The height limitations contained in the zoning standards tables listed in Chapter 17.60 SMC shall not apply to spires, belfries, cupolas, chimneys, elevator machine rooms, elevator shafts, antennas, water tanks, ventilators, roof mechanical penthouses solely for air handling equipment, or other appurtenances usually required to be placed above the roof level and not intended for human occupancy; however, the heights of these structures or appurtenances thereto shall not exceed any height limits prescribed by airspace height zones. Additionally, the height requirements shall not apply to an elevator shaft as stated above; provided, that said elevator shaft does not occupy more than 20 percent of the roof of the building on which it is located. (Ord. 1294 § 8, 2011; Ord. 929 Ch. 6(I), 1995).