The following types of structures or structural parts are not subject to the building height limitations of this chapter: chimneys, cupolas, tanks, church spires, belfries, domes, derricks, monuments, fire and hose towers, observation towers, transmission towers, smokestacks, flagpoles, radio, cellular and television towers, masts, aerials, cooling towers, water towers, elevator shafts, windmills, conveyors, mill related apparatus and other similar projections.