----------

NOTES

Figure 1: Air movement into and out of a structure under normal conditions.

Prior to any fire development, every structure has air moving in and out of the structure through planned openings such as windows, doors, shafts, and HVAC systems, as well as through unplanned openings such as leakage in the building envelope due to ambient conditions. Multiple compartments, rooms, levels and potential openings will increase the complexity of the air movement. Recognizing potential flow paths and our ability to manage them will dictate our tactical ventilation plan, and, ultimately, how smoke, air, heat and flame move throughout the structure during a fire.