Wind induced pressure differences have been measured across the exterior walls of 2 schools; one is surrounded by houses and trees and the other is partially shielded from wind. These schools were selected from a total of 11 schools whose air leakage characteristics had been previously studied.

The measured pressure differences across the exterior walls were analyzed and the corres­ponding air infiltration rates were calculated. These were used to evaluate the equivalent uniform pressure differentials caused by wind. Similarly, the equivalent uniform pressure differentials caused by stack action were also calculated using a computer model. It was shown that these equivalent pressure differentials could be summed and used with the air leakage data obtained by fan pressurization method to predict air infiltration rates for schools under various conditions of wind and stack action.