For rope lengths over 915 meters, the maximum safe working load shall not exceed what fraction of the breaking load?

• A. 1/4
• B. 1/5
• C. 1/3
• D. 1/6

Answer: (A)

When a rope runs a very long distance, the tension it experiences can spike due to dynamic effects, acceleration, and wear in drums and guides. To keep operations safe under those tougher conditions, the allowable working load is reduced to a smaller fraction of the rope’s breaking load. For rope lengths over 915 meters, the standard sets the maximum safe working load at one quarter of the breaking load. So, if the rope’s breaking load is 100 kN, you should limit service loads to 25 kN. The other fractions either allow more load than this long-rope rule permits or are more restrictive than required, so they don’t match the specified limit for this length.