Pipefitter Rigging and Hoisting Operations 4 — Questions and Answers
Question 1: What is the minimum safety factor (design factor) required for wire rope slings used in rigging operations per ASME B30.9?
- 3:1
- 5:1 (Correct answer)
- 7:1
- 10:1
Correct answer: 5:1
ASME B30.9 requires a minimum design factor of 5:1 for wire rope slings used in rigging.
Question 2: When a load is suspended from two sling legs with a 120-degree included angle between them, each leg carries approximately what percentage of the total load?
- 50%
- 75%
- 100% (Correct answer)
- 115%
Correct answer: 100%
At a 120-degree included angle, each sling leg carries 100% of the total load due to the increased tension from the wide angle.
Question 3: Which type of rigging hardware is used to change the direction of a wire rope without creating a fixed termination?
- Shackle
- Snatch block (Correct answer)
- Swivel hoist ring
- Turnbuckle
Correct answer: Snatch block
A snatch block (also called a redirect block) allows wire rope to change direction while the rope remains free to move through it.
Question 4: What is the correct procedure when a tag line is used during a crane lift?
- Wrap it around your hand for a better grip
- Keep it taut at all times regardless of load position
- Use it to guide the load without pulling the hook off center (Correct answer)
- Attach it to the crane hook for better control
Correct answer: Use it to guide the load without pulling the hook off center
Tag lines are used to guide and control load rotation without pulling the crane hook off-center, which could cause side loading.
Question 5: A pipefitter is rigging a horizontal pipe using a double-wrap choker hitch. Compared to a single choker, the double-wrap choker increases the rated capacity by approximately:
- 10%
- 25% (Correct answer)
- 50%
- 100%
Correct answer: 25%
A double-wrap choker hitch increases the rated capacity by approximately 25% compared to a single choker hitch.
Question 6: What is the maximum allowable D/d ratio recommended for a wire rope running over a sheave to minimize rope wear?
- 5:1
- 10:1
- 20:1 (Correct answer)
- 34:1
Correct answer: 20:1
A minimum D/d ratio of 20:1 (sheave diameter to rope diameter) is generally recommended to minimize wire rope fatigue and wear.
Question 7: Which condition requires immediate removal of a wire rope sling from service?
- Any surface rust visible on individual wires
- Six randomly distributed broken wires in one rope lay (Correct answer)
- Slight kinking that straightens when load is removed
- Minor discoloration from exposure to sunlight
Correct answer: Six randomly distributed broken wires in one rope lay
Per ASME B30.9, six randomly distributed broken wires in one rope lay is a criterion for removing a wire rope sling from service.
Pipefitter Rigging and Hoisting Operations 4
What is the minimum safety factor (design factor) required for wire rope slings used in rigging operations per ASME B30.9?