OSHA 10-Hour Construction ReviewScaffoldsMedium
A worker is setting up a supported scaffold with a height-to-base ratio that exceeds 4:1. What additional measure is specifically required by OSHA to ensure the stability of this scaffold?
- AErect a separate, independent support structure.
- BTie, guy, or brace the scaffold to prevent tipping.
- CReduce the total number of workers on the platform.
- DInstall a safety net below the scaffold.
Show answer & explanationAnswer & explanation
Correct answer: B. Tie, guy, or brace the scaffold to prevent tipping.
OSHA regulation 1926.451(c)(1)(i) states that supported scaffolds with a height-to-base width ratio of more than four to one (4:1) must be restrained from tipping by guying, tying, bracing, or an equivalent means.
Why the other options are wrong
- A. Erecting a separate support structure is not the standard or required method for stabilizing a scaffold exceeding the 4:1 ratio.
- C. Reducing the number of workers might reduce the load but does not inherently stabilize a scaffold prone to tipping due to an unfavorable height-to-base ratio.
- D. A safety net is fall protection, not a primary measure for scaffold stability against tipping.
Scaffold Height-to-Base Ratio
Supported scaffolds must have a stable height-to-base ratio, or they require additional stabilization measures.
- Maximum unsupported height-to-base ratio: 4:1.
- If ratio exceeds 4:1, scaffold must be tied, guyed, or braced.
- This prevents tipping and ensures overall scaffold stability.
- A competent person must determine the adequacy of these measures.
Memory trick: Four-to-One, Tie it Done.