The fire tetrahedron is a model that explains the four essential elements needed for a fire to ignite and sustain. These elements are heat, fuel, oxygen, and a chemical reaction. When all four components are present, a fire can start and continue to burn. Removing any one of these elements will extinguish the fire. This concept expands on the traditional fire triangle, which includes only heat, fuel, and oxygen. The addition of the chemical reaction highlights the importance of the combustion process in fire behavior. Understanding the fire tetrahedron is crucial for effective fire prevention and safety measures.