National Commission for the Certification of Crane Operators (NCCCO) Mobile Crane Practice Exam

What is the design factor for rotation resistant rope used as a hoist line?

1. 3:1

2. 4:1

3. 5:1

4. 6:1

The correct answer is: 5:1

The design factor for rotation-resistant rope used as a hoist line is indeed 5:1. This means that the rope is designed to support loads up to five times its rated capacity without failing. This higher design factor is critical in ensuring safety, particularly when lifting loads that can create additional rotational torque on the hoist line. Rotation-resistant ropes are designed to minimize the risk of torsion and to maintain the proper orientation of the load being lifted. The 5:1 factor reflects the extra safety margin needed due to the dynamic forces and potential hazards associated with lifting, especially in environments where load stability can be compromised. Using a design factor of 5:1 ensures that operators have a considerable buffer against sudden shocks, dynamic loading, and other unpredictable factors that could lead to rope failure during operations. This is particularly important in crane operations where the integrity of the lifting system is paramount to prevent accidents and ensure the safety of personnel and equipment.