What is the design factor for rotation-resistant load hoist wire rope according to ASME B30.3?

The design factor for rotation-resistant load hoist wire rope according to ASME B30.3 is established at 5.0 to 1, meaning that the breaking strength of the wire rope needs to be at least five times greater than the maximum load imposed on it during use. This design factor takes into account the unique stresses and potential for rotation that these types of ropes endure, especially in applications where loads can create torque or twisting moments.

Using a design factor of 5.0 to 1 ensures an adequate safety margin, accommodating for variations in load conditions, wear and tear, and unforeseen circumstances that could affect the rope's integrity. This level of design factor is particularly important in ensuring the safety of operations involving tower cranes, as the risks associated with load failure can have serious consequences.

The other options provided (3.0 to 1, 4.0 to 1, and 6.0 to 1) do not align with the requirements outlined in the ASME B30.3 standards for rotation-resistant wire rope, which specifically emphasizes a factor of 5.0 to 1 as necessary for safety in crane operations.