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The fire triangle is a simple model, from the science of firefighting, for understanding the ingredients necessary for most fires. It has largely been replaced in the industry by the fire tetrahedron, which provides a more complete model, also described below. Image File history File links Fire_triangle. ...
Image File history File links Fire_triangle. ...
Firefighter in full turn out gear with a pickhead axe. ...
It has been suggested that flame be merged into this article or section. ...
The “triangle” illustrates the rule that in order to ignite and burn, a fire requires three elements — heat, fuel, and oxygen. 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 needed for igniting some fuels, unless there is concentrated oxygen).
- When a fire runs out of fuel it 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. 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. 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. 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.
- Oxygen may be removed from a fire by smothering it with an aqueous foam, or some inert gas (e.g., carbon dioxide, Halon), dry chemicals, or enclosing it where the fire will quickly use up all of the available oxygen. A candle snuffer uses this principle. Oxygen for the fire may also be instantaneously consumed, if only for a moment, by more ‘sophisticated’ means such as using explosives to ‘snuff’ an oil well gas fire. 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 .
The Old Fire burning in the San Bernardino Mountains (image taken from the International Space Station) A wildfire, also known as a forest fire, vegetation fire, grass fire, brush fire, or bushfire (in Australasia), is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or...
An inert gas is any gas that is not reactive under normal circumstances. ...
Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ...
Halon 1211 and Halon 1301 are special-purpose fire extiguishing agents that were banned by the Montreal Protocol. ...
This article is concerned solely with chemical explosives. ...
An oil well is a term for any perforation through the Earths surface designed to find and release both petroleum oil and gas hydrocarbons. ...
Paul Neal Red Adair (June 18, 1915 – 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. This has led to development of the fire tetrahedron: a triangular pyramid having four sides (including the bottom). 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. Image File history File links Fire_tetrahedron. ...
Image File history File links Fire_tetrahedron. ...
A chemical reaction is a process that results in the interconversion of chemical substances [1]. The substance or substances initially involved in a chemical reaction are called reactants. ...
Combustion is the chemical reaction that feeds a fire more heat and allows it to continue. With most types of fires, the old fire triangle model works well enough, but when the fire involves burning metals (lithium, magnesium, etc.), 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. Therefore, other specialized chemicals must typically be used to break the chain reaction of metallic combustion and stop the fire. Combustion or burning is a chemical process, an exothermic reaction between a substance (the fuel) and a gas (the oxidizer), usually O2, to release heat. ...
General Name, Symbol, Number lithium, Li, 3 Chemical series alkali metals Group, Period, Block 1, 2, s Appearance silvery white/gray Atomic mass 6. ...
General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ...
Gasoline explosions, simulating bomb drops at an airshow. ...
In chemistry, an exothermic reaction is one that releases heat. ...
General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...
Fire Square The Fire Square is model created by fire ecologist Richard W. Halsey. It shows how catastrophic wild fires, like the 2003 Cedar Fire, are formed. 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, a long drought, or excessive vegetation growth. A wild fire can only be caused if one of these are present at the time. During the Cedar fire, Santa Ana winds were the cause for much of the fire's progress and re-kindling. The Fire Square was shown on an edition of The Weather Show. Richard West Halsey (1955- ), is one of the leading fire ecologists in California, considered by some to be second only to John E. Keeley. ...
Southern California ablaze on October 26, 2003. ...
Chart of ocean surface temperature anomaly [°C] during the last strong El Niño in December 1997 El Niño and La Niña (also written in English as El Nino and La Nina) are major temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. ...
Santa Ana winds are warm, dry winds that characteristically appear in Southern California weather during autumn and early winter. ...
A drought or an extreme dry periodic climate is an extended period where water availability falls below the statistical requirements for a region. ...
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