Safety requirements for scaffolding in Standards - 29 CFR 21
To be continued:
1910.28(g)(12)(ii)
Plank-type platforms shall be composed of not less than nominal 2 x 8-inch unspliced planks, properly cleated together on the underside starting 6 inches from each end; intervals in between shall not exceed 4 feet. The plank-type platform shall not extend beyond the hangers more than 18 inches. A bar or other effective means shall be securely fastened to the platform at each end to prevent its slipping off the hanger. The span between hangers for plank-type platforms shall not exceed 10 feet.
1910.28(g)(12)(iii)
Beam platforms shall have side stringers of lumber not less than 2 x 6 inches set on edge. The span between hangers shall not exceed 12 feet when beam platforms are used. The flooring shall be supported on 2- and 6-inch crossbeams, laid flat and set into the upper edge of the stringers with a snug fit, at intervals of not more than 4 feet, securely nailed in place. The flooring shall be of 1-x 6-inch material properly nailed. Floorboards shall not be spaced more than one-half inch apart.
TABLE D-17 - SCHEDULE FOR LADDER-TYPE PLATFORMS
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Length of platform (feet)
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12 14 & 16 18 & 20
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Side stringers,
minimum cross
section
(finished sizes):
At ends (in.)...... 1 3/4 x 2 3/4 1 3/4 x 2 3/4 1 3/4 x 3
At middle (in.).... 1 3/4 x 3 3/4 1 3/4 x 3 3/4 1 1/4 x 4
Reinforcing strip
(minimum)(1).......... ............. ............. ...........
Rungs(2).............. ............. ............. ...........
Tie rods:
Number (minimum)... 3 4 4
Diameter (minimum). 1/4 in 1/4 in 1/4 in
Flooring, minimum
finished size (in.).. 1/2 x 2 3/4 1/2 x 2 3/4 1/2 x 2 3/4
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TABLE D-17 - SCHEDULE FOR LADDER-TYPE PLATFORMS
[CONTINUED]
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Length of platform (feet)
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22 & 24 28 & 30
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Side stringers,
minimum cross
section
(finished sizes):
At ends (in.)...... 1 3/4 x 3 1 3/4 x 3 1/2
At middle (in.).... 1 3/4 x 4 1/4 1 3/4 x 5
Reinforcing strip
(minimum)(1).......... ............. .............
Rungs(2).............. ............. .............
Tie rods:
Number (minimum)... 5 6
Diameter (minimum). 1/4 in 1/4 in
Flooring, minimum
finished size (in.).. 1/2 x 3/4 1/2 x 2 3/4
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Footnote(1) A 1/8 x 7/8-in, steel reinforcing strip
or its equivalent shall be attached to the side or
underside full length.
Footnote(2) Rungs shall be 1 1/8-in. minimum, diameter
with at least 7/8-in. diameter tenons, and the maximum
spacing shall be 12 in. center to center.