Required Training: Workplace Fire Extinguishers
OSHA requires that employees who have been designated to use fire extinguishers as part of your emergency action plan must be trained on how to use the fire extinguishers appropriately in the workplace, and on the hazards associated with fighting small or developing fires. The training is considered a specialized form of education that focuses on developing or improving skills, and it must be provided annually and when employees are first designated to use the extinguishers.
OSHA says that the following steps should be followed when responding to incipient-stage fires:
- Sound the fire alarm and call the fire department, if appropriate.
- Identify a safe evacuation path before approaching the fire. Do not allow the fire, heat, or smoke to come between you and your evacuation path.
- Select the appropriate type of fire extinguisher.
- Discharge the extinguisher within its effective range using the PASS technique (pull, aim, squeeze, sweep).
- Back away from an extinguished fire in case it flares up again.
- Evacuate immediately if the extinguisher is empty and the fire is not out.
- Evacuate immediately if the fire progresses beyond the incipient stage.
The different classes of fires-and their corresponding fire extinguishers-are designated as follows:
- Class A fires. These involve ordinary combustible materials such as:
- Wood, pallets, lumber
- Paper and cardboard
- Plastic and foam
- Class B fires. These involve flammable liquids such as:
- Grease that is often found in the kitchen
- Gasoline, kerosene, and other fuels
- Oil and other combustible liquids
- Common solvents such as paint thinners, mineral spirits, and common organic solvents found in a laboratory
- Class C fires. These involve energized electrical equipment such as:
- Appliances, including stoves, washing machines, dryers
- Switches, outlets, power cords, extension cords
- Panel boxes and circuit breakers
- Power tools, including drills, sanders, grinders, and saws
- Class D fires. These involve combustible metals such as:
- Magnesium metals, chips, or grinding dusts that can be found in some metal shops
- Titanium metals, chips, or grinding dusts that can be found in many aerospace sheet metal companies
- Potassium and sodium, which in their pure elemental forms are soft, ductile, malleable metals that can be easily cut with a knife or drawn into a wire
- Pyrophoric materials, which are highly reactive substances that are useful in the synthesis of organic chemicals
An additional designation, Class K (kitchen) fires, was added to the National Fire Protection Association (NFPA)
10 Standard for Portable Fire Extinguishers in 1998. Class K fires burn a specific type of fuel, namely cooking fat and oils, and can spread quickly, causing damage and potential injury. Class K flames are technically a subclass of class B flames, since it involves flammable liquid. However, because of some unique characteristics related to this type of fire, it was designated separately and requires a distinct battling method.
Fighting Class K Fires
Since this class of fire burns hotter than typical class B fires, the extinguishing methods used for B flames will not work on K flames. Some of the fire extinguishers rated for use with this type of cooking fire have a hood, which serves to cut off the oxygen and smother the flames.
Splashes of extremely hot cooking oil or fat can cause serious burns, even life-threatening injuries. Anyone attempting to put out the class K flames on their own should be well aware of the dangers. A firefighter must approach such a fire fully protected.
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