Phos-Chek fire retardants are manufactured as dry powders or as concentrated liquids and diluted with water prior to use. The retardant is applied ahead of wildfires to homes and vegetation by ground crews and aerial firefighting units, either fixed-wing or rotary-wing aircraft.
It is currently produced as several colors, including an off-white color, red iron oxide, and a fugitive mixture that is colored red when dispersed but gradually fades to an earth-tone when exposed to sunlight. The red color aids aircrews in targeting drops of retardant.
Some of the main components of Phos-Chek retardants include ammonium polyphosphate, diammonium phosphate, diammonium sulfate, monoammonium phosphate, attapulgus clay, guar gum (or a derivative of guar gum), and trade secret performance additives. Fire retardants are manufactured as several different formulations with varying proportions of the above components.
The phosphate and sulfate salts act as fire retardants and prevent combustion of cellulosic materials. They also act as a fertilizer once the fire danger has passed. Guar gum and clay are thickening agents to prevent dispersal of the retardant after it is dropped from the plane. Other ingredients include corrosion inhibitors and flow conditioners.
Class A foam
The first Phos-Chek retardant product was available in 1962. The Phos-Chek brand belonged to the Monsanto Company until 1998, when ownership was transferred to Solutia Inc. In 2000, Astaris LLC acquired the Phos-Chek name. In November 2005, Astaris LLC was acquired by Israel Chemicals Ltd. (ICL), and the Phos-Chek brand was renamed "Phos-Chek Fire Safety Group" and assigned to the Performance Products division of ICL (ICL PPLP).
The Airbase Service Center, located in Post Falls, Idaho is the headquarters for all North America. This 30,000 square foot facility supports all bulk bases (equipment and product support to agency operated bases), SEAT bases (equipment and product support for Single Engine Air Tanker Bases), and Portable Base Operations (mobile rotor and fixed-wing bases). Various equipment maintenance and base rebuilds are performed from this location. Fabrication of liquid concentrate tanks, batch mixers, Hopper Units, and various other equipment is performed from this location.
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