Aisles shall be provided in all stands; Except, that aisles may be omitted when all the following conditions exist: Seats are without backrests; the rise from row to row does not exceed 300 millimeters per row; the number of rows does not exceed eleven (11) in height; the top seating board is not over 3.00 meters above grade; and the first seating board is not more than 500 millimeters above grade.