An air cooled condensing unit is located in a room that is 9`- 5″ x 5` with an 8` ceiling. A permanent opening to the outside of the building is required so ventilation air can be supplied to the mechanical room. What minimum net free area is required for the mechanical room`s vent opening?

An air cooled condensing unit is located in a room that is 9`- 5″ x 5` with an 8` ceiling. A permanent opening to the outside of the building is required so ventilation air can be supplied to the mechanical room. What minimum net free area is required for the mechanical room`s vent opening?