200+ Piping Interview Questions and Answers
1. What is the pipe size range for shop-fabricated pipe spools, according to Fluor Daniel standards?
3" and greater diameters 2.1/2" and larger>
2. What is the pipe size range for field-fabricated pipe spools, according to the Fluor Daniel standard?
2" and smaller diameters
3. Define "field assembly" in terms of piping.
Ans: Off-the-shelf components that go into a piping assembly and don't need to be cut or welded.
If no fabrication in the field is necessary>
4. According to the Fluor Daniel standard, what piping is deemed rack laden, and what pipe size ranges are involved?
Ans: PIPERACK piping that connects two or more supports. 3" and above.
5. All fabrication shop fabricated piping spools (mark pieces) are shipped in a geometry defined by length, width, and height. Assuming it's a box, there are two situations to avoid with the box and the mark pieces inside. Describe these two situations, as well as the unfavorable outcome if you do not avoid them.
Ans: The piece mark must fit inside the shipping box or it will not be transported. The piece mark's skewed placement within the shipping box may crowd out other piece marks.
6. What is a field weld (FW) and how is it used?
Field Weld is manufactured somewhere other than the fabrication shop. Used to join two marking pieces.
7. Describe three factors to consider when locating a field weld and why they are important.
Ans:
Accessibility: The weld must be in an area that the welder can reach.
Constructability: Prior to welding, the weld must be placed so that the constructors can position the piece mark. Spool piece size to ensure proper fit shipping box and transportable
Economics: Constructed in a location that reduces or eliminates the need for additional scaffolding. Because they are self-sufficient, temporary assistance is not required.
Construction is not required. Made on the smaller side of a reducer, preferably horizontally.
8. What is a field fit-up weld (FFW) and how is it used?
Field Fit is the answer. A weld is one that was created somewhere other than the fabrication shop. The fabrication shop adds more material length to the spool piece. When the location of the connecting point is unknown, this extra length provides field variance for adjustment.
9. What is the construction (fitting type) of: according to Fluor Daniel standard?
Ans: Pipe sizes 2 12" and larger? Butt-weld
2" and smaller pipe size? Sizes of socket welded pipe 2" and smaller? Threaded or screwed
10. What is Fluor Daniel's preferred minimum (not absolute minimum) distance between welds?
3 inches is the answer.
11. What is the absolute smallest distance between welds (only used as a last resort)?
Ans: Pipe Size (NPS) Min. distance b/w welds
1/8” 3/16
1 /4” 1/4
3/8" 5/16
1/2" 7/16
3/4" 1/2
1" 11/16
1 1/4" 13/16
1 1/2" 15/16
2" 1 3/16
2 1/2" 1 9/16
3" 1 3/4
3 1/2" 2
4" 2 1/4
5" 2 3/4
Half the outside diameter of pipe (6” and larger)
12. What do the letters HAZ stand for?
Heat Affected Zone is the answer.
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13. What effect does the HAZ have?
Ans: The material is weakened (pipe wall)
14. How far away is the HAZ from the weld?
Answer: 14" or 1"
15. Why are piping designers concerned about HAZ?
Ans: If two HAZs overlap each other, the pipe may fail.
16. When does the HAZ come into play in threaded construction?
When a threaded connection is seal welded, this occurs.
17. What pressure ratings do forged steel Socket Weld Fittings have?
3000# 6000# is the answer.
18. What pressure ratings do forged steel threaded fittings have?
Ans: 2000#, 3000#, and 6000#
22. What is the technical term for gravity-induced pipe sag, and how does it affect piping design?
Ans: The amount of pipe span is determined by deflection.
23. If one 4" carbon steel pipe is schedule 40 and the other is schedule 80....? Which has the most sag, and why?
Answer: 4 "The sch. 40 has more sag because its wall thickness is less than that of the sch. 80 - the thinner the wall, the shorter the length of the line.
Which is heavier, and why?
4 answers "Because the wall thickness of sch. 80 is greater than that of sch. 40, more material = more weight.
Which has the fewer support points, and why?
Answer: 4 "Because of its thicker wall, sch. 80 can span farther, reducing the number of times support is required.
Drawings of pipeway/Piperack loading/stuffing 24.
Which lines are eligible for loading/stuffing?
Line 3 is the answer "larger that span two or more pipe supports
Why is loading/stuffing done (what are the benefits)?
Ans: It allows for a head start on construction. It reduces the amount of ground area occupied by pipe storage.
25. Variations in line width
When is swage used to change the size of a line?
Ans; When reducing at least one end from or to a socket welded or threaded construction.
When is a butt-weld reducer used to change the size of a line?
Ans: Any horizontal run of pipe with two or more supports within it.
To keep the bottom of the pipe at the same elevation for both line sizes.
When and why do you use eccentric, top flat swages, or reducers?
Ans: A final reduction on a pump end suction line. To keep the pump from cavitating
When and why do you use eccentric, side flat swages, or reducers?
Ans: Used when two equipment connections are so close that after a line size change, the two connecting, adjacent lines interfere with each other.
If they are side by side, the lines may be visible.