Nonresidential site development and subdivision signs are allowed in the form of one wall-mounted or freestanding sign, erected at the development/subdivision entrance from a street. The sign shall not exceed 15 square feet, and may bear decorative or logo devices, but no commercial advertisement. For nonresidential site development, the sign shall not be erected prior to the issuance of a building permit and shall be removed upon completion of construction or the issuance of a certificate of occupancy, whichever comes first. For subdivisions, the sign shall not be erected prior to the commencement of construction activities and shall be removed upon the issuance of the first certificate of occupancy or the issuance of certificates of occupancy for 25% of the development, whichever comes later. Signs shall be removed if construction activities have halted for a period of 6 months and may be reinstalled with approval of the Building Commissioner or designee. Signs required from federal, state, and/or local permitting authorities are excluded from the provisions of this section.