What does "failure to account for ... pressurization due to door or window failures" mean? (Page 14/55 - 5th bullet item)

The wind uplift resistance design of the roofing system is based on a number of variables including ground roughness, orientation, height, wind speed as well as whether the building is "enclosed", "partially enclosed" or "open". Intact windows and doors are required to consider a building to be "enclosed". If the doors or windows were to fail, or be blown in, the interior building pressure could build up and more uplift pressure would be exerted on the roof than what results from the wind blowing over the roof. Storm shutters and impact resistant glass can be considered to assure the windows and doors stay intact.