Types of Fire Extinguishers
Class D Extinguishers: Class D fire portable fire extinguishers are required in those combustible metal working areas where combustible metal powders, flakes, shavings (magnesium, titanium, sodium, and potassium) or similarly products are generated at least once every two weeks. The travel distance from the combustible metal working area to any extinguishing agent must be 75 feet (22.9 m) or less. Class D extinguishers typically lack a numerical rating and are not designated for multi-purpose use on various fire types.
- Dry powder extinguishing agent: Type D extinguishers typically contain a dry powder agent specifically formulated to smother and suppress fires involving combustible metals.
- Non-conductive: The extinguishing agent is non-conductive, ensuring safe application on energized electrical equipment.
- Thermal insulation: Type D extinguishers are designed to provide thermal insulation to prevent reignition of metal fires.
- Specialized nozzle: The extinguisher is equipped with a specialized nozzle to effectively dispense the dry powder agent onto the fire.
- Class D fire rating: These extinguishers are labeled with a Class D fire rating, indicating their suitability for use on combustible metal fires.
Type K Extinguishers: Due to the higher heating rates of vegetable oils in commercial cooking appliances NFPA 10, Portable Fire Extinguishers, now includes a Class K rating for kitchen fires extinguishers which are now required to be installed in all applicable kitchens. Once a fire starts in a deep fryer, it cannot always be extinguished by traditional range hoods or Class B extinguishers. Travel distance to a Class K extinguisher must not exceed 30 feet.
- Do not attempt to use a Class A extinguisher containing water or CO2 on a deep fat fryer fire. An explosive type reaction may result.
- Place a placard near the Class K fire extinguisher which states: "In case of appliance fire, use this extinguisher only after the fixed fire suppression system has been actuated". Class K fire extinguishers are only intended to be used after the activation of a built-in hood suppression system. If no commercial cooking system hood and fire suppression system exists, Class K extinguishers are not required.
- Extinguishing agents in many Class K extinguishers are electrically conductive and should only be used after electrical power to the kitchen appliance has been shut off. Class K extinguishers use a variety of agents. Potassium bicarbonate is used in some Class K dry chemical extinguishers, and there are also Class K wet chemical extinguishers which spray a fine mist.
- Install a 2-A water-type extinguisher or 6L wet chemical fire extinguisher for solid fuel cooking appliances with fire boxes.
- Inspect, test and maintain Class K fire extinguishers yearly.
- These extinguishers will be found in commercial cooking operations such as restaurants, cafeterias, and other locations where food would be served.
Type AB and ABC Extinguishers: Dry chemical extinguishers put out fires by coating the fuel with a thin layer of fire retardant powder, separating the fuel from the oxygen. The powder also works to interrupt the chemical reaction, which makes these extinguishers extremely effective. Carbon dioxide (CO2) extinguishers are designed for Class B and C (flammable liquid and electrical) fires only.
- Multi-purpose: Effective against Class A, B, and C fires (wood, flammable liquids, and electrical fires).
- Extinguishing Agents: Typically contain dry chemical agents such as monoammonium phosphate or ammonium sulfate to smother fires and interrupt the chemical reaction.
- These extinguishers will be found in a variety of locations including: public hallways, laboratories, mechanical rooms, break rooms, chemical storage areas, offices, commercial vehicles, and other areas with flammable liquids.
- Available in different sizes and configurations, from small handheld units to larger wheeled models for industrial settings.
- Often identified by their distinctive red color and label specifying the types of fires they can extinguish. They range in size from five pounds to 20 pounds.
- Require regular inspection, maintenance, and periodic recharging to ensure proper functionality.
Knowledge Check Choose the best answer for the question.
1-5. Which class of fire extinguisher is used for fires that involve combustible metal powders, flakes, shavings?
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