Where do air flows exert suction in buildings during the stack effect?

During the stack effect, air flows tend to exert suction at the lower levels of a building. The stack effect occurs due to the temperature differences between the inside and outside air, particularly in multi-story buildings. Warm air rises because it is less dense, creating a pressure difference within the building.

As the warm air moves upward, it creates a partial vacuum or lower pressure at the lower levels or the basement areas of the building. This suction can pull in cooler air from the outside through openings at the lower levels, such as doors, windows, or vents. The air flow can also cause drafts that influence comfort levels within those spaces.

This understanding of the stack effect is vital for building analysts as it relates to thermal comfort, energy efficiency, air quality, and the overall performance of a building. Recognizing where suction occurs helps in designing effective ventilation strategies and in preventing issues like unwanted air infiltration that could impact heating and cooling loads.