Section 6.21. Crawling boards or chicken ladders

(a) Construction. Crawling boards shall be at least 10 inches in width and not less than 1 inch thick. The cross strips shall be as long as the width of the board, at least 1 1/2 inches wide and not less than 1 inch thick.

(b) Fastenings. Where crawling boards are double, they shall be securely bolted together by a hinge bolt, with the hinge resting on the peak or ridgepole of the roof. Where single, they shall be provided with hooks, bolts or solidly fastened cleats on the underside of the board at the upper end, so arranged as to hook or catch over the peak or ridgepole of the roof. If bolts or cleats are used, the upper end of the board shall also be nailed to the roof to prevent the board from slipping in an upward direction, thus disengaging the hold.

(c) Protection. When crawling boards are used on roofs where the slope is more than 6 inches in 1 foot, a catch platform or lifelines shall be used.