(a) Every permitted use requiring the receipt or distribution by vehicles of materials or merchandise and having a floor area of 10,000 square feet or more shall have at least one permanently maintained offstreet loading space for each 10,000 square feet or fraction thereof of gross floor area.

(b) Single-occupancy retail operations, wholesale operations and industrial operations with a gross floor area of less than 10,000 square feet shall provide sufficient receiving space on the property so as not to hinder the movement of vehicles and pedestrians over a sidewalk, street or alley.