Fire Tetrahedron
The fire tetrahedron or combustion tetrahedron is a simple model for understanding the necessary ingredients for most fires.[1]
The tetrahedron illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elements are present and combined in the right mixture,[2] meaning that fire is actually an event rather than a thing. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle. For example, covering a fire with a fire blanketremoves the oxygen part of the triangle and can extinguish a fire.
Consider, for example, how firecrackers create explosions. The fuse burns in the center of a firecracker. The powder surrounds it ignites and the heat produces vapours. The paper wrapped around the firecracker cannot contain the expanding gases and the fire cracker explodes.