CSLB C-33 Painting & DecoratingSafetyMedium
A painting crew is setting up a mobile scaffold (rolling scaffold) for interior painting tasks. According to OSHA, what is the maximum height-to-base width ratio allowed for a mobile scaffold unless it is secured against tipping?
- A5 to 1
- B4 to 1
- C2 to 1
- D3 to 1
Show answer & explanationAnswer & explanation
Correct answer: B. 4 to 1
OSHA 1926.452(w)(6) states that the height of a mobile scaffold must not exceed four times the minimum base dimension unless it is guyed, tied, or braced to prevent tipping.
Why the other options are wrong
- A. 5 to 1 exceeds the OSHA maximum ratio for unsecured mobile scaffolds and would require bracing or tying off.
- C. 2 to 1 is a common safe ratio for some other structures but not the OSHA limit for mobile scaffolds.
- D. 3 to 1 is a more conservative ratio, but not the specific OSHA maximum without securing.
Mobile Scaffold Height-to-Base Ratio
OSHA specifies that the height of a mobile scaffold must not exceed four times its minimum base dimension unless it is secured to prevent tipping.
- Minimum base dimension is the narrowest side of the scaffold base.
- Securing methods include guying, tying, or bracing.
- This ratio is critical for scaffold stability and preventing overturns.
Memory trick: Four-to-One: Firm Footing, Fewer Falls.