Sources of Fire
- Fires are chemical reactions that occur when fuel, oxygen, and an ignition source combine.
- Fire extinguishers work by removing one or more of these sources, with different extinguishers working in different ways. For example, water extinguishers remove the heat and carbon dioxide (CO2) extinguishers remove the supply of oxygen. Five Classes of Fire
- Class A fires involve ordinary combustible materials, such as cloth, wood, paper, rubber, and many plastics.
- Class B fires involve flammable and combustible liquids, such as gasoline, alcohol, diesel oil, oil-based paints and lacquers, and flammable gases.
- Class C fires involve energized electrical equipment.
- Class D fires involve combustible metals, such as magnesium, titanium, and sodium.
- Class K fires involve vegetable oils, animal oils, or fats in cooking appliances.
Assessing a Fire Situation
- As portable fire extinguishers are designed for incipient-stage firefighting, employees should be familiar with how to properly asses a fire situation.
- Individuals should not use a portable fire extinguisher to combat fires larger than themselves.
- Individuals should also assess the fire’s location (is it fully visible or has it spread behind walls or equipment?), levels of heat (is the room too hot to remain in comfortably?), presence of thick smoke or fumes, and the availability of sufficient exit routes.
- Additionally, each organization should clearly instruct employees as to what alerting actions are required and when evacuation is required. Ideally, employees should never attempt to fight a fire without signaling that there is an emergency.
How to Use a Fire Extinguisher
It’s easy to remember how to use a fire extinguisher if you remember the