The elements of fire are Fuel, Oxygen, Heat, and Convection. Each of these elements plays a role in the growth of fire. We will discuss each one individually to better understand how these elements cause a fire. For example, cellulose is made up of water and will be driven out of plant cells when the temperature rises. As plant tissues heat up, water is displaced from the cells and broken down into volatile gases. These gases can ignite plant fibers and create heat.
Fuel
The basic elements of a fuel for fire are its density, composition, and moisture content. Fuels are classified by their fire behavior, and a fire’s moisture content determines how quickly it spreads and how difficult it is to control. These factors are important in a firefighting strategy, and you should consult the manufacturer’s safety data sheet before using any fuel. Light fuels can quickly become a fire, and their density makes them ideal for igniting.
Oxygen
Fire and oxygen go hand in hand. The presence of fire on Earth is an important evolutionary event. The charcoal record shows that the three ingredients were present at least 420 million years ago. This timing provides some insight into the composition of the atmospheric oxygen, one of the “master variables” in the earth system. In fact, oxygen levels are changing as our planet warms. So how did oxygen and fire get together in the early days of the planet?
Heat
Fire is an example of an exothermic process, where the energy stored in chemical bonds is released as an electromagnetic wave. In the process of combustion, fuel and oxygen combine to form carbon dioxide and water. This reaction requires energy to start, and more energy is released once the atoms are bonded together. This is a key step in the formation of a fire. Fire extinguishers can control the fire at the ignition stage.
Convection
There are three ways that heat can spread during a fire. Direct contact, conduction, and evaporation. Each method uses different principles and objects to transmit heat. Direct contact is the fastest way to spread heat. Hot smoke travels in all directions. Then, hot air rises from the ground to the ceiling. Eventually, hot air ignites the suspended ceiling tiles and starts another fire. Convection is closely related to the spread of fire.
Color
There are many ways to change the color of fire, and pyrotechnics are a common way to do this. Fire performers use colored fire in fireworks and stage productions around the world. Colored fire can appear white, yellow, blue, or red, but the primary color of the flame is blackbody radiation from steam and soot. The colors can be controlled by adding other colors, such as glitter or smoke, and adjusting the amount of each.
Size
To determine the size of a fire, the Incident Commander and Fire Management Officer must first identify its characteristics. They must refer to local fire sizeup cards for guidance. Fire sizeups should consider the fuel type, potential for spread, weather conditions, and the resources available to fight the blaze. Once they’ve identified these characteristics, they should answer questions raised by incident commanders and repeat the analysis if conditions change. This way, they can ensure that they’re providing the best assistance possible to firefighters and other stakeholders.
Spread
The main cause of the slow spread of fire is the radiative heat transfer. The flames in this scenario are thin and of low emissivity. The bulk density of the fuel bed is the determining factor, which is also a factor in the deflection of the front of the burning fuel from the vertical. The Rpb cos o is constant for a large range of conditions and is in the order of 5-10 mg cm -2 s-1.