There is a lot to fire extinguisher's, here's a description of the basics of the ratings, can you name the 5 ratings?

    Fire Extinguisher's, I have several around the house, in the boat and on the patio by the BBQ. United Laboratory classifies them in two ways, the first method describes the contents. The second is a quick reference symbol and letter designation. ( The US Fire Administration Talks about choosing fire extinguishers, click here.)
    4A:20B:C, is an example of the numerical rating of the extinguishers as follows: The "A" tells us it's filled with water, 1 1/2 gallons, when a "4" is placed before the "A" the volume is then 4 gallons + (A) 1 1/2 gallons = 5 gallons. The B:C rate is equivalent to the coverage in square feet, so 20 B:C = 20 square foot coverage (as applied by a professional). This rating system enables us to add logic to choosing the type we need. This is designated on a tag or label on the extinguisher.
    The rating's most of us are familiar with and the way we identify fire extinguisher's is by their contents, which contents extinguish which fires.

There are many shapes and sizes available, look at the rating
and the class designation.

    "A" class rating is filled with water, the numeric rating tells us how much. The designation tells us we can use this for extinguishing combustibles, paper, wood, clothe and solids that are not metal. An "A" extinguisher should never be used on electrical fires, grease fires or flammable metals. The letter symbol "A" is in the center of a triangle with a green background, the words "ordinary combustibles" is printed below it.
     "B" class rating is meant to be used on fires fueled with liquid, oil, gasoline, diesel and grease to name some. The "B" extinguisher is filled with one of two types of solid flame extinguisher agents. The first is Mono-ammonium phosphate meant to smother the fire. The second is sodium bicarbonate (baking soda) which begins a chemical reaction successfully putting the fire out. Do not use a water filled unit on this type of fire, it will spread the flames, oil floats.
     "C" class ratings are meant to be used on "live" electrical fires, they must be smothered. Mono-ammonium phosphate and sodium bicarbonate (baking soda) are two agents commonly charging class "C" extinguishers. Do not use water (class "A") on a live electrical fire, you could be electrocuted. If possible electrical power should be disconnected from the charged electrical system prior to extinguishing it.

A typical type of class "A" fire, don't hesitate to run if the
situation becomes too intense, it takes courage to perform
as this lady is. 

    "D" class rating are used to extinguish fires involving magnesium, sodium, potassium and sodium potassium alloys. Metals that form an oxygen bubble over them (magnesium) and create their own atmosphere which must be "pierced" to access the fire. A common point of this type of fire would be an airplane tire/wheel fire, they are typically magnesium.
    "K" class rating is used to extinguish kitchen fires with the various combustible materials used to cook. Made to put out cooking oils and deep fryers. The numeric rating might read 2A:K would contain 2 1/2 gallons water and with this designation is approved to be used on a class K (cooking oil) fire.
    Purchase fire extinguisher's and place them in the room or area they are made for.
    There is four types of contents for fire extinguisher's, also describing the "Types" of extinguisher's, they are:
    Dry chemical normally rated for multiple uses, generally propelled by an inert gas.
    Halon is a gas that removes the oxygen from a fire, common uses include use in computer rooms , machinery rooms and electrical control panels.
    Water is also commonly propelled by an inert gas, some older styles are "pump" style. The more you pump the more air that is pushed in the vessel to build up propulsion pressure.
    Carbon Dioxide is many times used in class B and C rated extinguisher's. It is a liquid inside the vessel, when released it expands and cools the ambient air, causing ice to form around the nozzle. CO2 takes the place of oxygen thus putting it out due to lack of air.
    Thanks for reading, this is a very basic description of fire extinguisher's with the intent of explaining the A-B-C-D-K rating system of United Labs. Go to this link for more information on the contents of extinguisher's.

Training includes this method, it works. 

jimandkate  emergencykitsplus.com  Emergency Preparedness Supplies