Pipefitter Rigging, Hangers, and Supports 5 — Questions and Answers
Question 1: Pipe shoes (pipe saddles) are used on insulated lines primarily to:
- Increase friction between pipe and support
- Transfer load to the support steel without compressing or damaging the insulation (Correct answer)
- Attach the pipe permanently to structural steel
- Reduce water hammer effects in the line
Correct answer: Transfer load to the support steel without compressing or damaging the insulation
Pipe shoes extend below the insulation to rest on the support, keeping the insulation intact and continuous.
Question 2: The rated capacity of a synthetic web sling is reduced most significantly when the sling is used in a:
- Vertical hitch configuration
- Basket hitch at 90° leg angle
- Choker hitch (Correct answer)
- Double-wrapped basket hitch
Correct answer: Choker hitch
A choker hitch reduces a synthetic sling's rated capacity to approximately 75–80% of its vertical hitch rating due to the choke point stress.
Question 3: When multiple pipe hangers are installed on a beam, the maximum spacing between supports is determined primarily by:
- The pipe color code designation
- Pipe material, diameter, operating temperature, and fluid weight (Correct answer)
- The number of workers available for installation
- The distance between adjacent structural bays only
Correct answer: Pipe material, diameter, operating temperature, and fluid weight
Support spacing is calculated from allowable pipe sag (deflection) based on pipe size, wall thickness, material, and the combined weight of pipe, fluid, and insulation.
Question 4: A rigger observes that a load is drifting to one side during a crane lift. The correct action is to:
- Apply a tag line to redirect the load
- Increase crane boom angle to rebalance
- Lower the load and rerig it correctly (Correct answer)
- Adjust the hoist speed to compensate
Correct answer: Lower the load and rerig it correctly
A load drifting sideways indicates the rigging attachment point is not directly above the load's center of gravity; the correct response is to lower and rerig.
Question 5: Variable spring hangers must be set to their 'cold' (installation) position before hydrostatic testing because:
- Hot position locks the spring permanently
- Water weight during testing is much greater than operating fluid weight (Correct answer)
- The spring rate changes after the first thermal cycle
- OSHA requires it for all pressure tests
Correct answer: Water weight during testing is much greater than operating fluid weight
Water is significantly heavier than most process fluids, so springs must be set for the cold/empty load to avoid overloading during the water-filled test.
Question 6: Which factor most directly determines the required hanger rod diameter for a given pipe support?
- The diameter of the pipe being supported
- The total load (pipe, fluid, insulation) carried by the rod (Correct answer)
- The height from the support steel to the pipe centerline
- The ambient temperature at the support location
Correct answer: The total load (pipe, fluid, insulation) carried by the rod
Rod diameter is selected based on the total tensile load the rod must carry, which includes pipe weight, fluid weight, insulation weight, and any dynamic loads.
Question 7: Before a rigger uses a wire rope clip (U-bolt clip) to form an eye termination, the correct orientation requires:
- The U-bolt saddle on the live (load) side of the rope
- The U-bolt saddle on the dead (short) end of the rope (Correct answer)
- Both clips facing the same direction regardless of live/dead side
- The clip installed without lubricant to increase friction
Correct answer: The U-bolt saddle on the dead (short) end of the rope
The rule 'never saddle a dead horse' means the U-bolt (saddle) must bear on the dead (short) end, not the live load-bearing rope.
Pipefitter Rigging, Hangers, and Supports 5
Pipe shoes (pipe saddles) are used on insulated lines primarily to: