Dry powder fire extinguisher (Class A ,B ,C ,D)
Useful on most alkali metals including sodium and potassium, and other metals including magnesium, titanium, aluminum, and zirconium. The effect of the powder is to “knock down” the flames and it is best for fires involving flammable liquids or gases. Plastic melts to form an oxygen-excluding crust over the metal, and the salt dissipates heat. Standard powders work well only on burning liquids but the dry powder is multi purpose. The dry powder extinguisher is most commonly used and has a range of 1 – 5 m. and the discharge time is about 28 seconds. The main advantage is that it can be used for almost all classes of fires including A , B , C , D.