12 CRR-NY 23-5.9NY-CRR
12 CRR-NY 23-5.9
12 CRR-NY 23-5.9
23-5.9 Two-point suspension scaffolds.
(a) Width and fastening.
Two-point suspension scaffold platforms shall be not less than 20 inches nor more than 32 inches in width. Every such platform shall be of sufficient width to properly fit the hangers and shall be securely fastened thereto by U-bolts which pass around the hangers or by other equivalent means.
(b) Hangers.
The platforms of two-point suspension scaffolds shall rest on hangers fabricated of mild steel or wrought iron, each having a cross-sectional area capable of sustaining four times the maximum rated load. Such hangers shall be designed with supports for guard rails, intermediate rails and toeboards.
(c) Roof irons.
Roof irons or hooks used in connection with two-point suspension scaffolds shall be constructed of mild steel or wrought iron and shall be securely anchored. They shall be provided with tie-backs of at least three-quarters inch manila rope so installed that the tension is at right angles to the face of the building or other structure. Where the upper block hook does not directly engage the roof iron, the connection shall be made by improved plow steel wire rope not less than one-half inch in diameter.
(d) Safety railings and screening.
The open sides of two-point suspension scaffolds shall be provided with safety railings constructed and installed in compliance with this Part (rule). In addition, such safety railings shall be provided with wire mesh installed from the toeboards to the top railings. Such wire mesh shall be not less than No. 18 U.S. gage steel with openings that will reject a one-inch diameter ball.
(e) Use of two-point suspension scaffolds.
(1) Two or more such scaffolds shall not be combined into one by bridging the distance between them. Persons shall not pass from one two-point suspension scaffold to another. Not more than two persons shall be permitted to work on any two-point suspension scaffold at one time unless such scaffold is specially approved and such use is stated in such approval.
(2) Every person located on any two-point suspension scaffold shall be provided with and shall be required to use an approved safety belt or harness together with a separate hanging lifeline in compliance with this Part (rule).
(f) Suspension ropes.
(1) When hoisting machines are used for any two-point suspension scaffold, the wire rope shall be at least five-sixteenths inch in diameter and capable of supporting at least six times the intended load.
(2) All fibre rope used for two-point suspension scaffolds shall be at least equivalent in strength to three-quarter inch first grade manila rope.
(g) Platform requirements.
Wood platforms of two-point suspension scaffolds shall comply with one of the following requirements. Metal platforms or other platforms not in compliance with this Part (rule) shall be approved.
(1) Ladder type platforms.
(i) The side stringers of the horizontal supporting ladder shall be constructed of clear spruce or other material of equivalent strength and durability. The rungs shall be constructed of straight-grained oak, ash or hickory not less than one and one-eight inches in diameter with seven-eights inch tenons mortised into the side stringers at least seven-eights of an inch. The stringers shall be tied together with metal tie rods not less than one-quarter inch in diameter. Such tie rods shall pass through the stringers and shall be riveted tight against washers at both ends. Hangers shall be securely fastened to the platforms not less than six inches nor more than 18 inches from either end by means of U-bolts at the bottom supporting member. Such U-bolts shall pass over the side rails of the platforms. (See Tables XII and XIII of this Subpart.)
(ii) The flooring strips of ladder type platforms shall be spaced so that any opening in the platform floors will reject a three-quarter inch diameter ball. Ladder type platforms shall be constructed in accordance with the schedules listed in Tables XII and XIII of this Subpart.
(2) Plank type platforms.
Plank type platforms shall be constructed of planks not less than two inches in thickness and eight inches in width, full size. Such planks shall extend not less than six inches nor more than 18 inches beyond the supporting hangers. A bar shall be nailed across the platform on the underside at each end to prevent the platform from slipping off the hangers. Where two or more planks are used, they shall be fastened together by cleats not less than one inch by six inches in size. Such cleats shall be nailed on the underside at intervals of not more than four feet. Planks used for such platforms shall not be spliced. Any span between supports shall not exceed 10 feet.
(3) Beam platforms.
Beam platforms shall have stringers constructed of straight-grained lumber not less than two inches by six inches full size set on edge. The stringers shall be supported on the hangers and the clear spans between hangers shall not exceed 16 feet. The ends of the stringers shall extend beyond the hangers not less than six inches nor more than 18 inches. The stringers shall be bolted to the hangers by means of U-bolts which pass around the hangers and through the stringers. The platforms shall be supported on cross-beams not less than two inches by six inches full size which are laid flat and let into the upper edges of the stringers at intervals of not more than four feet. Such cross-beams shall fit snugly and shall be securely nailed in place with screw-type nails. The platforms shall be constructed of lumber not less than one inch by six inches in size, nailed tight together and extended to the outside faces of the stringers. The ends of all platform boards shall rest on the cross-beams and shall be securely nailed thereto.
TABLE XII SCHEDULE FOR LADDER TYPE PLATFORMS
| Platform Length (Feet) | 12 | 14 & 16 | 18 & 20 | 22 & 24 | 28 & 30 |
|---|---|---|---|---|---|
| Side Stringers—Minimum Cross–Section (Finished Sizes—Inches) | |||||
| (a) At Ends | 1¾ × 2¾ | 1¾ × 2¾ | 1¾ × 3 | 1¾ × 3 | 1¾ × 3½ |
| (b) At Middle | 1¾ × 3¾ | 1¾ × 3¾ | 1¾ × 4 | 1¾ × 4¼ | 1¾ × 4¼ |
| Reinforcement (Minimum) | A ⅛–in. × ⅞–in. steel reinforcing strip or its equivalent shall be attached to the underside, full length. | ||||
| Rungs | Rungs shall be 1 ⅛ inches minimum diameter with at least ⅞–in. diameter tenons, and the maximum spacing shall be 18 inches, center to center. | ||||
| Tie Rods— | |||||
| (a) Number (Minimum) | 3 | 4 | 4 | 5 | 6 |
| (b) Diameter | Minimum diameter—¼–in. | ||||
| Flooring | The minimum finished size of flooring shall be ½–in. × 2¾–in. | ||||
| Materials | |||||
| Side Rails | Clear sitka spruce; west coast hemlock; Douglas fir. | ||||
| Rungs | Straight grain hickory, ash or oak | ||||
TABLE XIII SCHEDULE FOR LADDER TYPE PLATFORMS FOR EXTENSION TRESTLE AND TRESTLE SCAFFOLDS
| Platform Length (Feet) | 10–14 | 16 | 18–20 | 22–24 | 26–28 |
|---|---|---|---|---|---|
| Cross–Section (Inches)— | |||||
| Tapered — Ends | 1⅜ × 3 | 1⅜ × 3¼ | 1⅜ × 3½ | 1⅜ × 3½ | — |
| Middle | 1⅜ × 3 | 1⅜ × 3¼ | 1⅜ × 3¾ | 1⅜ × 4½ | — |
| No Taper | 1⅜ × 3 | 1⅜ × 3¼ | 1⅜ × 3½ | 1⅜ × 4 | 1⅜ × 4¼ |
| Reinforcement | A 1⅛–in. × ⅞–in. steel reinforcing strip or its equivalent shall be attached to the underside of each side rail, full length. | ||||
| Rungs | Rungs shall be 1–3/16 inches minimum diameter with at least ⅞–in. diameter tenons, and the maximum spacing shall be 14 inches, center to center. | ||||
| Tie Rods | 5/16–in. diameter spaced at every fourth rung. | ||||
| Flooring | Minimum finished flooring size:½–in. × 1 ⅝–in. | ||||
| Materials | |||||
| Side Rails | Clear sitka spruce; west coast hemlock; Douglas fir. | ||||
| Rungs | Straight grain hickory, ash or oak. | ||||
12 CRR-NY 23-5.9
Current through March 15, 2022
| End of Document |