Actually water IS used as a fire extinguisher - but not for all fires. Fire extinguishers are categorized by the "class" of fire they are intended to extinguish.
In the USA (other regions have different classification schemes):
Class A extinguishers are often (but not always) just water under pressure and are intended to extinguish fires where solid organic materials such as wood or paper are burning.
Class B extinguishers are designed to put out burning liquid fires like oil, grease, gasoline, industrial solvents, etc. CO2 and foam are often used in these extinguishers. Water is not suitable because it would tend to just spread the liquid around and the burning liquid would float on top of the water and continue to burn. Even so, firefighters will often spray water over huge burning liquid fires (as a spray or mist) to cool things down and inhibit the spread of the fire to nearby flammable structures.
Class C extinguishers are designed to fight electrical fires. The problem with using water in these extinguishers should be apparent - the water would conduct the electricity and increase the hazard not to mention causing additional shorting which can destroy other electrical equipment not involved in the fire.
Class D extinguishers are designed to fight burning metal fires. Since many metals react with water to give off other flammable gases, pouring water on them is hardly a good solution. As an example - when pure sodium is placed into water it bursts into flames and give off Hydrogen gas.
There is also a Class K extinguisher that is intended for grease and oil fires such as might flare up in a pan in a kitchen. they overlap the Class B extinguishers somewhat.
Water removes the heat from the fire and disrupts the chemical reaction (oxidization).
Any fire that is not electrical, nor fuelled by flammable liquids.
For flammable liquids, foam extinguishers are the trick, and for electrical, foam or powder.
There are many types of fires that water would actually make worse, such as electrical fires and certain chemical fires.
it removes heat from the fire
Fire extinguishers are best used on incipient (at the beginning) fires.
FIRE extinguishers are used to put out fire.
Nitrogen can be used in fire extinguishers as gas propellant.
Carbon dioxide fire extinguishers are generally used because they absorb the oxygen content present in the air and thus help in extinguishing fire.
Yes, Halon fire extinguishers can be used on electrical equipment- and in fact are often recommended.
The carbon dioxide fire extinguisher can be used on electrical fires, where there is a danger of an electrical shock if a soda water extinguisher was used.
There are two main types of fire extinguishers: stored pressure and cartridge-operated. In stored pressure units, the expellant is stored in the same chamber as the firefighting agent itself. Depending on the agent used, different propellants are used. With dry chemical extinguishers, nitrogen is typically used; water and foam extinguishers typically use air. Stored pressure fire extinguishers are the most common type
Class C fire Extinguishers
A fire extinguisher cools down or extinguishes a fire. There are five types of fire extinguishers used in the US.
Extinguishers with a Class C rating (C can be used on Currents)
No, not really. Fire extinguishers and fire blankets are used to stop fires. The "accident" would have already occurred, starting the fire.
water, helium and water vapor.