not how you use them, but phisycally and chemicaly
Fire extinguisher work by removing one part of a four part list of requirements to make fire. Professionals call this the Fire Tetrahedron. The four items are, heat, fuel oxygen and the chemical reaction. The most common fire extinguisher is a pressurized water extinguisher. It uses compressed air to force a stream of water out a nozzle on to a fire. The water cools the burning material taking away one leg of the fire tetrahedron (heat). The next most common fire extinguisher is the Dry Chemical extinguisher, it is a dry powder that interferes with chemical reaction and removes it from the tetrahedron. The next is the Carbon Dioxide extinguisher. It isolates the fuel from the oxygen by surrounding the fuel with an atmosphere of CO2. Therefore oxygen is removed from the tetrahedron. There are other extinguishers meant for specialty situations or specific fuels.
They all typically work the same way: A fire needs three things to keep burning: fuel, heat, and oxygen If you remove any one of these things, the fire can't maintain itself and will go out. A water extinguisher works by reducing heat and removing oxygen by smothering the flame A chemical extinguisher works by removing the oxygen by smothering A carbon dioxide extinguisher also works by smothering the fire and removing the oxygen. It also reduces heat. Also, any of these extinguishers may remove the fuel by knocking it out of the way or getting between the fire and the fuel.
There are many types of fire extinguishers to start with. The most common is CO2 fire extinguishers. Carbon Dioxide (CO2) is packed in a tank (the fire extinguisher container) under pressure. Gases with the application of pressure usually liquify. With the proper manipulation of the releasing mechanism of the fire extinguisher nozzle, the CO2 is then spayed into the fire. Once out, pressure is relieved, so much heat is given off that it condenses into a snowy form while still in the air. When it strikes the embers, it turns again to gaseous form and envelops the fire source so that Oxygen is cut off. Since CO2 itself is nonflamable, the fire is put out, not being able to get its supply of Oxygen from the air anymore. But on windy days, the CO2 blanket may be blown away after sometime, and fire may rekindle again if the burning materials are not removed effectively.
