PIPING ENGINEERING INTERVIEW QUESTIONS PART 1
1. Q:-What is the ASME code followed for design of piping systems in Process?
Answer:
ASME B31.5
ASME B31.5
2. Q:-Normally where do we use the following? a. Eccentric
reducers. b. Concentric reducers.
Answer:
- · Eccentric reducers = Pump suction to avoid Cavitation, To maintain elevation (BOP) in rack.
- · Concentric reducers = Pump discharge, vertical pipeline etc.
3. Q:-What is the purpose of providing Graphite Pads in
supports below shoes?
Answer:
To reduce the friction factor. The co-efficient of friction for Graphite Pads is 0.1
To reduce the friction factor. The co-efficient of friction for Graphite Pads is 0.1
4. Q:-How can flanges be classified based on Pressure temperature
ratings?
Answer:
Flanges are classified based on pressure temperature ratings as: A. 150 B. 300 C. 400 D. 600 E. 900 F. 1500 G. 2500 Pressure temperature rating carts in the standard ASME16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.
Flanges are classified based on pressure temperature ratings as: A. 150 B. 300 C. 400 D. 600 E. 900 F. 1500 G. 2500 Pressure temperature rating carts in the standard ASME16.5 specify the non-shock working gauge pressure to which the flange can be subjected to at a particular temperature.
5. Q:-How the Gaskets
are classified based on the type of construction?
Answer:
Based on the type of construction, gaskets are classified as:
Based on the type of construction, gaskets are classified as:
A. Full face.
B. Spiral wound metallic.
C. Ring type.
D. Metal
jacketed.
E. Inside bolt circle.
6. Q:-What is the difference between Pipe and Tube?
Answer:
Pipe is identified by NB and thickness is defined by Schedule whereas Tube is identified by OD.
Pipe is identified by NB and thickness is defined by Schedule whereas Tube is identified by OD.
7. Q:-From which size on wards NB of pipe is equal to OD of
Pipe?
Answer:
From the size 14” and onwards NB = OD of pipe.
From the size 14” and onwards NB = OD of pipe.
8. Q:-What is the
basis of using of short radius & long radius elbow?
Answer:
1D( “D” is the diameter of the pipe.) and 1.5D (“D” is the diameter of the pipe)
1D( “D” is the diameter of the pipe.) and 1.5D (“D” is the diameter of the pipe)
9. Q:-From which side of pipe will you take a branch
connection?
Answer:
When Fluid is Gas, Air or Steam and Cryogenic Service – Topside. When Fluid is Liquid – Bottom Side.
When Fluid is Gas, Air or Steam and Cryogenic Service – Topside. When Fluid is Liquid – Bottom Side.
10. Q:-Why do we provide High Point Vent (HPV) and Low Point
Drain (LPD) in piping?
Answer:
HPV – for removing Air during Hydro-test.
LPD – for draining water after conducting Hydro-test.
HPV – for removing Air during Hydro-test.
LPD – for draining water after conducting Hydro-test.
11. Q:-What is the function of valves?
Answer:
A. Isolation.
B. Regulation.
C. Non-Return.
D. Special purpose.
A. Isolation.
B. Regulation.
C. Non-Return.
D. Special purpose.
12. Q:-How the valves are classified based on end
connection?
Answer:
A. Screwed ends.
B. Socket ends.
C. Flanged ends.
A. Screwed ends.
B. Socket ends.
C. Flanged ends.
13. Q:-What should be the radius of long radius elbow?
Answer:
1.5D (Where “D” is the diameter of the pipe)
1.5D (Where “D” is the diameter of the pipe)
14. Q:-What should be the radius of short radius elbow?
Answer:
1D(Where “D” is the diameter of the pipe.)
1D(Where “D” is the diameter of the pipe.)
15. Q:-Which American standard is referred for selection of
following piping element? a. Flanges b. Butt Welded fittings c. Gasket d.
Socket and Threaded fittings e. Valves f. Pipes.
Answer:
- · Flanges :- I. ASME B16.1 : Cast iron pipes flanges and flanged fittings. II. ASME B16.5 : Carbon steel pipes flanges and flanged fittings. (Up to 24”) III. ASME B16.47 : Large Diameter steel flanges. (Above 24”)
- · Butt welded fittings:- I. ASME B16.9 : Steel butt welding fittings. II. ASME B16.28 : – Butt-welded short radius elbows and returns bends.
- · Gasket :- I. ASME B16.20 / API -601: Metallic gaskets for pipe flanges- Spiral wound, Octagonal ring Joint and Jacketed flanges. II. ASME B16.21 : Non metallic gasket.
- · Socket & Threaded fittings :- I. ASME B16.11 : Forged steel socket welding and threaded fittings.
- · Valves :- I. ASME B16.10 : Face to face and end to end dimension of valves. II. ASME B16.34 : – Flanged and butt-welded ends steel valves (Pressure and Temperature ratings) except Ball, Plug and Butter fly Valves.
- · Pipes :- I. ASME B36.10 : Welded and Seamless wrought iron pipes. II. ASME B36.19 : – Stainless steel pipes.
16. Q:-What is the minimum distance to be maintained between
two welds in a pipe?
Answer:
The thumb rule is that the minimum distance between adjacent butt welds is 1D. If not, it is Never closer than 1-1/2″. This is supposedly to prevent the overlap of HAZs. Minimum spacing of circumferential welds between centerlines shall not be less than 4 times the pipe wall thickness or 25 mm whichever is greater.
The thumb rule is that the minimum distance between adjacent butt welds is 1D. If not, it is Never closer than 1-1/2″. This is supposedly to prevent the overlap of HAZs. Minimum spacing of circumferential welds between centerlines shall not be less than 4 times the pipe wall thickness or 25 mm whichever is greater.
17. Q:-What are the types of check valves based on check
mechanism?
Answer:
Check valves are divided into two types based on check mechanism as:
Check valves are divided into two types based on check mechanism as:
- · Lift check valve.
- · Swing check valve.
18. Q:-What are the Criteria for Pipe Supporting?
Answer:
Following are the points, which should be taken into account for proper supporting:
Following are the points, which should be taken into account for proper supporting:
- · Load of bare pipe + fluid + insulation (if any).
- · Load of bare pipe + water fill.
- · Load of valves and online equipment and instrument.
- · Thermal loads during operation.
- · Steam out condition, if applicable.
- · Wind loads for piping at higher elevation, if required.
- · Forced vibration due to pulsating flow.
- · Bare pipe with size above 12” shall be supported with Pad or Shoe.
19. Q:-How can flanges be classified based on Pipe
Attachment?
Answer:
Flanges can be classified based on pipe attachment as:
Flanges can be classified based on pipe attachment as:
- · Slip – on. : – The Slip-on type flanges are attached by welding inside as well as outside. These flanges are of forged construction.
- · Socket Weld. : – The Socket Weld flanges are welded on one side only. These are used for small bore lines only.
- · Screwed. : – The Screwed-on flanges are used on pipe lines where welding cannot be carried out.
- · Lap Joint. : – The Lap Joint flanges are used with stub ends. The stub ends are welded with pipes & flanges are kept loose over the same.
- · Welding Neck. : – The Welding neck flanges are attached by butt welding to the pipe. These are used mainly for critical services where the weld joints need radio graphic inspection.
20. Q:-What is the difference between variable spring hanger and constant spring hanger?
Answer:
- · Variable spring Hanger: – As the name itself indicates the resistance of the coil to a load changes during compression.
- · Constant spring Hanger: – Constant spring hanger provides constant support force for pipes and equipment subjected to vertical movement due to thermal expansion.