Fire is a form of heat energy generated by chemical reactions. It sustains itself by generating new heat. Gasoline burns in one step. The heat it generates vaporizes the fuel, leaving no char behind. It is this chemistry that has allowed humans to develop the ability to meter fuel. Similarly, candles slowly vaporize wax, and emit visible, infrared, and sometimes ultraviolet light. And they are self-perpetuating.
Flames emit visible, infrared, and sometimes ultraviolet light
The flame detection technology available today is capable of detecting fires in the visible, infrared, and sometimes even ultraviolet bands. These detectors comprise multiple channel arrays of sensors that monitor light from fires. These devices have improved response time and false alarm immunity. UV sensors detect flames emitting UV radiation while IR sensors monitor fires emitting light in the infrared band.
They expand outward like other gases
Flames are the result of a rapid reorganization of molecules in fire. They don’t form a circle, but rather spread outward like all other gases in fire. The flames appear to expand outward because the hot gases are less dense than the air surrounding them. Luckily, the astronauts on the space station Mir were able to survive the fire. This fire science fact can help you understand the flames around you.
They produce a lot of heat energy
The type of fuel that causes a fire will determine how much heat is generated. Different fuels burn at varying temperatures, and this energy is converted into a gas when they react with oxygen. There are many factors that contribute to the amount of heat generated, including fuel composition and moisture content. In addition to fuel composition, moisture content will affect the amount of heat produced by a fire. If the fuel contains water, for example, it will burn much more slowly.
They are self-perpetuating
Why do fires continue to burn? This answer may surprise you, but fires are self-perpetuating by nature. Fires burn because the chemical reactions between fuel and oxygen continuously generate heat energy. Moreover, the flame will never die unless fuel and oxygen are continually replenished. This process means that fires can grow in both size and spread to other areas, destroying buildings, trees, and human life.
They can spread quickly
The speed at which fires spread is terrifying. In less than two minutes, a small fire can become a major fire, engulfing a house in black smoke and flames. Within five minutes, a house can be fully consumed. Depending on the size and construction, commercial buildings can take much longer. In addition to speed, fires spread quickly because of the presence of elevators and other large structures.