OSHA Construction · Part 9: Stairways, Ladders, Confined Spaces and Scaffolds
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9.3 Scaffolds
A scaffold is any temporary elevated platform that supports workers, materials or both. It gives support and balance to a worker who has to reach places that are difficult or impossible to reach otherwise. Scaffolds are used in building, shipbuilding and by window cleaners on tall buildings.
Types
- Supported scaffolds have one or more platforms on poles, frames and beams that stand on solid ground. Rules for the frame or fabricated scaffold apply to other supported types unless stated.
- Suspended scaffolds hang from ropes attached to a fixed overhead structure. Rules for the two point scaffold apply to other suspension types unless stated.
| Term | Meaning |
|---|---|
| Bearer (putlog) | A horizontal member that supports the platform and joins the uprights. |
| Brace | A rigid link that holds one member in position against another member or the structure. |
| Coupler | A device that locks together the tubes of a tube and coupler scaffold. |
| Outrigger | A structural member that widens the base of a supported scaffold for stability. |
| Outrigger beam (thrustout) | A member of a suspension scaffold that extends the point of attachment out and away from the building. |
| Boatswain's chair | A single point adjustable suspension scaffold with a seat or sling for one person. |
| Crawling board (chicken ladder) | A plank with cleats for footing on sloping surfaces such as roofs. |
| Maximum intended load | The total of all people, equipment, tools, materials and other loads reasonably expected to be on the scaffold at one time. |
Reducing the risk
One in every three construction deaths results from a fall. A scaffold worker must be protected against falls when working at more than 10 feet above a lower level. Space on a scaffold is limited, and materials take up much of it.
Uniformity.
- Build the scaffold as the manufacturer instructs.
- Do not alter or modify any components. If there is a problem, contact the manufacturer.
- Never mix and match components from different manufacturers.
- Never use different metals for the components of a scaffold.
Other essentials.
- A competent person designs, supervises the erection of and inspects the scaffold, and a qualified person designs it where required.
- Each scaffold and its parts must support at least four times the maximum intended load. Suspension ropes must support at least six times.
- Footing must be sound and rigid, with base plates and mud sills where needed. Never use unstable objects such as bricks or barrels to support a scaffold.
- Platforms must be fully planked or decked, with no gaps wider than 1 inch, and be at least 18 inches wide where possible.
- Guardrails and toe boards are required on open sides, and the top rail is 38 to 45 inches high. Use a personal fall arrest system where guardrails are not enough.
- Provide a safe way up, such as a ladder or stair tower. Never climb cross braces.
- Inspect the scaffold before every shift and after anything that could affect its structure. Do not use a scaffold that is damaged.
- Keep power lines at a safe distance, and do not work on a scaffold in storms or high winds.
- Do not overload it, and do not let debris build up on the platforms.
- Train every worker who uses a scaffold to recognise its hazards.
Page 3 of 3 in this chapter · page 27 of 29 in the book
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