All fires need three things: heat, fuel, and oxidation. Heat is needed to accelerate particles in order to provide energy. Heat can be provided through friction; for example, two sticks rubbing together can provide a source of heat.

Fuel is another essential part of the fire triangle. When a fire runs out of fuel, the fire will burn itself out. Fires change the fuel chemically. Fuels burn differently according to their physical and chemical structures. Fossil fuels burn differently according to the structure of the carbon within them. The best fuels are dry—for example, forest fires often take place during the summer due to the abundance of dry leaf litter on the forest floor. Seasoned wood also burns hotter than wood harvested from a freshly cut tree.

Oxygen is the final component of the fire triangle. An abundance of oxygen is necessary for a large fire. If one wants to burn wood faster, it is best to use smaller pieces in order to increase the surface area. By increasing the surface area of the fuel, one increases its exposure to oxygen. Forest fires often get out of control on windy days due to the abundance of oxygen. Oxygen is also a vital factor in silo explosions that happen due to an abundance of dust. Without enough oxygen, fires will not consume the fuel completely.