No sign or its supporting members shall be erected, altered or relocated so as to interfere with or restrict access to a window or other opening in a building in such manner as to unduly limit air circulation or obstruct or interfere with the free use of a fire escape, exit, standpipe, stairway, door, ventilator or window or similar opening, provided, however, that the director of building inspections may approve a swinging sign or other form of sign or its attachment, when, in his or her judgment, such sign will not restrict access to such openings. (Prior code § 3.05.084)