403, and that's how I've handled it in the past as well. I agree you HAVE TO train with what you're using. Sounds like you have your feet solidly planted in 1403, great job! I'd like to hear more from you, if you could comment on the other threads it'd be appreciated. Train like the real thing...I like it...what a concept!!!

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Permalink Reply by Tony Piontek on March 20, 2008 at 10:31am

I have some of the same concerns...a false sense of security in things I do not know much about. And I find that most departments with CAFS cannot explain to me any more than I already know...are the salesmen/manufacturers not training them? Seems like an overreliance on a technology to me, but I'd like to know I have gpms behind me, not some foam concentrate. Your point on contents within a structure is a valid point as well. We're walking into petroleum storage facilities, not residences. Nice thread!

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Permalink Reply by Jay Robinson on March 21, 2008 at 5:15pm

Forgive my ignorance guys. Seattle is new to the CAFS arena. I know that we have a few new engines with CAFS capabilities but I'm not aware of any training that has taken place. Is there an issue with GPM and CAFS systems? We typically pump 100 psi at the tip. For AFFF we have 120 gpm eductors with a similar 200 psi inlet pressure. My question is, can you overdrive the CAF system resulting in poor foam concentration? Do we need to gate down? As for live fire, our rigs at the state academy do not have the capability. We concentrate on teaching the recruits to monitor their heat conditions and be able to scientificaly justify their entrance into a space based upon the size (conversion space) of the room, size of fire involved (IOWA verses NFA) and heat levels (pre-flashover conditions). As you know pallets and hay can get us close to normal fire loading of 8,000 btu's per lb per sq. ft. but until they learn the fire chemistry and behavior as well as the proper water application, there is no reason to over tax them with CAF systems.

Thanks in advance for your input,

Jrob

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Permalink Reply by Tony Piontek on March 21, 2008 at 5:38pm

The standard requires a MINIMUM of 95 gpm...some of the smaller handlines will not have this due to the large proportions of foam and air. The foam will be good, but the cooloing effects of the water will not be there. I cannot get an answer from Ansul (foam producer) or Hale (pumps) as to how this would equate...hence it does not meet the standard. AFFF or class B foam is 94-99% water, vapor barrier AND water cooling effects. CAFS do not have these properties, or at least, no one can tell me this. It does work on fire, BIG fire, I've seen it. According to the standard, there is no exception to the 95 gpm flow rate. And to me, this is a bit low in todays structures, even if we stick with pallets and hay. We don't use it on our handlines, we've increased to 150gpm minimums, why is the training standard so low? If anyone can shed some light on the CAFS question, PLEASE chime in.

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Permalink Reply by Kristofer DeMauro on March 22, 2008 at 12:45pm

JRob,

I believe that one issue with the mistery that is CAFS is that we (Fire Service) try to use it like we would Class A or AFFF. It (CAFS) is not designed to work like that. A selling point that some sales people have used is the reduce water needs, thus making it great for rural operations. Foam does not convert to steam. It can only seperate the oxygen from the fire. No cooling, no turning to steam, absorbing the heat energy. I am only speaking from my experiences, both in training and working real fires. If you can help us learn about CAFS please do. Next time a CAFS rig is at the trainig ground tell us about it. Maybe we , more likely me, is missing something.

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Permalink Reply by Mark Cummins on July 15, 2009 at 2:46pm

CAFS makes very tiny bubbles. These bubbles are made with thin films of wet water. They absorb heat and reach steam temperature twenty times faster than a solid water droplet. Bubbles don't burn, but they can capture CO2 by chemical action with the surfactants in the foaming agents. The controled production of steam and CO2 with CAFS flows extinguishes more fire that twenty times more water. That's why you see water running down the street when you don't use CAFS.
Your problem with CAFS will be how to run your big water pump at slow enough rpm to not burn it up with such small water flows. (50 gpm and LESS) You also need to train how to put your finger in the CAFS stream to create a fan pattern for interior fire fighting. The straight stream needs to be unrestricted from the reducer tips, Let the bubbles do their work. I have never burned a bubble.

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Permalink Reply by Brian Arnold on July 15, 2009 at 3:29pm

Mark,
It still doesn't answer Tony's original question of how you meet the NFPA 1403 standard of providing a min. of 95gpm. Do you back up the CAFS with a line that flows 95gpm or more? If you have nothing but CAFS lines on the ground during Live Fire Training you have not met the standard. I understand how it works but it still doesn't meet the standard.

In our limited CAFS training, we back it up with a 1 3/4" SB line and generally have a biff line with the firestarters for a little added protection. Unfortunately, like Kris posted earlier not many departments around us run with CAFS and rely on class A foams in the 5 gallon buckets and eductors.

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Permalink Reply by Mark Cummins on July 15, 2009 at 6:19pm

Brian, thanks for the comments about my post.

The commitees that set the standards are trying to do the best they can with the technical information that they have. But there's the problem, they can't get the information about CAFS that will please everyone on the comitees.

The most effective applications for the CAFS technology stands to hurt the water pump manufacturers profits drastically. Some of them know good and well that CAFS should be measured by the foam volume being discharged at the end of the hose rather than the amount of water the pump is supplying at the manifold. The National Institute Of Standards and Technology published a very complimentary report comparing a gallon of water to a gallon of CAFS foam and showed the CAFS gallon to be much more effective than the gallon of water applied to all types of there test fires.

Therefore thew standard should state that the CAFS flow of a 200 cfm CAFS would be 1,496 gpm when converted to gallons of foam being discharged onto the fire. I realize NFPA will probably never change this standard because they can't understand or accept the difference between foam and water.

There might need to be a change in who uses the CAFS and how they create a new standard for it.
.

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Permalink Reply by Brian Arnold on July 17, 2009 at 9:02am

Mark,

Thank you, that info. is helpful.

Brian

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