Which statement best describes the flow path concept?

• A. It describes the movement of heat and smoke from low-pressure to high-pressure areas.
• B. It describes the movement of heat and smoke toward exterior only.
• C. It describes the movement of heat and smoke from high-pressure areas toward lower-pressure areas accessible via doors.
• D. It describes the path of sound through the structure.

Answer: (C)

The flow path concept describes how heat and smoke move inside a burning structure due to pressure differences and the openings that connect spaces. As a fire grows, the fire area becomes a high‑pressure source of hot gases, which pushes toward lower‑pressure areas through openings like doors and windows. The path these gases follow—the flow path—often runs from the fire room toward adjacent spaces or toward the exterior, wherever a connection (door, window, or other opening) provides a route. Doors and openings are key because they create and shape that conduit, and when they’re open, they allow fresh air to feed the fire, accelerating the movement of heat and smoke along the path. This concept helps predict where heat and smoke will travel, guiding ventilation, search, and suppression decisions.