OSHA 10-Hour Construction ReviewStairways and LaddersMedium

A scaffold builder needs to access a work platform located 15 feet (4.57 meters) above the ground. The crew has a straight ladder available. What is the minimum length this straight ladder must be to meet OSHA requirements for accessing the platform?

  1. A18 feet (5.49 meters)
  2. B19 feet (5.79 meters)
  3. C15 feet (4.57 meters)
  4. D16 feet (4.88 meters)
Show answer & explanation

Correct answer: B. 19 feet (5.79 meters)

OSHA requires that the side rails of a portable ladder used to access an upper landing surface must extend at least 3 feet (91 cm) above that surface. Therefore, for a 15-foot platform, the ladder must be at least 15 feet + 3 feet = 18 feet long. However, ladders are sold in specific lengths, and the next standard length above 18 feet would be 19 feet, assuming typical increments.

Why the other options are wrong

  • A. This length meets the minimum 18-foot requirement (15 + 3), but if standard increments are considered, 19ft is a common length.
  • C. This length would not allow the ladder to extend above the platform as required by OSHA.
  • D. This length is still too short to meet the 3-foot extension rule.

Ladder Length Calculation

Required ladder length = height to landing + 3 feet extension.

  • 3-foot extension is for a safe handhold.
  • Always round up to the next available standard ladder length.
  • Applies to portable ladders accessing elevated surfaces.

Memory trick: Height plus three, for safety, you see!

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