NCCCO Rigging Fundamentals and Hardware 4 — Questions and Answers
Question 1: When a sling is used in a choker hitch, the rated capacity compared to a straight vertical hitch is:
- Increased by 25%
- Reduced to approximately 75% (Correct answer)
- Unchanged
- Reduced to 50%
Correct answer: Reduced to approximately 75%
A choker hitch reduces sling capacity to approximately 75% of the vertical hitch rating due to the bend angle created at the choke point.
Question 2: What is the primary purpose of a shackle's safety pin or bolt?
- To increase the shackle's working load limit
- To prevent the pin from unscrewing under load (Correct answer)
- To identify the shackle's manufacturer
- To align the load evenly across the bow
Correct answer: To prevent the pin from unscrewing under load
The safety pin or cotter pin prevents the shackle pin from unscrewing due to vibration or load rotation during a lift.
Question 3: A spreader beam is used in a rigging configuration primarily to:
- Increase the total weight capacity of the crane
- Keep sling legs vertical and prevent inward compression on the load (Correct answer)
- Reduce the number of slings needed for a lift
- Increase the hook height above the load
Correct answer: Keep sling legs vertical and prevent inward compression on the load
Spreader beams maintain sling legs in a vertical or near-vertical position, preventing compressive forces from being applied to fragile or wide loads.
Question 4: Which of the following conditions requires immediate removal of a wire rope sling from service?
- Minor surface rust on outer wires
- Six randomly distributed broken wires in one rope lay (Correct answer)
- Slight stiffness from cold temperatures
- A small amount of lubricant residue on the surface
Correct answer: Six randomly distributed broken wires in one rope lay
ASME B30.9 requires wire rope slings to be removed from service if six or more randomly distributed broken wires are found in one rope lay.
Question 5: When two slings are used in a basket hitch with a 60-degree angle from horizontal, the tension in each sling leg compared to the load weight is:
- Equal to the load weight
- Less than half the load weight
- Greater than half the load weight (Correct answer)
- Equal to half the load weight
Correct answer: Greater than half the load weight
At 60 degrees from horizontal, the sling tension factor exceeds 0.5, meaning each leg carries more than half the total load weight.
Question 6: What does the term 'proof load' mean for a rigging component?
- The maximum load the component can carry before permanent deformation
- A test load applied to verify the component's integrity before use (Correct answer)
- The load applied during normal working operations
- The load that will cause immediate failure of the component
Correct answer: A test load applied to verify the component's integrity before use
Proof load is a test load—typically twice the working load limit—applied to a rigging component to verify it can safely handle its rated capacity.
Question 7: A synthetic web sling is discovered to have a cut that penetrates through to the load-bearing yarns. The correct action is to:
- Use the sling for lighter loads only
- Tag the sling and set it aside for inspection by a supervisor
- Immediately remove the sling from service and destroy it (Correct answer)
- Repair the sling with heavy-duty tape before next use
Correct answer: Immediately remove the sling from service and destroy it
Any cut penetrating the load-bearing yarns of a synthetic web sling requires immediate removal from service and destruction per ASME B30.9.
NCCCO Rigging Fundamentals and Hardware 4
When a sling is used in a choker hitch, the rated capacity compared to a straight vertical hitch is: