The fire triangle or combustion triangle is a simple model, from the science of firefighting, for understanding the ingredients necessary for most fires. Firefighters are rescuers extensively trained primarily to put out hazardous Fires that threaten civilian populations and property to rescue people from car accidents collapsed Fire is the heat and light energy released during a Chemical reaction, in particular a combustion reaction. It has largely been replaced in the industry by the fire tetrahedron, which provides a more complete understanding, also described below.
The triangle illustrates the rule that in order to ignite and burn, a fire requires three elements: heat, fuel, and an oxidizing agent, usually oxygen. In Physics, heat, symbolized by Q, is Energy transferred from one body or system to another due to a difference in Temperature Fuel is any material that is burned or altered in order to obtain energy An oxidizing agent or oxidising agent (also called an oxidant, oxidizer or oxidiser) can be defined as either a Chemical compound Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The fire is prevented or extinguished by removing any one of them. A fire naturally occurs when the elements are combined in the right mixture (e. g. , more heat is needed for igniting some fuels, unless there is concentrated oxygen).
- Without fuel, a fire will stop. Fuel can be removed naturally, as where the fire has consumed all the burnable fuel, or manually, by mechanically or chemically removing the fuel from the fire. Fuel separation is an important factor in wildland fire suppression, and is the basis for most major tactics, such as controlled burns. A wildfire, also known as a wildland fire, forest fire, brush fire, vegetation fire, grass fire, Peat fire, Other fuels may also be chemically altered to prevent them from burning at ordinary temperatures, perhaps as part of a fire-prevention measure.
- Without sufficient heat, a fire cannot begin, and it cannot continue. Heat can be removed by dousing some types of fire with water; the water turns to steam, taking the heat with it. Note that water will actually increase or spread some other types of fires (such as combustible metal fires, see comments below). Separating burning fuels from each other can also be an effective way to reduce the heat. In forest fires, burning logs are separated and placed into safe areas where there is no other fuel. Scraping embers from a burning structure also removes the heat source. Embers are the glowing hot coals made of greatly heated Wood, Coal or other carbon based material that remain after or sometimes precede a Fire. Turning off the electricity in an electrical fire removes the heat source, although other fuels may have caught fire and continue burning until the firefighter addresses them and their fire triangles too.
- Without sufficient Oxygen, a fire cannot begin, and it cannot continue. Oxygen may be removed from a fire by smothering it with an aqueous foam, or some inert gas (e. "Inert gases" is also used in a narrower sense for Noble gases An inert gas is any Gas that is not reactive with elements g. , carbon dioxide) or dry chemicals, or by enclosing it where the fire will quickly use up all of the available oxygen. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single A candle snuffer uses this principle. Oxygen for the fire may also be instantly consumed, if only for a moment, by more sophisticated means such as using explosives to 'snuff' an oil well gas fire. An explosive material is a material that either is chemically or otherwise Energetically unstable or produces a sudden expansion of the material usually accompanied West Texas PumpjackJPG|thumb|right|300px|This Pumpjack located south of Midland TX is a common sight in West Texas. Once the gas fire is out, it is not hot enough to start again, but workers must be extremely careful not to create sparks. See Red Adair. Paul Neal "Red" Adair ( June 18, 1915 &ndash August 7, 2004) was a renowned American oil field Firefighter
Fire tetrahedron
The fire triangle is a useful teaching tool, but fails to identify the fourth essential element of fire: the sustaining chemical reaction. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called This has led to development of the fire tetrahedron: a triangular pyramid having four sides (including the bottom). Some fire suppression agents do not remove or reduce any of the three necessary components, but rather interfere with their chemical combination, such as Halon. In most fires, it does not matter which element gets removed; the fire fails to ignite, or it goes out. However, there are certain chemical fires where knowing only the “fire triangle” is not good enough.
Combustion is the chemical reaction that feeds on a fire more heat and allows it to continue. Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of With most types of fires, the old fire triangle model works well enough, but when the fire involves burning metals (known as a class-D fire in the American system of fire classifications, involving metals like lithium, magnesium, etc. Ordinary combustibles "Ordinary combustible" fires are the most common type of fire and are designated "Class A" under both systems Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 ), it becomes useful to consider the chemistry of combustion. Putting water on such a fire could result in the fire getting hotter (or even exploding) because such metals can react with water in an exothermic reaction to produce flammable hydrogen gas. An explosion is a sudden increase in Volume and release of Energy in an extreme manner usually with the generation of high Temperatures and the release An exothermic reaction is a Chemical reaction that releases Heat. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Therefore, other specialized chemicals must typically be used to break the chain reaction of metallic combustion and stop the fire.
Fire square
The fire square is a model created by fire ecologist Richard W. Halsey. It shows how catastrophic wild fires, like the 2003 Cedar Fire, are formed. The Cedar Fire was a human-caused Wildfire which burned out of control through a large area of Southern California in October 2003 It includes the three original elements from the Fire Triangle, but adds an extra side, showing Extreme Weather as another important element. Some examples of extreme weather would be El Niño, hot Santa Ana Winds, or a long drought; excessive vegetation growth can be contributory too. El Niño-Southern Oscillation ( ENSO; commonly referred to as simply El Niño) is a global coupled ocean-atmosphere phenomenon The Santa Ana winds are strong extremely dry offshore Winds that characteristically sweep through in Southern California and northern Baja California in A drought is an extended period of months or years when a region notes a deficiency in its water supply A wildfire can only be caused if one of these are present at the time. During the Cedar Fire, Santa Ana winds were the cause of much of the fire's progress and re-kindling. The fire square was shown on an edition of 'The Weather Show'