All projecting signs subject to the sign regulations shall meet the following requirements:
1. All bracing systems shall be designed and constructed to transfer lateral forces to the foundations. For signs on buildings, the dead and lateral loads shall be transmitted through the structural members of the building to the ground in such manner as not to overstress any of the elements thereof.
2. The letter or advertising design to be illuminated on projecting signs may be composed of glass or other transparent or semitransparent material. Any glass forming a part of any sign shall be safety glass or wire glass.
3. Any movable parts of a projecting sign such as a cover of a service opening shall be securely fastened by safety chains or hinges.
4. The top line of the projecting sign shall not by higher than the roof or parapet line of the building to which attached, except that when the roof line is less than 15 feet in height, the sign may extend 3 feet above; but under no circumstances shall the top line of a projecting sign be permitted at a height of more than 50 feet above ground level.
5. The distance measured between the principal faces of any projecting sign shall not exceed 18 inches.
6. The bottom line of every projecting sign shall be placed at least 10 feet above any sidewalk over which it is erected.
7. No projecting signs shall be erected in any alley.
8. No projecting signs shall project across or over any portion of public right-of-way.