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Fire Related Products

Compressed Air Foam Systems -- What are Compressed Air Foam Sytems?

Compressed Air Foam Systems (CAFS) are a method of enhancing the fire fighting effectiveness of water. Compressed Air Foam Systems do this by injecting pressurized air and foam concentrate into the water stream generated by a fire pump. This creates tiny bubbles, pockets of air surrounded by water. These bubbles are small, uniform and dense and have the advantage of being much longer lasting than bubbles created without pressurized air. Foam composition can be varied by adjusting the amount of water added to the mix, resulting in foams that can be used for different purposes. Very little foam concentrate is required to form the bubbles with this method. 0.4 of 1% is common for Class A Foam., as opposed to other methods, which use far more foam concentrate.

Water is the primary fire fighting element. Normal fire fighting methods use water to reduce heat below the temperature required for sustained combustion. Water does this by absorbing heat and releasing it as steam. But it can be difficult to maintain enough water at the point needed to put out a fire. Water naturally tends to be repelled by heat. Consider what happens when you add water to a hot frying pan. The water forms beads (due to surface tension) and moves away from the hot spot. In fire fighting relatively large streams of water or pressure must be applied to get enough water into location to put out the fire. Much more water has to be used than is actually needed. Most of it (up to 95%) flows away, carrying debris and chemicals from the fire with subsequent hazard and damage to the surrounding environment. Compressed Air Foam tends to stick to surfaces, even ceilings. Thus the water will stay where it is needed, absorb more heat (because of the bubbles) and do less damage due to runoff. The use of Compressed Air Foam Systems (CAFS) is often characterized by very rapid knockdown of a fire, especially in structures.

Compressed Air Foam Systems (CAFS) reduce the surface tension of the water by means of the foam concentrate used. Less water is needed to put out the fire. Because Compressed Air Foam Systems (CAFS) can vary the consistency of the bubbles created, it can be used in different ways. A foam with less water (dry foam) can have the consistency of shaving cream and be used as an insulating blanket, to stop fire spreading to adjoining structures. A foam with more water will penetrate combustibles better (I.e. soaking into thick layers of grass or brush, garbage or silage).  A Compressed Air Foam System can generate a foam blanket that will isolate fire or potential fuel from oxygen, thus putting the fire out.