From :
The classification is particularly important. If a building has a dominant opening (like a garage door or breached window) on the windward side, it can become partially enclosed. This creates a "ballooning" effect where internal pressure combines with external suction on the leeward wall, drastically increasing the net load on the structure. Engineers must consider scenarios where windows might break during a storm, potentially changing the building's classification during a wind event. wind load calculation as per asce 7-05
Before any calculation, the engineer must determine the following from Chapter 6: From : The classification is particularly important