NCCCO Wire Rope Inspection and Replacement Criteria 2 — Questions and Answers
Question 1: How many visible broken wires in one rope lay length require wire rope replacement on a running rope?
- 1 broken wire
- 3 broken wires
- 6 or more broken wires in one lay, or 3 in one strand (Correct answer)
- Any broken wire requires immediate replacement
Correct answer: 6 or more broken wires in one lay, or 3 in one strand
ASME B30.5 requires replacement when there are 6 randomly distributed broken wires in one lay length, or 3 broken wires in one strand. Different standards may apply to standing ropes.
Question 2: What is 'rope lay length' and how is it measured?
- The total length of the rope
- The distance along the rope for one complete helical wrap of one strand around the core — typically measured by marking a strand and finding where it returns to the same position (Correct answer)
- The distance from drum to sheave
- The length of rope on the drum
Correct answer: The distance along the rope for one complete helical wrap of one strand around the core — typically measured by marking a strand and finding where it returns to the same position
One rope lay is the distance along the rope in which a single strand makes one complete revolution around the core. This is the inspection unit for counting broken wires.
Question 3: A wire rope shows a diameter reduction of 5% from its original diameter. What does this indicate?
- Normal stretching
- Significant internal wear, corrosion, or core degradation requiring investigation and likely replacement (Correct answer)
- The rope has been lubricated recently
- The rope is getting stronger
Correct answer: Significant internal wear, corrosion, or core degradation requiring investigation and likely replacement
Diameter reduction indicates internal problems: broken core wires, internal corrosion, or compression wear. Even without visible external damage, diameter reduction signals serious degradation.
Question 4: What does heat damage look like on wire rope and why is it serious?
- Rope turns red temporarily
- Discoloration (blue, brown, or black), distortion, or annealing of wires that permanently reduces strength (Correct answer)
- Heat damage makes rope more flexible
- Heat treatment improves rope strength
Correct answer: Discoloration (blue, brown, or black), distortion, or annealing of wires that permanently reduces strength
Heat from friction, welding, or fire anneals the wire, reducing its tensile strength. Even without visible damage, heat-affected rope may have lost significant load-bearing capacity.
Question 5: How should wire rope be stored when not in use?
- Coiled loosely on the ground
- On a reel in a dry, ventilated area, protected from moisture, chemicals, and physical damage (Correct answer)
- Hanging from a hook to keep it straight
- Submerged in oil for preservation
Correct answer: On a reel in a dry, ventilated area, protected from moisture, chemicals, and physical damage
Proper storage prevents corrosion and physical damage: keep on a reel (prevents kinks), in a dry location (prevents corrosion), with ventilation (prevents moisture buildup), and protected from chemicals.
Question 6: What must be done before a new wire rope is put into service?
- Nothing — new rope is ready to use
- Break-in the rope with several light load cycles, inspect for damage from shipping, and verify the rope specification matches the crane requirements (Correct answer)
- Just uncoil it and start lifting
- Soak it in oil for 24 hours
Correct answer: Break-in the rope with several light load cycles, inspect for damage from shipping, and verify the rope specification matches the crane requirements
New rope must be inspected for shipping damage, verified against specifications, and 'broken in' with light load cycles. This seats the strands and identifies any manufacturing defects.
NCCCO Wire Rope Inspection and Replacement Criteria 2
How many visible broken wires in one rope lay length require wire rope replacement on a running rope?