1926.451 Scaffolding

(a) General Requirements.

(1) Scaffolds shall be erected in accordance with requirements of this section.

(2) The footing or anchorage for scaffolding shall be sound, rigid, and capable of carrying the maximum intended load without settling or displacement. Unstable objects such as barrels, boxes, loose brick, or concrete blocks, shall not be used to support scaffolds or planks.

(3) No scaffold shall be erected, moved, dismantled, or altered except under the supervision of competent persons.

(4) Guardrails and toe boards shall be installed on all open sides and ends on platforms more than 10 feet above the ground or floor, except needle beam scaffolds and floats (see paragraph (p) and (w) of this section). Scaffolds 4 feet to 10 feet in height, having a minimum horizontal dimension in either direction of less than 45 inches, shall have standard guardrails installed on all open sides and ends of the platform.

(5) Guardrails shall be 2 x 4 inches, or the equivalent, approximately 42 inches high, with a mid-rail, when required. Supports shall be at intervals not to exceed 8 feet. Toe boards shall be a minimum of 4 inches in height.

(6) Where persons are required to work or pass under a scaffold, scaffolds shall be provided with a screen between the toe board and the guard rail, extending along the entire opening, consisting or No. 18 gauge U.S. Standard wire 1 /2 inch mesh, or the equivalent.

(7) Scaffold and their components shall be capable of supporting without failure at least 4 times the maximum intended load.

(8) Any scaffold including accessories such as braces, brackets, trusses, screw legs, ladders, etc. damaged or weakened from any cause shall be immediately repaired or replaced.

(9) All load-carrying timber members of scaffold framing shall be a minimum of 1500 fiber (Stress Grade) construction grade lumber. All dimensions are nominal sizes as provided in the American Lumber Standards, except where rough sizes are noted, only rough or undressed lumber of the size specified will satisfy minimum requirements.

(10) All planking shall be Scaffold grades, or equivalent, as recognized by approved grading rules for the species of wood used. The maximum permissible spans for 2 x 10 inch or wider planks shall be as shown in the following:

(11) The maximum permissible span for 1-1/4 x 9 inch or wider plank of full thickness shall be 4 feet with medium duty loading of 50 p.s.f.

(12) All planking of platforms shall be overlapped (minimum 12 inches), or secured from movement.

(13) An access ladder or equivalent safe access shall be provided.

(14) Scaffold planks shall extend over their end supports not less than 6 inches nor more than 12 inches.

(15) The poles, legs, or uprights, of scaffolds shall be plumb, and securely and rigidly braced to prevent swaying and displacement.

(16) Overhead projection shall be provided for men on a scaffold exposed to overhead hazards.

(17) Slippery conditions on scaffolds shall be eliminated as soon as possible after they occur.

(18) No welding, burning, riveting, or open flame work shall be performed on any staging suspended by means of fiber or synthetic rope. Only treated or protected fiber or synthetic rope shall be used for or near any work involving the use of corrosive substances or chemicals. Specific requirements for boatswain's chairs and float or ship scaffolds are contained in paragraphs (1) and (w) of this section.

(19) Wire, synthetic, or fiber rope used for scaffold suspension shall be capable of supporting at least 6 times the rated load.

(20) The use of shore or lean-to scaffolding is prohibited.

(21) Lumber sizes, when used in this subpart, refer to nominal sizes except where otherwise stated.

(22) Materials being hoisted on to a scaffold shall have a tag line.

(23) Employees shall not work on scaffolds during storms or high winds.

(24) Tools, materials, and debris shall not be allowed to accumulate in quantities to cause a hazard.

(m) Carpenters' bracket scaffolds.

(1) The brackets shall consist of a triangular wood frame not less than 2 x 3 inches in cross section, or of metal or equivalent strength. Each member shall be properly fitted and securely joined.

(2) Each bracket shall be attached to the structure by means of one of the following:

(i) A bolt, no less than five eighths inch in diameter, which shall extent to the inside of the building wall;

(ii) A metal stud attachment device;

(iii) Welded to steel tanks;

(iv) Hooking over a well secured and adequately strong supporting member.

(3) The brackets shall be spaced no more than eight feet apart.

(4) No more than two employees shall occupy any given 8 feet of a bracket scaffold at any one time. Tools and materials shall not exceed 75 pounds in addition to the occupancy.

(5) The platform shall consist of not less than two 2 x 10 inch nominal size planks extending not more than 12 inches or less than 6 inches beyond each support.

(6) Guard rails made of lumber, not less than 2 x 4 inches (or other material providing equivalent protection), approxi mately 42 inches high, with a mid-rail, of 1 x 6 inch lumber (or other material providing equivalent protection), and toe boards, shall be installed at all open sides and ends of all scaffolds more than 10 feet above the ground or floor. Toe boards shall be a minimum of 4 inches in height. Wire mesh shall be installed in accordance with paragraph (a)(6) of this section.

(s) Ladder jack scaffolds.

(1) All ladder jack scaffolds shall be limited to light duty and shall not exceed a height of 20 feet above the floor or ground.

(2) All ladders used in connection with ladder jack scaffolds shall be heavy duty ladders and shall be designed and constructed in accordance with American National Standards Institute A 14.1-1968, Safety Code for Portable Wood Ladders, and A 14.2-1968, Safety Code for Portable Metal Ladders. Cleated ladders shall not be used for this purpose.

(3) The ladder jack shall be so designed and constructed that it will bear on the side rails in addition to the ladder rungs, or if bearing on rungs only, the bearing area shall be at least 10 inches on each rung.

(4) Ladders used in conjunction with ladder jacks shall be so placed, fastened, held, or equipped with devices so as to prevent slipping.

(5) The wood platform planks shall be not less than 2 inches nominal thickness. Both metal and wood platform planks shall overlap the bearing surface not less than 12 inches. The span between supports for wood shall not exceed 8 feet. Platform width shall not be less than 18 inches.

(6) Not more than two employees shall occupy any given 8 feet of any ladder jack scaffold at any one time.

(u) Roofing brackets.

(1) Roofing brackets shall be constructed to fit the pitch of a roof.

(2) Brackets shall be secured in place by nailing in addition to the pointed metal projections. When it is impractical to nail brackets, rope supports shall be used. When rope supports are used, they shall consist of first grade manila of at least 3/4 inch diameter, or equivalent.

(3) A catch platform shall be installed below the working area of roofs more than 16 feet above the ground to eaves with a slope greater than 4 inches in 12 inches without a parapet. In width, the platform shall extend 2 feet beyond the projection of the eaves and shall be provided with a guardrail, mid-rail, and toe board. This provision shall not apply where employees engaged in work upon such roofs are protected by a safety belt attached to a lifeline.

(y) Pump jack scaffolds.

(1) Pump jack scaffold shall:

(i) Not carry a working load exceeding 500 pounds; and

(ii) Be capable of supporting without failure at least four times the maximum intended load.

(iii) The manufactured components shall not be loaded in excess of the manufacturers recommended limits.

(2) Pump jack brackets, braces, and accessories shall be fabricated from metal plates and angles. Each pump jack bracket shall have two positive gripping mechanisms to prevent any failure or slippage.

(3) The platform bracket shall be fully decked and the planking secured. Planking, or equivalent, shall conform with paragraph (a) of this section.

(4)(i) When wood scaffold planks are used as platforms, poles used for pump jacks shall not be spaced more than 10 feet center to center. When fabricated platforms are used that fully comply with all other provisions of this para graph (y), pole spacing may exceed 10 feet center to center.

(4)(ii) Poles shall not exceed 30 feet in height.

(4)(iii) Poles shall be secured to the work wall by rigid triangular bracing, or equivalent, at the bottom, top, and other points as necessary, to provide a maximum vertical spacing of not more than 10 feet between braces. Each brace

shall be capable of supporting a minimum of 225 pounds tension or compression.

(4)(iv) For pump jack bracket to pass bracing already installed, an extra brace shall be used approximately 4 feet above the one to be passed until the original brace is reinstalled.

(5) All poles shall bear on mud sills or other adequate firm foundations.

(6) Pole lumber shall be two 2 x 4's, of Douglas fir, or equivalent, straight grained, clear, free of cross-grain, shakes, large loose or dead knots, and other defects which might impair strength.

(7) When poles are constructed of two continuos lengths, they shall be two by fours, spiked together with the seam parallel to the bracket, and with 10d common nails, no more than 12 inches center to center, staggered uniformly from opposite outside edges.

(8) If two by fours are spliced to make up the pole, the slices shall be so constructed as to develop the full strength of the member.

(9) A ladder, in accordance with 1926.1053, shall be provided for access to the platform during use.

(10) Not more than two persons shall be permitted at any one time upon a pump jack scaffold between any two supports.

(11) Pump jack scaffolds shall be provided with standard guard rails as defined in 1926.451(a)(5), but no guard rail is required when safety belts with lifelines are provided for employees.

(12) When a work bench is used at an approximate height of 42 inches, the top guard rail may be eliminated, if the work bench is fully decked, the planking secured, and is capable of withstanding 200 pounds pressure in any direction.

(13) Employees shall not be permitted to use a work bench as a scaffold platform.