WHAT IS CAF (Compressed Air Foam)?

Basically a combination of water, foam concentrate and compressed air - makes water a more efficient and effective firefighting agent.

Class A Foam Concentrate, has one main function in CAF and several other benefits when mixed with water. The main need for the concentrate in CAF is to allow the air and the water to mix. Without the concentrate, air and water cannot mix together.  

The other benefits of mixing the concentrate with water:

• Reduces the surface tension of the water allowing the water to flow freely so it will soak into combustible materials.
• Makes the water cling to carbon materials (ordinary combustibles) - this prevents the rapid run off and allows water to soak into wood.
• This affinity to carbon also causes the foam bubbles to attract carbon bi-products of fire (smoke) reducing the black cloud production over a fire. This also results in improved visibility for both firefighters and trapped victims within a burning structure.

Why the compressed air? Water has the ability to absorb a lot of heat (9300 btu's/lb). However, as water is applied to a fire in drops, only the outer portion of each drop absorbs the heat. A large amount of the water passes by or through the fire, resulting in water damage. By pumping air into the water, each drop is blown up to a bubble forcing the entire drop to the exposed surface. This expanded "surface-to-mass ratio" (SMR) allows the entire drop to instantly absorb its full capacity of heat. No excess water passes through the fire - the fire goes out much faster and water damage is virtually eliminated.

What is the actual affect? By fighting fire with CAF, fully involved house fires have actually been extinguished in as little as 30 seconds using as little as 40 gallons of water. Most fires could actually be extinguished with small total amounts of water if the water could be applied effective enough for all of the initially applied drops to absorb the heat. Since water by itself is not applied effective enough form, large volumes are required, resulting in high run off and water damage. CAF application is effective enough to result in immediate heat absorption, thus resulting in the lower total water usage and damage.

Does it actually work? Unequivocally - YES!,

How does it work? As mentioned above, CAF knocks out fire faster due mainly to the increased Surface-to-Mass Ratio (SMR). Expanding water drops into bubbles increases the SMR. Bubble expansion can be low, medium or high. Aspirating nozzles will expand water into higher SMR bubbles. The benefit to using CAF over aspirating nozzles is the long distant, high energy stream for reach; combined with the expansion into small uniform bubbles that provide a stronger, longer lasting bubble than can be produced by aspirated bubbles.

Foam solution is liquid drops; the SMR is the same as water. The benefit to Foam Solution over water is the decreased surface tension and it will adhere to carbon better than water. Most fog nozzles will break the Foam Solution in to smaller drops, increasing the SMR some what above water, however, Foam Solution is still in drop form and can pass through the fire wasting the water and causing damage. Foam solution also does not have the vertical holding capability to coat walls. Foal Solution will immediately run off of vertical surfaces. CAF is superior to Foam Solution in that the compressed air expands the water to its maximum SMR, allowing it to immediately absorb heat and practically eliminate water damage. With the strong uniform bubbles, CAF can also cling to vertical surfaces.