Pipefitter Rigging, Hangers, and Supports 3 — Questions and Answers
Question 1: When inspecting a wire rope sling before a lift, which defect requires the sling to be immediately removed from service?
- Minor surface oxidation
- Six randomly distributed broken wires in one rope lay (Correct answer)
- Slight kinking at the end fitting
- Light grease accumulation on strands
Correct answer: Six randomly distributed broken wires in one rope lay
Six or more randomly distributed broken wires in one rope lay is a disqualifying defect per ASME B30.9.
Question 2: A spring hanger is used instead of a rigid support when:
- The pipe operates at ambient temperature
- Thermal expansion causes the pipe to move vertically during operation (Correct answer)
- The pipe carries a low-pressure fluid
- The support point is near a fixed anchor
Correct answer: Thermal expansion causes the pipe to move vertically during operation
Spring hangers accommodate vertical pipe movement caused by thermal expansion while maintaining a controlled load.
Question 3: What is the purpose of a pipe anchor (fixed point) in a piping system?
- To allow free axial movement of the pipe
- To prevent all movement and absorb forces at a specific location (Correct answer)
- To guide pipe movement in one direction only
- To reduce vibration by adding damping mass
Correct answer: To prevent all movement and absorb forces at a specific location
An anchor restrains the pipe against all movement and absorbs thermal, pressure, and dynamic forces at that point.
Question 4: Which rigging configuration provides the greatest mechanical advantage when using a block and tackle system?
- Single fixed block
- Two fixed blocks with one rope part
- Four-part line (double block and tackle) (Correct answer)
- Single movable block with two rope parts
Correct answer: Four-part line (double block and tackle)
A four-part line doubles the mechanical advantage compared to a two-part line, allowing a lighter applied force to lift heavier loads.
Question 5: What does the term 'SWL' stamped on rigging hardware indicate?
- Standard Wire Length
- Safe Working Load (Correct answer)
- Steel Wire Limit
- Structural Weight Limit
Correct answer: Safe Working Load
SWL (Safe Working Load) is the maximum load a piece of rigging hardware is rated to carry under normal working conditions.
Question 6: A constant-effort (constant-support) hanger maintains a consistent load on the pipe by using:
- A rigid rod with no adjustment
- A coil spring with a variable rate
- A counterbalance mechanism that keeps force constant throughout travel (Correct answer)
- A hydraulic cylinder with fixed pressure
Correct answer: A counterbalance mechanism that keeps force constant throughout travel
Constant-effort hangers use a cam-and-spring or counterweight mechanism to maintain a nearly constant supporting force regardless of pipe position.
Question 7: When a load is suspended from two sling legs at a 60° angle from horizontal, the tension in each leg compared to a vertical single-leg lift of the same load is:
- Less than the load weight
- Equal to the load weight
- Greater than the load weight (Correct answer)
- Twice the load weight
Correct answer: Greater than the load weight
As the sling angle decreases below 90° from horizontal, the tension in each leg increases beyond the simple load weight due to the horizontal force component.
Pipefitter Rigging, Hangers, and Supports 3
When inspecting a wire rope sling before a lift, which defect requires the sling to be immediately removed from service?