It is a great tact to fight the fire.

Such as fire is a combination of three elements, if we want to fight the fire we will have to cut off any one element then fire automatically turn off.

There are three way to follow above mentioned Fire Fighting process

1.    COOLING

2.  SMOTHERING

3.   STARVING

 

 

 

1.    COOLING

 

 From three elements of fire Oxygen, Heat and Fuel.  Now we remove one element HEAT from that three elements.  what is the way to cut off HEAT from FIRE?

 To cut off the HEAT from fire we can use Water.  It is mostly available source for fire fighting and it is also not expensive method to control the fire and cut off the HEAT.  This procedure is called COOLING.

 

2.  SMOTHERING

 

2nd procedure of Fire Fighting is Smothering. It's mean to cut off OXYGEN from air and remove the OXYGEN from three elements of fire.  For this method we use a fire extinguisher which called  Aqueous Film Forming Foam (AFFF).  AFFF provide a cover on a fire surface and cut off OXYGEN and remove the fire.  It's called Smothering procedure.

 

 

3.   STARVING

 

 

 

 

 

Comparison of fire classes

American	European	Australasian	Fuel/Heat source
Class A	Class A	Class A	Ordinary combustibles
Class B	Class B	Class B	Flammable liquids
	Class C	Class C	Flammable gases
Class C	-	Class E	Electrical equipment
Class D	Class D	Class D	Combustible metals
Class K	Class F	Class F	Cooking oil or fat

Ordinary combustibles

"Ordinary combustible" fires are the most common type of fire, and are designated Class A under both systems. These occur when a solid, organic material such as wood, cloth, rubber, or some plastics^[1] become heated to their ignition point. At this point the material undergoes combustion and will continue burning as long as the four components of the fire tetrahedron (heat, fuel, oxygen, and the sustaining chemical reaction) are available.

This class of fire is commonly used in controlled circumstances, such as a campfire, match or wood-burning stove. To use the campfire as an example, it has a fire tetrahedron—the heat is provided by another fire (such as a match or lighter), the fuel is the wood, the oxygen is naturally available in the open-air environment of a forest, and the chemical reaction links the three other facets. This fire is not dangerous, because the fire is contained to the wood alone and is usually isolated from other flammable materials, for example by bare ground and rocks. However, when a class-A fire burns in a less-restricted environment the fire can quickly grow out of control and become a wildfire. This is the case when firefighting and fire control techniques are required.

This class of fire is fairly simple to fight and contain—by simply removing the heat, oxygen, or fuel, or by suppressing the underlying chemical reaction, the fire tetrahedron collapses and the fire dies out. The most common way to do this is by removing heat by spraying the burning material with water; oxygen can be removed by smothering the fire with foam from a fire extinguisher; forest fires are often fought by removing fuel by backburning; and an ammonium phosphate dry chemical powder fire extinguisher (but not sodium bicarbonate or potassium bicarbonate both of which are rated for B-class^[2] fires) breaks the fire's underlying chemical reaction.

As these fires are the most commonly encountered, most fire departments have equipment to handle them specifically. While this is acceptable for most ordinary conditions, most firefighters find themselves having to call for special equipment such as foam in the case of other fire.

Flammable liquid and gas

A CO₂ fire extinguisher rated for flammable liquids and gasses

These are fires whose fuel is flammable or combustible liquid or gas. The US system designates all such fires "Class B". In the European/Australian system, flammable liquids are designated "Class B", while burning gases are separately designated "Class C". These fires follow the same basic fire tetrahedron (heat, fuel, oxygen, chemical reaction) as ordinary combustible fires, except that the fuel in question is a flammable liquid such as gasoline, or gas such as natural gas. A solid stream of water should never be used to extinguish this type because it can cause the fuel to scatter, spreading the flames. The most effective way to extinguish a liquid or gas fueled fire is by inhibiting the chemical chain reaction of the fire, which is done by dry chemical and Halon extinguishing agents, although smothering with CO₂ or, for liquids, foam is also effective. Halon has fallen out of favor in recent times because it is an ozone-depleting material; the Montreal Protocol declares that Halon should no longer be used. Chemicals such as FM-200 are now the recommended halogenated suppressant.

Electrical

Electrical fires are fires involving potentially energized electrical equipment. The US system designates these "Class C"; the Australian system designates them "Class E". This sort of fire may be caused by short-circuiting machinery or overloaded electrical cables. These fires can be a severe hazard to firefighters using water or other conductive agents: Electricity may be conducted from the fire, through water, the firefighter's body, and then earth. Electrical shocks have caused many firefighter deaths.

Electrical fire may be fought in the same way as an ordinary combustible fire, but water, foam, and other conductive agents are not to be used. While the fire is or possibly could be electrically energized, it can be fought with any extinguishing agent rated for electrical fire. Carbon dioxide CO₂, FM-200 and dry chemical powder extinguishers such as PKP and even baking soda are especially suited to extinguishing this sort of fire. PKP should be a last resort solution to extinguishing the fire due to its corrosive tendencies. Once electricity is shut off to the equipment involved, it will generally become an ordinary combustible fire.

In Europe "Electrical Fires" are no longer a class of fire as electricity can not burn. The items around the electrical sources may burn. By turning the electrical source off, the fire can be fought by one of the other class of fire extinguishers.

Metal

Certain metals are flammable or combustible. Fires involving such are designated "Class D" in both systems. Examples of such metals include sodium, titanium, magnesium, potassium, uranium, lithium, plutonium, and calcium. Magnesium and titanium fires are common. When one of these combustible metals ignites, it can easily and rapidly spread to surrounding ordinary combustible materials.

With the exception of the metals that burn in contact with air or water (for example, sodium), masses of combustible metals do not represent unusual fire risks because they have the ability to conduct heat away from hot spots so efficiently that the heat of combustion cannot be maintained—this means that it will require a lot of heat to ignite a mass of combustible metal. Generally, metal fire risks exist when sawdust, machine shavings and other metal 'fines' are present. Generally, these fires can be ignited by the same types of ignition sources that would start other common fires.

Water and other common firefighting materials can excite metal fires and make them worse. The NFPA recommends that metal fires be fought with "dry powder" extinguishing agents. Dry powder agents work by smothering and heat absorption. The most common of these agents are sodium chloride granules and graphite powder. In recent years powdered copper has also come into use.

Some extinguishers are labeled as containing dry chemical extinguishing agents. This may be confused with dry powder. The two are not the same. Using one of these extinguishers in error, in place of dry powder, can be ineffective or actually increase the intensity of a metal fire.

Metal fires represent a unique hazard because people are often not aware of the characteristics of these fires and are not properly prepared to fight them. Therefore, even a small metal fire can spread and become a larger fire in the surrounding ordinary combustible materials.

Cooking oils and fats (kitchen fires)

Fires that involve cooking oils or fats are designated "Class K" under the American system, and "Class F" under the European/Australasian systems. Though such fires are technically a subclass of the flammable liquid/gas class, the special characteristics of these types of fires, namely the higher flash point, are considered important enough to recognize separately. Saponification can be used to extinguish such fires, as can dry-powder, CO2 or, for small fires, mechanical smothering. Appropriate fire extinguishers may also have hoods over them that help extinguish the fire.

The 4 most common types of fire

Kitchen, electrical, heater and smoking-related fires are the four most common types of fires

 

While fires can start at anytime and anywhere, below are descriptions of the four most common types of fires. Acknowledging these types of fires may help you to reduce or even eliminate the risk of starting a fire.

1. The most common type of fire in the U.S. is the kitchen fire. The reason that the kitchen is the source of many fire hazards is because the kitchen is where heat, electricity, water, and grease come together.

The most common type of kitchen fire is the grease fire. A grease fire is extremely dangerous as it can get out of control quickly and spread from the stove throughout the kitchen and into other rooms of the house.

Many grease fires occur because someone leaves a frying pan on the stove unattended. They also occur when someone overheats a pan during attended cooking if the grease catches fire. Grease fires can cause serious injury and extensive property damage.

Other types of kitchen fires include oven fires and appliance fires. Fires can also get started in the kitchen when electricity comes in contact with water.

2. Electrical fires are another common type of fire. Electrical fires are caused by a number of different factors, including faulty appliances, worn or faulty electrical wiring, improper use of electrical outlets and worn out breaker boxes.

Older homes often do not have the proper wiring to handle the amount of electrical appliances in use today. Often old wiring inside walls becomes frayed or worn, causing shorts and sparks that can ignite.

Old breaker boxes are made to shut off electrical current when the circuit becomes overloaded as a fire prevention measure, but often the connections are worn or broken and do not activate the breaker switch.

Lighting is another cause of electrical fires, which can be triggered by improper wiring or the use of bulbs that are higher in wattage than the amount recommended for the lighting appliance.

3. Heater fires are among the most common types of fires in the months of December, January and February. Portable heaters should always have automatic shutoffs that activate when they overheat as a fire precaution.

Coil space heaters are especially hazardous because the coils will ignite anything combustible nearby. Always keep any type of space heater a minimum of three feet from anything combustible. That includes curtains, bedding, clothing and furniture. Always shut space heaters off when you’re not in the room.

Extension cords should not be used with space heaters as they generate too much electricity and can start a fire.

4. Another major type of fire is smoking-related. Fires caused by cigarettes account for 1,000 deaths in the U.S. every year. Many times the smoker is not the person who dies.

Most smoking fires are started by embers igniting on furniture, bedding and trash cans. Smokers should always be sure cigarettes are completely extinguished before emptying ashtrays into the trash.

Never smoke in bed and never smoke when you are tired, inebriated, or drowsy from medication. Do not place ashtrays on flammable surfaces like couches, chairs, or beds where they can tip over and start a fire.

The best way to prevent smoking-related fires is to smoke outside the house and have a can filled with sand to extinguish cigarette butts.

 

Triangle of Fire

Fire is the combination of the three elements which consists of Oxygen, Fuel and Heat.  If some elements of fuel, oxygen and heat are available in any condition they can not produce Fire, Fire can be produced in only that condition when these three elements will be combined in a specific conditions.

Chemistry

Fires start when a flammable and/or a combustible material, in combination with a sufficient quantity of an oxidizer such as oxygen gas or another oxygen-rich compound (though non-oxygen oxidizers exist that can replace oxygen), is exposed to a source of heat or ambient temperature above the flash point for the fuel/oxidizer mix, and is able to sustain a rate of rapid oxidation that produces a chain reaction. This is commonly called the fire tetrahedron. Fire cannot exist without all of these elements in place and in the right proportions. For example, a flammable liquid will start burning only if the fuel and oxygen are in the right proportions. Some fuel-oxygen mixes may require a catalyst, a substance that is not directly involved in any chemical reaction during combustion, but which enables the reactants to combust more readily.

Once ignited, a chain reaction must take place whereby fires can sustain their own heat by the further release of heat energy in the process of combustion and may propagate, provided there is a continuous supply of an oxidizer and fuel.

If the oxidizer is oxygen from the surrounding air, the presence of a force of gravity, or of some similar force caused by acceleration, is necessary to produce convection, which removes combustion products and brings a supply of oxygen to the fire. Without gravity, a fire rapidly surrounds itself with its own combustion products and non-oxidizing gases from the air, which exclude oxygen and extinguish it. Because of this, the risk of fire in a spacecraft is small when it is coasting in inertial flight. Of course, this does not apply if oxygen is supplied to the fire by some process other than thermal convection.

Fire can be extinguished by removing any one of the elements of the fire tetrahedron. Consider a natural gas flame, such as from a stovetop burner. 


Let's explain what fire is... 

Fire is a chemical process. Three things are needed for this process: oxygen, heat and fuel. Without one of these elements a fire cannot start or continue.  In a chemical process, the molecules rearrange themselves. Energy is either released or absorbed. The process in a fire is called oxidation, where oxygen atoms combine with hydrogen and carbon to form water and carbon dioxide. Oxidation is the same chemical process that turns iron into rust. But with iron, the reaction is VERY slow. So, the heat energy that is released is VERY low. With certain things, like paper or wood, the oxidation rate of the molecules can be very fast. If the heat cannot be released faster than it is created, then combustion happens.Besides heat, there must also be flames or smoldering present during the chemical process for it to be called fire. Exhaust gases also are produced. If the burning process is very clean, you don't see the exhaust gases. If some of the particles of the fuel are not completely burned, you see smoke. Smoke is made up of evaporated water, carbon dioxide and unburnt particles of the fuel.  

DEFINITION OF FIRE

• a process in which substances combine chemically with oxygen from the air and typically give out bright light, heat, and smoke; combustion or burning:his house was destroyed by fire
• [count noun] a destructive burning of something:a fire at a hotel
• [count noun] a collection of fuel, especially coal or wood, burnt in a controlled way to provide heat or a means for cooking:we had a bath in a tin tub by the fire
• [count noun] (also electric fire or gas fire) chiefly British a domestic heating appliance that uses electricity or gas as fuel: she was freezing and keeping the fire low to save money
• one of the four elements in ancient and medieval philosophy and in astrology (considered essential to the nature of the signs Aries, Leo, and Sagittarius): [as modifier]:a fire sign

• 2a burning sensation: [count noun]:the whisky lit a fire in the back of his throat
• fervent or passionate emotion or enthusiasm:the fire of their religious conviction
• literary a glowing or luminous quality:their soft smiles light the air like a star’s fire

• 3the shooting of projectiles from weapons, especially bullets from guns:a burst of machine-gun fire
• strong criticism or antagonism:he directed his fire against policies promoting American capital flight

verb

[with object]

• 1discharge a gun or other weapon in order to propel (a bullet or projectile):he fired a shot at the retreating prisoners they fired off a few rounds
• discharge (a gun or other weapon):another gang fired a pistol through the window of a hostel [no object]:troops fired on crowds
• [no object] (of a gun) be discharged: the first gun fired
• direct (questions or statements, especially unwelcome ones) towards someone in rapid succession:they fired questions at me for what seemed like ages
• (fire something off) send a message aggressively:he fired off a letter informing her that he regarded the matter with the utmost seriousness