Each loading berth shall be not less than forty-five (45) feet in length and twelve (12) feet in width exclusion of aisle or maneuvering space, and shall have an overhead clearance of not less than fourteen (14) feet, except that for mortuaries, cemeteries, mausoleums and crematories, a loading berth used exclusively for ambulances or hearses shall not be less than twenty-four (24) feet in length and ten (10) feet in width and shall have an overhead clearance of not less than eight (8) feet.