The agent works by interrupting the chain reaction that keeps the fire burning. The extinguisher is equipped with a pressure gauge which indicates if the extinguisher is charged. The production of the extinguishing agent is being phased out. The halon extinguishers on campus are being phased out as they are used and are typically located in labs handling chemicals and computer installations. Dry powder is also available in 50 lb. pails for dispensing on a fire with a shovel or scoop.
Dry powder is used for Class D combustible metal fires.
Sodium chloride-based dry powder may be used on combustible metals and metal alloys such as magnesium, sodium, potassium, sodium potassium alloy, uranium, and powdered aluminum. They are sodium chloride based. The range is 3-10 feet and the discharge time is 28 seconds.