Metal ledgers and ribbons that are part of a patented scaffold system may be used when installed in accordance with the manufacturer's instructions. When metal ledgers are used or when ledgers are bolted or when a 45-degree angle brace is nailed to the uprights between double ledgers, and ledgers also nailed to this brace, the ribbon may be placed at other elevations such as guardrail height, but they cannot be eliminated from the scaffold. The ribbons shall be long enough to extend from upright to upright without splices. Interest has multiplied because the scaffold platform material is the weakest link of any temporary structure. The ribbons shall be 1-inch by 6-inch or heavier material, placed on the outer uprights, directly under, and in contact with, the ledgers. Scaffolding planks are widely used in the construction field as temporary platform support for. Vertical spacing of ribbons and ledgers shall not exceed 7 feet. Single 2-inch by 4-inch ledgers are not permitted. For ledgers spanning not more than 3 feet between uprights, use 2 pieces of 1-inch by 6-inch board, 1 being on each side of the uprights and fastened securely at each point of support. The platforms of the scaffold shall be supported by ledgers. Note:1 1/8-inch by 10-inch by 10-inch piece of exterior grade plywood may be used in lieu of the wooden base mentioned above. When the scaffold is resting on earth or other such material, the uprights shall rest on and be secured to the equivalent of a 2-inch by 10-inch by 10-inch wooden base. If the uprights of the scaffold rest on a surface that might cause slipping, a continuous sill or other means shall be provided to hold the uprights in place. The splices of uprights shall be made with square butt joints, and scabs of 1-inch by 4-inch or heavier material at least 48 inches long shall be nailed on 2 sides of each upright with 6 nails in each 1/2 of each scab. The inside uprights may be omitted and ledgers attached to the permanent structure, provided that the method of attaching the ledgers to the permanent structure will make the connection as secure as though the ledger were nailed to the upright with 5 8-penny nails. For heights not to exceed 20 feet, the uprights shall be 2-inch by 4-inch lumber or heavier, spaced not more than 3 feet between uprights at right angles to the wall and not more than 10 feet center to center, parallel to the wall.
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