What direction does the ambient air flow in the intake of a structure fire?

Ambient air flows toward the seat of the fire due to the heat generated by the flames. As a fire burns, it consumes oxygen and creates hot gases that rise, creating a low-pressure area around the fire. This phenomenon is influenced by the principles of convection and the natural tendency of hot air to rise. The cooler ambient air in the surrounding environment is drawn in to replace the oxygen that is being consumed by the fire, thereby feeding it.

This movement of air towards the fire is critical for its survival and growth and illustrates the importance of understanding airflow dynamics in firefighting operations. Recognizing that ambient air flows toward the seat of the fire helps firefighters strategize their approach, ensuring that they can address ventilation needs effectively and prevent the fire from spreading.