Which condition will most likely cause smoke to stratify in a large building?

The condition that most likely causes smoke to stratify in a large building is typically associated with the winter stack effect. When a large building is heated, the warmer air inside rises and creates a pressure differential, causing cooler outside air to be drawn in through lower openings. This phenomenon can lead to the stratification of smoke in a fire scenario as the warm smoke rises and accumulates at higher levels within the building.

In contrast, a fire in the decay phase has typically diminished in intensity, resulting in reduced smoke production and less likelihood of noticeable stratification. While a sprinkler system activation can also affect smoke movement by suppressing the fire and lowering the heat, it does not primarily cause smoke stratification. A ventilation-controlled fire, on the other hand, may involve specific smoke movement patterns, but in terms of stratification, the stack effect plays a more significant role due to the differential heating and air pressure conditions in large structures.