About This Quiz
Having a fire extinguisher handy when you need it may save your life. Find out how fire extinguishers work and how to use them correctly. Our fact-filled quiz will get you started.For a fire to occur, there needs to be oxygen; the absence of oxygen will cause a fire to extinguish. The reaction between oxygen and a fuel such as gasoline or wood is known as a chemical combustion reaction.
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Fuels need more than just the presence of oxygen to ignite. For a combustion reaction to occur, the fuel has to be heated to its ignition temperature.
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Focused light, when a mirror reflects the sun onto an object, or friction, when two sticks of wood are rubbed together, can both cause enough heat to ignite a fire.
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Fire extinguishers work by neutralizing at least one of the three elements -- heat, oxygen or fuel -- needed to sustain a fire.
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When you put water on a fire, it acts to cool the fuel to below the ignition point, interrupting the combustion cycle.
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The best way to remove oxygen from a fire is to cut it off from its oxygen supply. To smother a small fire, cover it with a heavy blanket or dump a nonflammable material such as sand or baking soda on top of it.
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Fire extinguishers are metal cylinders filled with water or a chemical smothering material. When you activate the extinguisher, the material is expelled under high pressure.
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As per the recommendation of the National Fire Protection Association, you should have dry extinguishers inspected every six years even if the gauge indicates adequate pressure.
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Most dry-chemical fire extinguishers have a built-in pressure gauge. Check the gauge often to be sure that the pressure is not too low to expel the contents properly.
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At the top of the main cylinder, there is a small cylinder filled with compressed gas. A release valve keeps the compressed gas from escaping.
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To use your fire extinguisher, pull out the safety pin and press down on the lever. This sets in motion the release of the fire-suppressant material.
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The function of the metal safety pin on your fire extinguisher is to prevent the operating lever from closing accidentally.
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A fire extinguisher that uses pure carbon dioxide is popular in restaurants because it won't contaminate the cooking equipment or food. Carbon dioxide gas, which is heavier than oxygen, displaces the oxygen surrounding the burning fuel.
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The fire extinguisher in your home is probably the kind that uses a dry chemical foam or powder made of sodium bicarbonate (baking soda), potassium bicarbonate (very similar to baking soda) or monoammonium phosphate. The carbon dioxide released when the baking soda decomposes, along with the insulation of the foam, smothers the fire.
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Fire extinguishers are rated by the type of fire they can put out: Class A extinguishers can put out fires involving "ordinary combustibles," Class B extinguishers can put out fires involving burning liquids and Class C can put out electrical fires. Some extinguishers can put out all three, but all fire extinguishers are meant for small, contained fires; for a fire that's spread, call the fire department.
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