Penthouses or roof structures for the housing of elevators, stairways, tanks, ventilating fans, air conditioning equipment or similar equipment required to operate and maintain the building, fire or parapet walls, skylights, flagpoles, or water tanks, or may be erected above the height limits prescribed in this chapter, provided that such equipment or structures do not occupy more than 25% of the total roof area and is screened in accordance with § 192-46.