By how much can a baffle reduce the required free area of an opening to prevent rain entry?

A baffle can significantly contribute to the prevention of rain entry through openings by effectively redirecting the flow of water. The design and placement of a baffle can serve to deflect rainwater away from the opening, thus enhancing the overall performance of the system in keeping water out.

In certain situations, a well-designed baffle can entirely eliminate the need for an increase in the free area of an opening to prevent rain entry, resulting in a 0% requirement for additional free area. This indicates that no additional area is necessary when a baffle is properly utilized; the existing opening is sufficient because the baffle is effectively managing the rain's impact. Therefore, the correct answer reflects the efficiency of baffles in controlling water ingress without necessitating other modifications to the openings.