OSHA 10-Hour Construction ReviewScaffoldsHard
A worker is installing scaffold planks on a supported scaffold. OSHA requires that scaffold planks extending beyond their end supports, without being cleated or otherwise restrained, must not extend more than what maximum distance?
- A6 inches
- B18 inches
- C9 inches
- D12 inches
Show answer & explanationAnswer & explanation
Correct answer: D. 12 inches
OSHA regulation 1926.451(b)(10) states that scaffold planks (or platforms) must extend over their end supports by at least 6 inches (15 cm), but not more than 12 inches (30 cm), unless they are cleated or otherwise restrained by hooks or equivalent means.
Why the other options are wrong
- A. 6 inches is the minimum required overlap, not the maximum extension without restraint.
- B. 18 inches exceeds the maximum allowable overhang and would create a tipping hazard.
- C. 9 inches is within the acceptable range but not the specified maximum.
Scaffold Plank Overhang
The distance a scaffold plank can extend beyond its support without additional securing measures is strictly regulated to prevent tipping.
- Minimum overlap: 6 inches.
- Maximum overhang without restraint: 12 inches (1 foot).
- If exceeding 12 inches, planks must be cleated, hooked, or otherwise restrained.
- Prevents planks from tipping when weight is applied to the unsupported end.
Memory trick: Six to Twelve, Don't Over-Shelve.