A fire extinguisher is a portable device that is used to put out a fire. These devices come in many different forms and types, depending on the type of fuel they can deal with.
The most common type of fire extinguisher is the water-based extinguisher. This can be a handheld or cart-mounted unit, depending on its size and weight.
They are generally placed near entrances and exits to prevent the onset of fires in these areas. They are also kept on hand in rooms and buildings where fires are most likely to start, such as the kitchen or garage.
In general, the most important thing to remember when using a fire extinguisher is to make sure it is aimed at the base of the fire and not at its edges or top. Once the fire is under control, you can then move away from it, or evacuate the building.
There are six main types of fire extinguishers: water mist, dry powder, liquid chemical, vapor, CO2, and gas-extinguishing. There are even special purpose extinguishers, such as chemical foams, compressed air foam systems and hydrant water sprays, that can be used to deal with specific types of fires.
The water-based extinguisher is the most common of the six, and it works on a variety of classes of fires. It has a nozzle or horn that discharges microscopic water molecules into the area of the fire. This causes the water to evaporate, creating a fog that suffocates the fire and prevents oxygen from getting into the flames.
It can also reduce the temperature of the fire, helping to extinguish it. It can also be used on electrical fires, although this requires special testing to ensure it is safe.
Another type of extinguisher is the liquid chemical, which uses a mixture of water, a solvent, and an acid to smother a fire. These are used for Class B fires that involve flammable liquids, greases and oils.
These extinguishers are generally more expensive than the water-based type and are often used by professionals in their field, such as firefighters or safety technicians. They are designed to handle a wide range of fires and are usually rated for use on both Class A and B fires.
The liquid chemical extinguishers are divided into two groups: those containing carbon dioxide and those that contain a dry chemical agent (such as monoammonium phosphate). Carbon dioxide is a compressed gas that displaces oxygen, preventing combustion.
There are a few other dry chemical extinguishers, including those that contain ordinary sodium potassium bicarbonate, urea potassium bicarbonate or potassium chloride base agents. These extinguishers are used on Class A, B and C fires.
Graphite-based (G-Plus, G-1, Lith-X, Chubb Pyromet) are dry graphite extinguishers that smother the burning of metals such as magnesium. These extinguishers are more effective than the sodium chloride extinguishers on Class A and B fires, but not as good on Class C fires.
Foam extinguishers are water-based foams that create a thick layer of frothy foam that smothers the fire and excludes oxygen. They are used on Class A, B, and C fires and for vapor suppression.