What is the minimum distance that guardrails must extend beyond the last plank on a scaffold platform?
Correct Answer
D) 6 inches
OSHA 1926.451(e)(3) requires guardrails to extend at least 6 inches beyond the end of the scaffold platform to provide adequate protection.
Why This Is the Correct Answer
OSHA 29 CFR 1926.451(e)(3) requires that guardrails extend at least 6 inches beyond the end of the scaffold platform. This overhang provides a protective barrier preventing workers from stepping off the unguarded end of the platform while still allowing them to work near the edge.
Why the Other Options Are Wrong
Option A: 12 inches
12 inches is double the required minimum and is not cited in OSHA 1926.451. This value may be confused with other scaffold dimensions, such as the maximum gap between planks (which must be 1 inch or less) or toe board heights. The 12-inch figure is a plausible-sounding distractor that exceeds the actual requirement.
Option B: 18 inches
18 inches is not the OSHA standard for guardrail extension beyond scaffold planks. This number appears in other OSHA contexts (e.g., the minimum width of stairways in some configurations), making it a tempting but incorrect choice for candidates who recall 18 inches from a different scaffold or safety rule.
Option C: 9.5 inches
9.5 inches is not referenced in OSHA 1926.451 for this requirement. It is a specific distractor likely included because it sounds like a precise engineering measurement, which lends it false credibility. No standard guardrail extension for scaffold platforms uses this dimension.
Memory Technique
Six inches = half a foot. Imagine placing a standard ruler (12 inches) and cutting it in half — that 6-inch half sticks out past the last plank. Or simply think: '6 inches beyond, not a foot, not a foot and a half — just half a foot.'
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