As defined earlier, the ventilation profile is the appearance of the entire fire building's ventilation openings, showing the flow paths of any air movement into the structure as well as smoke, heat or flame out of the structure.

Air movement occurs in structures regardless of whether there is fire involvement. Air moves in and out due to planned openings such as windows, doors, shafts, and HVAC systems, as shown in Figure 1 and Figure 2.

Unplanned openings such as leakage in the building envelope also result in air movement due to ambient conditions. Multiple compartments, rooms, levels, and potential openings will increase the complexity of the air movement. Recognizing and managing potential flow paths will dictate the tactical ventilation plan and ultimately, how smoke, air, heat and flame move throughout the structure during a fire, as shown in Figure 3.