Tupelo Fire Equipment is more than a company that just "wants to make money" from Emergency Services, we want to make sure you are as informed as possible. We want to help you make the best decisions for the needs of your staff. This page is solely for information purposes and it not intended to "sell" one product or brand over the other. Please see below for some of our more commonly asked questions on equipment.

Foam

What is the difference between Class A and Class B foam?

Class A foam is for Class A materias (paper, wood, brush, and general combustables). Class B foam is for chemical fires, gasoline, oil, curde, jet fuel, etc. There are many types of Class B foams. The Fire Department must be very careful to use the correct Class B foam for the petrochemical that is involved.

Can I use a standard eductor with Class A Foam?

Sure! But please be aware that it will release a LOT more foam than is needed. Class A foams are typically use at percentages of less than 1%. If a standard eductor (3% - 6%) is used, you will use 3 to 6 times moew foam which will not work any better and will cost more. Modifications are currently available from some eductor manufacturers that allow for a fixed 0.5% setting. As long as all requirements are met for use of the eductor as outlined in the manufacturer's information, the use for Class A foam can be accomplished.

Are Class A foams the same as wetting agents?

No, Class A foams are similar to wetting agents, but are true foam concentrates. They may be proportioned and applied in aspirating form to create a thick, white blanket (think snow), or in unaspirated form, as a water wetting and penetrating agent. By the choice of proporation ratio and nozzle model, a wide variety of foam consistancies may be achieved for different applications.

Since Class A foams are true foam concentrate and have received environmental approvals, could we use these foams as training forms for our firefighters instead of the expensive Class B foams we now use?

As long as no live fire training is involved, when mixed in ratios of 1% or less, the Class A concentrates offer a very cost effective product to familiarize firefighters with foam injection systems, application equipment and vapor suppression extinguishment techniques.

Our department has no water supply problems. Why would be want to use Class A foam agents on our everyday structural attacks?

Use of Class A foam concentrates allows you one more tool to accomplish your job more safely and quickly. Determined by the National Institute of Standards and Technology Center for Fire Research in Maryland, and the Bureau of Land Management Foam Projects, Class A foaming agents, by modifying the surface tension of the water, increase the solution's ability to penetrate and suppress fire by 3 to 5 times. Aerated foam will cling to and blanket Class A fuels, insulate exposures from radient heat and provide water penetration on hard to reach deep seated fire.

Is the injection ratio the same for Class A foams as for AFFF and protein type foams of 3% and 6%?

No. Mixing ratios with Class A foams may be varied depending on the method of application or specific need, but typically the Class A foam concentrates mix at a rate of 0.3% to 0.6%. It is quickly noted that this is about 1/10 the rate at which Class B type foams must not be applied. This fact shows that the logistics and economics of applying these concentrates is a very cost and manpower effective tool. Unlike the AFFF and protein type foams, which have a specific application injection ratio, the Class A foam may be varied depending on the rate desired.

Should we concerned about corrision in tanks, pumps nozzles or couplings?

There are many Class A foams and wetting agents on the market today. Though most act as detergents in water systems by cleaning metal and breaking down lubricants, remember to use only Class A concentrates that have received final approval from the US Forest Service. These approvals not only address environmental and safety concerns, but determine the acceptable levels of corrosivity. The U.S.F.S. approves only those concentrates which have acceptability low corrosion rates on mild steel, brass and aluminum.

The CAFS and WEPS are used occasionally in discussion of Class A foaming agents. What do these terms refer to?

CAFS (compressed air foam systems) and WEPS (water expansion pumping systems) are terms used to describe high energy systems of producing greatly aerated foam. A typical system includes not only a foam injection system and water pumping system, but also in an air compressor. When mixed in common ratios of 1 cfm of air to 1 gpm of water, these systems can offer increased reach from lower water flows, and a more "shaving cream" type of consistancy foam for extended exposure protection and moisture holding ability of Class A fuels. The Bureau of Land Managment, Boise Interagency Fire Center continues to do extensive research of CAFS units for both wildland and structural attach applications and can offer a wealth of information on design and implementation of a CAFS.

What are the possible benefits from the regular use of Class A foams?

In the wildland, burning brush and grass not only are more quickly contained, but the overhaul and mop up time is dramatically reduced. Structurally, faster knockdown times and less water damage are continually being documented by departments all over North America. Tire fires, once potential environmental disasters, can now be contained more easilty and more quickly smothered with less hazardous waste water runoff. Other deep seated fires dreaded by fire agencies such as peat moss, dump and hay/barn fires are being quickly and safety brought under control. The us and application of Class A foams is an extremely cost effective tool to help fire suppression professionals deal with ever increasing fire loads and related hazards.

Can we mix Class A and Class B foams in the same tank?

Only if you want a big ole' mess. The alcohol in the Class A (used to give it a lower freeze point) mixes with the polymers in the Class B foam and forms a nasty, nasty glop that has to be cleaned for the tank manually.