AB FIRE EXTINGUISHER INFORMATION
AB fire extinguishers are applicable to Class A Fires and Class B Fires.
Class A fires include ordinary materials like burning paper, lumber, cardboard, plastics etc. Class B fires include flammable or combustible liquids such as gasoline, kerosene, and common organic solvents used in the laboratory. The units shown here are good for handling either kind of those fire threat.
However, they should NOT be used on energized electrical equipment (Class C) or burning metals (Class D) fires.
What the A B C ratings mean on AB Fire Extinguishers
Fire extinguishers with a Class A rating are effective against fires involving paper, wood, textiles, and plastics. The primary chemical used to fight these fires is monoammonium phosphate, because of its ability to smother fires in these types of materials.
Fire extinguishers with a Class B rating are effective against flammable liquid fires. These can be fires where cooking liquids, oil, gasoline, kerosene, or paint have become ignited. Two commonly used chemicals are effective in fighting these types of fires. Monoammonium phosphate effectively smothers the fire, while sodium bicarbonate induces a chemical reaction which extinguishes the fire.
“C” ELECTRICAL EQUIPMENT
Fire extinguishers with a Class C rating are suitable for fires in “live” electrical equipment. Both monoammonium phosphate and sodium bicarbonate are commonly used to fight this type of fire because of their nonconductive properties.