CHST Crane and Rigging Safety 5 — Questions and Answers
Question 1: What is the purpose of a tag line during a crane lift?
- To signal the operator when to stop hoisting
- To control load swing and rotation without personnel being in the load path (Correct answer)
- To anchor the load to the ground until lifting begins
- To connect the crane's block to the rigging hardware
Correct answer: To control load swing and rotation without personnel being in the load path
Tag lines allow ground workers to guide and stabilize a suspended load while keeping them out of the hazardous zone directly under or near the load.
Question 2: Which rigging configuration reduces a sling's rated capacity the most?
- Vertical hitch
- Basket hitch at 60-degree included angle
- Choker hitch
- Basket hitch at 30-degree included angle (Correct answer)
Correct answer: Basket hitch at 30-degree included angle
As the sling angle decreases from vertical, horizontal tension increases; a very narrow basket hitch (30° included angle) produces the greatest reduction in effective capacity.
Question 3: Under OSHA 29 CFR 1926.1427, who is required to be a Qualified Rigger?
- Anyone who enters the crane exclusion zone
- Personnel who attach or detach rigging to a load (Correct answer)
- The appointed signal person for the lift
- The competent person performing the pre-shift inspection
Correct answer: Personnel who attach or detach rigging to a load
OSHA 1926.1427 requires that only qualified riggers attach or detach rigging from a load, ensuring personnel have the knowledge and experience to rig safely.
Question 4: What does a crane's 'derating' mean in the context of crane operations?
- Lowering the boom speed during a pick
- Reducing the rated capacity due to configuration, attachment, or site conditions (Correct answer)
- Increasing the counterweight to allow heavier lifts
- Removing the anti-two-block device for special lifts
Correct answer: Reducing the rated capacity due to configuration, attachment, or site conditions
Derating means the crane's capacity is officially reduced below the manufacturer's chart value to account for conditions such as soft ground, outrigger restrictions, or non-standard configuration.
Question 5: A crane operator receives conflicting hand signals from two workers during a lift. What should the operator do?
- Follow the signal from the worker closest to the load
- Stop the crane and do not move until one designated signal person is identified (Correct answer)
- Follow the signal from the more experienced worker
- Continue the lift at reduced speed until signals are clarified
Correct answer: Stop the crane and do not move until one designated signal person is identified
OSHA requires only one designated signal person per lift; receiving conflicting signals is a stop-work condition until a single signal person is confirmed.
Question 6: When rigging a load with a multiple-leg bridle, the weight distribution is calculated assuming how many legs bear the load?
- All legs equally
- Three legs, regardless of actual number
- Two legs, because load distribution is uneven in three- and four-leg slings (Correct answer)
- Only the two legs with the greatest tension
Correct answer: Two legs, because load distribution is uneven in three- and four-leg slings
Standard rigging practice assumes only two legs of a multi-leg bridle are loaded at any time because slight differences in leg length or load geometry prevent equal sharing among three or four legs.
Question 7: What is the maximum allowable body wear (reduction in original rope diameter) that causes a wire rope to be removed from service under ASME B30.2?
- 5% reduction
- One-third (33%) reduction (Correct answer)
- 10% reduction
- One-sixth (17%) reduction
Correct answer: One-third (33%) reduction
ASME B30.2 specifies that wire rope must be removed from service when the actual diameter is reduced by one-third or more from its nominal diameter due to wear.
CHST Crane and Rigging Safety 5
What is the purpose of a tag line during a crane lift?