NCCCO Sling Types and Load Distribution 3 — Questions and Answers
Question 1: When using a two-leg bridle sling at a 60-degree angle from horizontal, the tension in each leg compared to a vertical hitch is approximately:
- Equal to the vertical load
- 1.15 times the load per leg (Correct answer)
- 2 times the load per leg
- 0.5 times the load per leg
Correct answer: 1.15 times the load per leg
At 60 degrees from horizontal, the tension factor is approximately 1.15, so each leg carries slightly more than the load divided by two.
Question 2: A wire rope sling with a kinked or birdcaged section should be:
- Used only for light loads
- Straightened before use with a hammer
- Removed from service immediately (Correct answer)
- Used in a basket hitch only
Correct answer: Removed from service immediately
Kinked or birdcaged wire rope slings are permanently damaged and must be removed from service because their rated capacity is significantly compromised.
Question 3: Which sling type is most susceptible to damage from ultraviolet (UV) light exposure?
- Wire rope slings
- Chain slings
- Synthetic web slings (Correct answer)
- Alloy steel chain
Correct answer: Synthetic web slings
Synthetic web slings made from nylon or polyester degrade when exposed to prolonged UV light, weakening the fibers and reducing rated capacity.
Question 4: When a load is lifted with an unbalanced center of gravity using a single vertical hitch, the risk is:
- Sling overheating
- Load spinning freely with no hazard
- Load tipping or swinging uncontrollably (Correct answer)
- Reduced sling stretch
Correct answer: Load tipping or swinging uncontrollably
A single vertical hitch on an off-center load will cause the load to tip or swing because it cannot resist rotational forces.
Question 5: The D/d ratio for wire rope slings refers to:
- Diameter of the load divided by sling diameter
- Bend radius of the fitting divided by wire rope diameter (Correct answer)
- Load weight divided by sling rated capacity
- Depth of the hook throat divided by wire diameter
Correct answer: Bend radius of the fitting divided by wire rope diameter
The D/d ratio is the diameter of curvature (bend) divided by the wire rope diameter; lower ratios cause efficiency loss and must meet minimum requirements.
Question 6: A choker hitch reduces a wire rope sling's rated capacity by approximately how much compared to a vertical hitch?
- 10%
- 25% (Correct answer)
- 50%
- 75%
Correct answer: 25%
A choker hitch typically reduces capacity to 75–80% of the vertical hitch rating, roughly a 20–25% reduction, due to the bend stress at the choke point.
Question 7: What is the purpose of a spreader bar when used with multiple slings?
- To increase the sling angle beyond 60 degrees
- To keep slings vertical and reduce compressive forces on the load (Correct answer)
- To eliminate the need for rated capacity tags
- To convert a wire rope sling to a synthetic sling
Correct answer: To keep slings vertical and reduce compressive forces on the load
A spreader bar maintains the slings in a more vertical position, reducing sling tension and preventing inward compressive forces that could damage the load.
NCCCO Sling Types and Load Distribution 3
When using a two-leg bridle sling at a 60-degree angle from horizontal, the tension in each leg compared to a vertical hitch is approximately: