No building or structure shall be erected, reconstructed or structurally altered to exceed the height limit herein established for the zone in which such building is located, unless otherwise specifically stated in the underlying zone.  Structures for the housing of elevators, stairways, tanks, ventilating fans or similar equipment required to operate and maintain the buildings, and fire or parapet walls, skylights, flagpoles, chimneys, smokestacks or similar projections may be erected above the height limits prescribed in the underlying zone; provided the projections are permitted uses in the underlying zone, and the projection does not exceed the height limit by more than eight (8) feet.  Religious institution steeples or similar structures may exceed this eight (8)-foot limit if approved by a conditional use permit.  No projection, structure or any space above the height limits shall be allowed for the purpose of providing habitable floor space.  Tanks, ventilating fans, and similar utility and mechanical equipment shall be screened as set forth in Chapter 18.38 (Supplemental Use Regulations).  (Ord. 5920 § 1 (part); June 8, 2004.)