Pipefitter Pipe Fabrication Methods 3 — Questions and Answers
Question 1: When fabricating a 90-degree elbow using the miter cut method on 6-inch pipe, how many cuts are required to produce a two-piece miter?
- 1 cut
- 2 cuts (Correct answer)
- 3 cuts
- 4 cuts
Correct answer: 2 cuts
A two-piece miter elbow requires 2 cuts, each at 45 degrees, which when welded together form a 90-degree change in direction.
Question 2: Which fabrication technique is used to create a branch connection on a pipe run without cutting out a full section of pipe?
- Butt weld fitting
- Saddle or Weldolet fitting (Correct answer)
- Socket weld coupling
- Lap joint flange
Correct answer: Saddle or Weldolet fitting
A saddle or Weldolet fitting is welded directly onto the pipe run and requires only a hole to be cut, not removal of a full pipe section.
Question 3: What is the purpose of a 'rolling offset' in pipe fabrication?
- To connect pipes of different wall thickness
- To change pipe direction in two planes simultaneously (Correct answer)
- To increase pipe flow velocity
- To reduce thermal expansion stress
Correct answer: To change pipe direction in two planes simultaneously
A rolling offset changes the direction of a pipe run in both the horizontal and vertical planes at the same time.
Question 4: In pipe fabrication, what does the term 'takeout' refer to?
- The length of pipe removed after cutting
- The amount subtracted from the overall measurement to account for a fitting's end-to-center dimension (Correct answer)
- The distance a pipe extends past a flange face
- The gap left for weld penetration
Correct answer: The amount subtracted from the overall measurement to account for a fitting's end-to-center dimension
Takeout is the end-to-center dimension of a fitting that must be subtracted from the overall run length to determine the actual cut length of pipe.
Question 5: Which method is commonly used to fabricate large-diameter pipe spools in a shop environment to ensure dimensional accuracy?
- Field fit-up with tack welds
- Use of fabrication fixtures and rolling stands (Correct answer)
- Hand-held magnetic clamps only
- Threading and coupling assembly
Correct answer: Use of fabrication fixtures and rolling stands
Fabrication fixtures and rolling stands keep large-diameter spools aligned and supported during welding, ensuring dimensional accuracy.
Question 6: What is the correct sequence when laying out a pipe spool for fabrication?
- Cut, mark, fit-up, weld
- Mark, cut, fit-up, weld (Correct answer)
- Fit-up, mark, cut, weld
- Weld, cut, mark, fit-up
Correct answer: Mark, cut, fit-up, weld
The correct sequence is mark (layout), cut to length, fit-up components, then weld — ensuring accuracy before committing to cuts.
Question 7: When fabricating a concentric reducer using plate, the transition cone is developed using which geometric method?
- Triangulation
- Radial line development (Correct answer)
- Parallel line development
- Rectangular coordinate layout
Correct answer: Radial line development
Concentric reducer cones are developed using radial line development, where lines radiate from a common apex point of the cone.
Pipefitter Pipe Fabrication Methods 3
When fabricating a 90-degree elbow using the miter cut method on 6-inch pipe, how many cuts are required to produce a two-piece miter?