Dear 100 Hour Board,
The building in which I work has three wings. One wing was built in 2000 while the other two wings date from the late 1960s. During winter, there's often a big air-pressure difference between the new wing and the rest of the building. When one opens a door between the new wing and the rest of the building (these doors are usually closed), there's always a wind, which is sometimes quite strong and it always blows from the new wing into the old wings. The wind is strongest on the uppermost floors of the stairwell. What might cause this phenomenon?
--Kitty the Badger
Fans. Big ones.
No, I'm not kidding! I've noticed that many times newer buildings have better systems for air circulation, and the fans that drive those air systems causes a pressure difference. That may not be the case in your particular building, but I'd say it's a distinct possibility.
- Big BYU fan