TrickyRicky
Senior Member
I'm not very familiar with how HVAC and air handling systems are designed to compensate against the phenomenon but I could add a few points of general interest. All buildings experience "stack effect". This is an air pressure gradient resulting from the bouyancy of hot air relative to cold. The building essentially acts like a chimney. This phenomenon is accentuated in tall buildings where there is a higher gradient from the bottom to the top. Air gets sucked in to the lower portion of the building and is blasted out at the top. So if there was no control of this phenomenon a person at the base of the building opening a door would feel themselves getting sucked into the building while a person at the top opening a window would feel themselves being sucked out. Somewhere in the middle is a line called the neutral pressure plane where a person opening the window would experience no air movement at all. As I understand the elevator shafts are the primary regulators maintaining a more balanced pressure from floor to floor.