A loading space shall have minimum dimensions of not less than twelve (12) feet in width, fifty (50) feet in length, exclusive of driveways, aisles, and other circulation areas, and a clearance height of not less than fifteen (15) feet. One off-street loading space shall be provided and maintained on the same lot requiring delivery of goods and having a modified gross floor area of up to five thousand (5,000) square feet. One loading space shall be provided for each additional ten thousand (10,000) square feet or fraction thereof of ground floor area.