When you open a door and the smoke exits through the top half of the doorway and clean air enters through the bottom half, the fire is probably on which level?

When observing smoke exiting through the top half of a doorway while clean air is entering through the bottom half, this indicates a phenomenon known as smoke stratification. Smoke is typically hotter than the surrounding air, causing it to rise. If smoke is escaping from the top of the doorway, it suggests that the fire is likely located at the same level as the door, producing smoke that is accumulating and escaping upwards.

This scenario demonstrates that smoke is being pushed out due to the heat generated by the fire, creating a negative pressure situation that allows clean air to be drawn in from below. Consequently, the fire must be at a level where it’s generating significant heat and smoke that collects near the ceiling of that same level.

Understanding this behavior is critical for firefighters as it informs their tactics in approaching a fire situation. Recognizing the location of the fire can help firefighters determine the safest and most effective way to conduct ventilation, search and rescue operations, and firefighting efforts.