Notwithstanding any other provisions of this chapter, flagpoles are a flagpole is an accessory structure and shall be permitted in any yard in any zone, provided and that a principal use and/or principal structure exists on the property. A flagpole shall have a maximum height of 25 feet provided that any such pole and shall not be closer to a property line or street right-of-way line than the height of the pole or 20 feet, whichever is greater. No such flagpole shall be erected unless approved by the Building Inspector as to its structural stability and its ability to withstand maximum anticipated wind forces.