Which factor most directly affects how much ambient air is entrained into a plume during the growth stage?

• A. Location of fuel package
• B. Type of fuel
• C. Ignition location
• D. Ventilation rate

Answer: (A)

In the growth stage, how much ambient air a rising plume can draw in is driven by the plume’s geometry set by where the heat is released. The location of the fuel package determines the initial rise path of the plume and how it interacts with walls, openings, and the room’s boundaries. This shapes the boundary through which air can be entrained, so changing the fuel’s position directly alters how much ambient air is pulled into the plume. While the fuel type, ignition location, and overall ventilation rate can influence fire behavior in other ways, they don’t control the plume’s entrainment boundary as directly as where the heat release occurs.