The correct answer is based on the guidelines set forth in the ASME B30.5 Mobile Crane Standard regarding the integrity of rotation-resistant rope used in crane applications. The standard specifies that if two broken wires are found within six rope diameters, the rope should be replaced. This criterion is established to ensure the safety and reliability of the lifting equipment.
Rotation-resistant ropes are designed to reduce the twisting that may occur during lifting operations. The presence of broken wires indicates potential damage or fatigue in the rope, which can compromise its performance and safety margins. The metric of measuring broken wires within six diameters helps evaluate the condition of the rope over a reasonable length of its structure, encompassing potential areas of weakness.
Other options do not align with the established guidelines. For instance, one broken wire in one foot could be more acceptable under certain conditions, but it does not trigger the proactive replacement measure that the standard mandates. Similarly, three broken wires in one lay or four broken wires in any strand might not accurately reflect the overall structural integrity as outlined by ASME B30.5. Therefore, the necessity for two broken wires within six rope diameters serves as a critical threshold for maintenance and safety compliance in crane operations.