NCCCO Rigging Techniques & Equipment Inspection 2 — Questions and Answers
Question 1: What is the rated capacity of a sling determined by?
- Its color
- The sling type, size, configuration (hitch type), and angle of use (Correct answer)
- The length of the sling only
- How new the sling looks
Correct answer: The sling type, size, configuration (hitch type), and angle of use
Sling capacity depends on the type (wire rope, chain, synthetic), diameter/grade, hitch configuration (vertical, choker, basket), and the angle relative to vertical. Capacity tags must be attached.
Question 2: How does sling angle affect lifting capacity?
- Angle has no effect on capacity
- As the sling angle decreases from vertical, the tension on each sling leg increases, reducing the effective capacity (Correct answer)
- Wider angles always increase capacity
- Only matters for chain slings
Correct answer: As the sling angle decreases from vertical, the tension on each sling leg increases, reducing the effective capacity
When slings are spread at an angle, each leg must support more than its share of the vertical load due to the horizontal force component. At 30° from horizontal, each leg experiences twice the vertical load.
Question 3: What must be checked during a pre-use inspection of wire rope slings?
- Only the end fittings
- Broken wires, kinks, crushing, corrosion, heat damage, end fitting condition, and the capacity tag (Correct answer)
- Just the overall length
- Only visible rust
Correct answer: Broken wires, kinks, crushing, corrosion, heat damage, end fitting condition, and the capacity tag
Pre-use inspection covers: broken wires (count per rope lay), kinks, crushing, bird-caging, corrosion, heat damage (discoloration), end fitting integrity, and a legible capacity tag.
Question 4: What is a 'choker hitch' and when is it used?
- A decorative knot
- A sling configuration where the sling wraps around the load and the eye passes through the other eye, cinching tight on the load (Correct answer)
- A method of connecting two cranes
- A safety harness for the operator
Correct answer: A sling configuration where the sling wraps around the load and the eye passes through the other eye, cinching tight on the load
A choker hitch wraps the sling around the load and cinches tight, gripping the load through friction. It's used when loads need to be gripped tightly, but it reduces sling capacity to approximately 75% of vertical rating.
Question 5: Shackles used in rigging must be inspected for what conditions?
- Only color fading
- Deformation, wear, corrosion, cracks, proper pin installation, and correct working load limit for the application (Correct answer)
- Just that the pin is present
- Only weight markings
Correct answer: Deformation, wear, corrosion, cracks, proper pin installation, and correct working load limit for the application
Shackle inspection includes checking for deformation (bent or stretched), wear at contact points, corrosion, cracks, proper pin installation (correct pin type, fully threaded), and appropriate WLL rating.
Question 6: What is the purpose of a 'tag line' in rigging?
- To identify the load with a tag
- A rope attached to the load to control rotation and swing during lifting without workers being near the suspended load (Correct answer)
- To tag the crane for identification
- To line up the load with the boom
Correct answer: A rope attached to the load to control rotation and swing during lifting without workers being near the suspended load
Tag lines allow ground workers to guide and control load rotation and swing from a safe distance, without standing under or near the suspended load. They're essential for precise load placement.
NCCCO Rigging Techniques & Equipment Inspection 2
What is the rated capacity of a sling determined by?