different types of extinguisher and what are they used for?

Answer 1

Fire Extinguisher Ratings

Class A Extinguishers will put out fires in ordinary combustibles, such as wood and paper. The numerical rating for this class of fire extinguisher refers to the amount of water the fire extinguisher holds and the amount of fire it will extinguish.

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Class B Extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc. The numerical rating for this class of fire extinguisher states the approximate number of square feet of a flammable liquid fire that a non-expert person can expect to extinguish.

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Class C Extinguishers are suitable for use on electrically energized fires. This class of fire extinguishers does not have a numerical rating. The presence of the letter “C” indicates that the extinguishing agent is non-conductive.

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Class D Extinguishers are designed for use on flammable metals and are often specific for the type of metal in question. There is no picture designator for Class D extinguishers. These extinguishers generally have no rating nor are they given a multi-purpose rating for use on other types of fires.

Answer 2

Class A extinguishers will put out fires in ordinary combustibles, such as wood and paper.

Class B extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc.

Class C extinguishers are suitable for use on electrically energized fires. The presence of the letter “C” indicates that the extinguishing agent is non-conductive.

Class D Extinguishers are designed for use on flammable metals and are often specific for the type of metal in question.

Dry Chemical extinguishers are usually rated for multiple purpose use. They contain an extinguishing agent and use a compressed, non-flammable gas as a propellant.

Halon extinguishers contain a gas that interrupts the chemical reaction that takes place when fuels burn. These types of extinguishers are often used to protect valuable electrical equipment since them leave no residue to clean up. Halon extinguishers have a limited range, usually 4 to 6 feet.

Carbon Dioxide (CO2) extinguishers are most effective on Class B and C (liquids and electrical) fires. Since the gas disperses quickly, these extinguishers are only effective from 3 to 8 feet.

Many extinguishers available today can be used on different types of fires and will be labeled with more than one designator, e.g. A-B, B-C, or A-B-C.

Answer 3

Water is the most familiar extinguishing material, and it is one of the most effective. But it can be dangerous in the wrong situation. A water extinguisher can put out things like burning wood, paper or cardboard, but it does not work well on electrical fires or fires involving inflammable liquids. In an electrical fire, the water may conduct the current, which can electrocute you. Water will only spread out an inflammable liquid, which will most likely make the fire worse.
One popular extinguisher material is pure carbon dioxide. In a carbon dioxide extinguisher, the carbon dioxide is kept in pressurized liquid form in the cylinder. When the container is opened, the carbon dioxide expands to form a gas in the atmosphere. Carbon dioxide gas is heavier than oxygen, so it displaces the oxygen surrounding the burning fuel. This sort of fire extinguisher is common in restaurants because it won't contaminate the cooking equipment or food.

The most popular extinguisher material is dry chemical foam or powder, typically made of sodium bicarbonate (normal baking soda), potassium bicarbonate (nearly identical to baking soda), or monoammonium phosphate. Baking soda starts to decompose at only 158 degrees Fahrenheit (70 degrees Celsius), and when it decomposes, it releases carbon dioxide. The carbon dioxide, along with the insulation of the foam, works to smother the fire.

Most fire extinguishers contain a fairly small amount of fire-suppressant material -- you can use it all up in a matter of seconds. For this reason, extinguishers are only effective on relatively small, contained fires. To put out a larger fire, you need much bigger equipment -- a fire engine, for example -- and the professionals who know how to use it. But for the dangerous flames that can pop up in your house, a fire extinguisher is an invaluable lifesaver.



Extinguisher Ratings
Fire extinguishers are rated by the type of fire they can put out.

Class A extinguishers can put out fires from "ordinary combustibles" such as wood, plastic or paper. Class B can put out burning liquids such as gasoline or grease. Class C can put out electrical fires. Extinguishers marked A, B and C can put out all types. Class D extinguishers, designed to put out burning metal, are rare. Check the letters and pictures on your extinguisher to find out what it can handle.

Water is the most familiar extinguishing



For more detailed info please visit the link given below

http://home.howstuffworks.com/fire-extinguisher.htm

Answer 4

(Red) - Water, used for paper, wood etc...

(Yellow) - Foam, used on oils, fats, petroleum etc....

(Black) - CO2, Can be used on anything, especially useful for electrical fires.

(Blue) - Powder, Can also be used on pretty much anything.