Purple-K is a dry chemical fire suppression agent used in some dry powder fire extinguishers. It is the most effective dry chemical in fighting class B (flammable liquid) fires, and can be used against some class C (energized electrical equipment) fires. It is about 4-5 times more effective against class B fires than carbon dioxide, and more than twice than sodium bicarbonate. Some fire extinguishers are capable of operation in temperatures down to -54 °C or up to +49 °C. It smothers the fire.

Purple-K is commonly used in oil refineries, airport ramps, service stations, military facilities, and other places where flammable liquids are handled.

Purple-K powder is odorless, free-flowing, floating on most liquids, non-abrasive, and does not wet with water. It has violet color, to distinguish it from other dry agents. Its principial component is potassium bicarbonate (78-82 weight %), with addition of sodium bicarbonate (12-15%), mica (1-3%), Fuller's earth (1-3%), amorphous silica (0.2-1%), and is made hydrophobic by methyl hydrogen polysiloxane (0.2-1%).

Purple-K is used in many forms, from small handheld fire extinguishers to large mobile and stationary units, including fixed-nozzle piping systems.

Cleanup of spent agent can be achieved easily by a vacuum cleaner or a broomstick.

Purple-K is non-toxic. Ingestion of large amount can cause alkalosis. The content of silica causes its carcinogenity. In high temperatures it decomposes to carbon dioxide and potassium oxide. It is corrosive.

Purple-K should never be mixed with phosphate-based fire suppression agents (ABC type dry chemicals), as the resulting chemical reaction will destroy its efficiency.

Purple-K is also a brand of dietary supplement creatine.

Variocrom Magic Purple K is a pigment based on gamma-iron(III) oxides and silica, used in plastic industry.

Fire suppression agents