| AR-AFFF [message #306096] |
Mon, 29 August 2016 01:44  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I have been advocating for years that fire extinguishers, especially automatic deployment ones in gasoline powered motorhomes should be AR-AFFF (Alcohol Resistant - Aqueous Film Forming Foam)
I bit of history here. My coach caught fire about 11 years ago in my driveway and I was able to put it out after much effort with several types of fire extinguishers. It was then I and several others went looking for the best solution for gasoline fed vehicle fires especially in GMCs. We looked at primarily dry powder, water, Co2 , halon (and it's new substitutes,) and Foam (AFFF). Each of these types have some disadvantage or another over the others which I will not list at this time. It came out that the best overall solution for a GMC fire was AFFF (foam) types.
About that time Kidde was closing out their 2 liter portable AFFF extinguisher line because of poor sales numbers. They did not market them correctly. They just wholesaled them to places like Home Depot and Menards where they sat on the shelf next to cheaper Dry Powder types that looked same but were $20.00 cheaper. So when Kidde decided to drop the 2 liter size I and a few other GMCers, primarily in the midwest, bought up everyone one we could find at discounyted prices. I personally bought over 60 of them and resold them to GMCers at cost for use in their motor homes.
These AFFF extinguishers were good but could have been better with a minor change or two to fit our unique motorhome environment.
1. The biggest problem is that AFFF does not perform well on fires with polar solvents (ethanol). AFFF will not perform well on gasoline with more than 10% ethanol.
2. The second problem is that AFFF's primary component is water (usually 97%) and will freeze at 32 degrees F. That means that an AFFF extinguisher needs to be removed from the coach if temperatures will go below 32 F. where the coach is stored. This becomes a larger problem in an installation where the extinguisher is a remote bottle with a line running to a remote automatic sprinkler head. While freezing will not physically hurt the storage bottle, it can crack or split the tube between the bottle and sprinkler or sprinkler head itself.
Fortunately there are fixes for both of these problems.
For item 1: The industry has developed an Alcohol Resistant AFFF to address the problems with item 1. There are many manufacturers of AR-AFFF. The one we use at our airport is ANSULITE 3% 6% made by Ansul. This stuff is mixed at the 3% level for all fires not involving on road E-10 gasoline (no polar solvents (alcohol)). The same same stuff is mixed at 6% for on road gasoline vehicle fires. It is assumed these days on gasoline vehicle fire call that all on road vehicles are using E-10 fuel. Our trucks mix this stuff on the fly and can easily change from one to the other mixture.
Why not just use 6% all the time? Well, thank the Feds for that, FAA regulations, written before E-10 became popular, requires us to use 3% AFFF on aircraft fires. Also aircraft gasoline never contains ethanol by FAA regulation. Since our trucks are used both on and off airport, we need and use the mix on the fly system.
On Item 2:
The industry has developed several "Freeze Protected" versions of AFFF and AR-AFFF. So by filling your extinguishers or buying new extinguishers with Freeze Protected Alcohol Resistant AFFF you will have these above short comings covered.
The Ansul product mentioned here can be seen here:
https://www.ansul.com/en/us/DocMedia/F-2003282.pdf
Some other products on the market will go even lower than 0 degrees F but at least this one will take you down to 0 F., is readily available and should cover most of us.
Those original Kidde 2 liter extinguishers that we bought were AFFF. Every year I recommended to GMCers that they be removed from their coaches when the temperatures approached 32F. Well today after 10 years or so I re-read the label and guess what? They are freeze protected down to 10 C or 14 F. It turns out that Kidde charged them with 3% AFFF, 25% ethylene glycol antifreeze, and 72% pure water). So this year I will not send out an alert until the forecast temp will be below 15 F.
Also contrary to popular belief, while freezing an AFFF extinguisher will not hurt the extinguisher, according to Ansul it will cause separation of the AFFF concentrate from the water (just like what happens when freezing salt water). Ansul says in the case of freezing, the extinguisher needs to be depressurized and the AFFF or AR-AFFF mechanically mixed again.
So in conclusion. I would suggest that if you are buying new fire extinguishers especially automatic deployment types that you buy Freeze Protected AR-AFFF charged ones unless your coach never leaves Florida, or Southern Arizona in the winter.
We can discuss the merits of Halon and it's replacements, or CO2, or Dry Chem in another posting. I also left out Purple K types which we should never need.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: AR-AFFF [message #306109 is a reply to message #306096] |
Mon, 29 August 2016 11:14  |
Jon payne
Messages: 495
Registered: May 2008
Karma: 1
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Senior Member |
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Thanks Ken for the information! Very helpful. Where can you get portable extinguishers?
Jon
Jon Payne
76 Palm Beach
Westfield,IN
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| Re: AR-AFFF [message #306124 is a reply to message #306109] |
Mon, 29 August 2016 13:48 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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That part I have not investigated in several years, so I have no specific brand and model recommendations. The ones we bought from Kidde were dropped from the product line years ago. They do make larger ones. If you have one you can still use it or have it recharged. They met the D.O.T. 2-Q standards which has to do with bursting strength. These Kidde ones are charged to 195 PSI. Any of the name brands (Ansul, Amerex, Kidde, etc.) should work well.
Jim K. and Jim Bounds both sell several RV type extinguishers for engine, onan, and refrigerator areas under Jim B's brand name of Firefight or Firefight Marine. I "think" that their product line is AFFF, but not AR-AFFF, and are not freeze protected. They also have a small automatic deployment halon one that would be good in the refrigerator area only. I normally would not recommend halon in a GMC, but in the refrigerator area a halon or halon substitute automatic deployment one would be a good fit.
You will have to check with them to see what they are charged with for sure as I have no personal experience with them. At least you know what questions to ask them or any other vendor. I feel that AR-AFFF and "Freeze Protected" for permanently mounted ones are are important to me. I have seen the difference between AR-AFFF and AFFF on E-10 fires when they were doing fire training at my local airport.
I have some concentrate Ansulite AR-AFFF 6% here but not the freeze protected stuff. When I need one charged I supply the mix and a friend at the local FD will charge it for me to 195 PSI. I do not have the equipment necessary to do it.
Different extinguishers use different propellants and pressures. The Kidde ones we bought are compressed air or nitrogen to 195 PSI.
I'm sorry I'm not much help but as least you now know the questions to ask. Many vendors are very tight lipped about what they are selling and most of the general public will not ask the appropriate questions or understand the labels on what they are buying.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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