Foam 8
Foam 8 : The collection of a mass of bubbles which are formed by forcing air into a solution of water and foam concentrate by means of suitably designed equipment or by cascading it through the air at a high velocity. Common terms and definitions associated with foam include: Aspirate: To draw in air by suction. The aspirating nozzle draws air into the nozzle to mix with foam solution. Aspirating Nozzle: A foam generating device that mixes air at atmospheric pressure with foam solution in a nozzle chamber. Batch Mix (Batching): Manually adding one ingredient to another to develop the final product. Batching can involve a powder and a liquid or two liquids. For foams it is the process of manually pouring foam concentrate into water to make a foam solution. Foam is produced when the solution is pumped down a hose and out an aspirating nozzle. For fire retardants it is the process of adding powder to a measured amount of water and mechanically agitating it to produce fire retardant. Batch Mixer: The container in which batching is done. In retardant mixing operations, it is a tank, usually 1,000 gallons in which powdered retardant and water are mixed together by mechanical means to produce the final product. Class A Foam: Foam intended for use on woody fuels. Made from hydrocarbon-based surfactants possessing excellent wetting properties and is biodegradable. Class B Foam: Foam designed for use on flammable liquid fires. Combination Nozzle: Also called an "adjustable fog nozzle". Used for applying water, wet water, or foam solution as either a solid stream or a fixed spray pattern. Compressed Air Foam System (CAFS): A foam system which combines air under pressure with foam solution to create foam in the hose. "Dripping" Foam: Characteristics: The bubbles of "DRIPPING" foams are mostly spherical. There is less separation of bubbles by the solution than wet foam. Some of the bubbles walls may be touching. Dripping foams have medium to fast drainage rates. Syn: Fluid Foam. Dry Foam: Characteristics: The bubbles of "dry" foams are polyhedral in shape. The bubble walls are very thin with only small amounts of solution between the bubbles. These types of foams have very slow drainage rates. Eductor: A proportioning device using vacuum created by a liquid moving through a hose line to draw another liquid into the stream. In foam operations, foam concentrate is educted into the main water stream through a venturi. The venturi create a vacuum in the water stream causing foam concentrate to be drawn into the stream. Educting can take place on the suction or discharge side of the pump. When using an eductor, mixing takes place either when the solution passes through the pump or in the turbulence as the solution travels down the hose line
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