QUESTIONS AND ANSWERS


1. What are your strengths?
2. What are your weaknesses?
3. Why are you interested in working for [insert company name here]?
4. Where do you see yourself in 5 years? 10 years?
5. Why do you want to leave your current company?
6. Why was there a gap in your employment between [insert date] and [insert date]?
7. What can you offer us that someone else can not?
8. What are three things your former manager would like you to improve on?
9. Are you willing to relocate?
10. Are you willing to travel?
11. Tell me about an accomplishment you are most proud of.
12. Tell me about a time you made a mistake.
13. What is your dream job?
14. How did you hear about this position?
15. What would you look to accomplish in the first 30 days/60 days/90 days on the job?
16. Discuss your resume.
17. Discuss your educational background.
18. Describe yourself.
19. Tell me how you handled a difficult situation.
20. Why should we hire you?
21. Why are you looking for a new job?
22. Would you work holidays/weekends?
23. How would you deal with an angry or irate customer?
24. What are your salary requirements? (Hint: if you’re not sure what’s a fair salary range and compensation package, research the job title and/or company on Glassdoor.)
25. Give a time when you went above and beyond the requirements for a project.
26. Who are our competitors?
27. What was your biggest failure?
28. What motivates you?
29. What’s your availability?
30. Who’s your mentor?
31. Tell me about a time when you disagreed with your boss.
32. How do you handle pressure?
33. What is the name of our CEO?
34. What are your career goals?
35. What gets you up in the morning?
36. What would your direct reports say about you?
37. What were your bosses’ strengths/weaknesses?
38. If I called your boss right now and asked him what is an area that you could improve on, what would he say?
39. Are you a leader or a follower?
40. What was the last book you’ve read for fun?
41. What are your co-worker pet peeves?
42. What are your hobbies?
43. What is your favorite website?
44. What makes you uncomfortable?
45. What are some of your leadership experiences?
46. How would you fire someone?
47. What do you like the most and least about working in this industry?
48. Would you work 40+ hours a week?
49. What questions haven’t I asked you?
50. What questions do you have for me?

1.What is the difference between Pipe and Tube?

Ans: Pipe is identified by NB and thickness is defined by Schedule whereas Tube is identified by OD.

2.From which size onwards NB of pipe is equal to OD of Pipe?

Ans: From the size 14” and onwards NB = OD of pipe.

3.What is the difference between machine bolt and stud bolt?

Ans: Machine bolt has a head on one side and nut on other side but stud bolt have nuts on both sides.

4.What is soluble dam?

Ans: Soluble dam is a water-soluble material used for restricting the purging gas within the pipe.

5. While welding of pipe trunion to pipe/reinforcement pad you have to put a hole or leave some portion of welding why?

Ans: For venting of hot gas which may get generated due to welding

6. What should be the radius of long radius elbow?

Ans: 1.5D (Where “D” is the diameter of the pipe)

7. Concentric reducer is used in pump suction. (Yes / No). Explain.

Ans: No. Air pockets may form if concentric reducer is used at pump suction, which results in Cavitation, and cause damage to Pump. To avoid this problem, Eccentric Reducer with Flat Side Up (FSU)is used in Pump Suction.

8. What is the thumb rule to calculate spanner size for given bolt?

Ans: 1.5 x diameter of Bolt

9. What is the thumb rule to calculate Current required for Welding?

Ans: Current (Amp) = [ Diameter of Electrode (mm) X 40] + 20

10. What is steam tracing? How do we decide the location of SSM & CRM.

Ans: Steam Tracing is a process which is used to prevent the fluid passing through a process line from freezing by keeping the temperature high enough for free flow of fluid and thus maintaining pumpability. SSM and CRM are generally located 38M max for open system and 24 M max for closed system when we use LP Steam up to 3.5 kg/sq cm. as a heating media.

11. Which piping items will you drop down before conducting Flushing and Hydrotest?

Ans: Items like Control Valve, Orifice plates, Rotameters, safety valves , Thermowells are dropped or replaced with temporary spools before hydro test.

12.Why do we provide a Dampner in the Piping of Reciprocating Pump?

Ans: To take care of Pulsation.

13.Why do we provide Full Bore Valve in connecting pipeline of Launcher / Receiver?

Ans: For Pigging.

14. Which parameters will u check during checking Piping Isometrics?

Ans: Bill of Material, Pipe Routing wrt GAD, Supporting arrangement , details of insulation, hydrotest pressure, painting specs and provision of Vent and Drains at appropriate locations.

15. How can flanges be classified based on facing?

Ans: Flat Face b. Raised Face c. Tongue and groove d. Ring type joint

16. What do you mean by AARH (Flange Finish)?

Ans: Arithmetic Average Roughness Height.

17. Which are the different types of Gaskets?

Ans: Full Face, Spiral Wound, Octagonal Ring Type, Metal Jacketed and Inside Bolt Circle

18. What should be the relative hardness between the RTJ gasket and flange groove?

Ans: For a RTJ flange , the joint ring should have a 30-40 Vickers hardness less than that of the mating face of flange.( Brinnel hardness for RTJ groove shall be 20-50 BHN more than the corresponding gasket hardness)

19. From which side of pipe will you take a branch connection?

Ans: When Fluid is Gas, Air or Steam and Cryogenic Service – Topside. When Fluid is Liquid – Bottom Side.

20. Why don’t we take a branch for Cryogenic Service from bottom side though the fluid is in liquid state?

Ans: There is the chance of Ice formation during normal operation and since ice flows from the bottom of the pipe it will block the branch pipe connection.

21.Why do we provide Drip Leg in Steam Line?

Ans: To remove Condensate when there is a rise in the pipe along the flow direction. If we do not provide the drip leg in steam line, the condensate which forms inside the pipe will result in Water Hammer effect causing damage to piping system.

22. How do you support any small size HDPE/PVC (Plastic) pipe?

Ans: It should be supported continuously by using channel or Angle so that line should not Sag or fall from the sleeper/rack due to uneven expansion because of Hot Temp.

23.What is the normal upstream and downstream straight length of orifice flow meter?

Ans: Upstream - 15D Downstream - 5D.

24.What are the different hardness tests carried out?

Ans: Brinell Hardness Test, Rockwell Hardness test ,Vicker Hardness Test

25. Describe different types of destructive and non-destructive tests?

Ans: DESTRUCTIVE TEST: Bend test, Tensile test, Impact test, and Hardness test.NON-DESTRUCTIVE TEST: DPT, MPT, Radiography and ultrasonic test.

26. What is mean by ‘PWHT’? Why it is required?

Ans: “POST WELD HEAT TREATMENT” This is done to remove residual stress left in the joint which may cause brittle fracture.

27. What are Glandless Piston Valves. Where these are used?

Ans: Glandless piston valves are maintenance free valves used in the steam service.

28. What is the Code for Sour Service?

Ans: Code for Sour Service is NACE (NACE MR – 0175) NACE: National Association of Corrosion Engineers

29. What do you mean by Insulated Joint?

Ans: Insulating Joints are a prefabricated, non separable union used to isolate specific sections of Pipelines to prevent corrosion caused by stray electrical currents or interference from other pipelines and power transmission cables.

30. How do you calculate the pipe spacing?

Ans: Pipe Spacing (mm) = ( Do + Dt ) / 2 + 25mm + Thickness of Insulation (mm). Where: D0 : OD of Small size Pipe (mm). Dt : OD of Flange of Large size Pipe (mm).

1. What is the objective of stress analysis?

Ans: To ensure that the stresses in piping components in the system are within allowable limits.
To solve dynamic problems developed due to mechanical vibration, fluid hammer, pulsation, relief valves, etc.
To solve problems associated due to higher or lower operating temperature such as a) Displacement stress range b) Nozzle loading on connected equipments c) Pipe displacements d) Loads & moments on supporting structure

2. What are the steps involved in stress analysis (or any stress package carries out)?

Ans: Identify the potential loads that the piping system would encounter during the life of the plant.
Relate each of these loads to the stresses and strains developed.
Get the cumulative effect of the potential loads in the system.
Decide the allowable limits the system can withstand without failure as per code.
After the system is designed to ensure that the stresses are within safe limits.

3. What are the different types of stresses that may get generated within pipe during normal operation?

Ans: Axial Stresses (Tensile / Compressive), Shear Stresses, Radial Stresses, Hoopes Stresses.

4. What are the sources of sustained loads generated in piping system?

Ans:a. Pressure b. Dead weight of Pipe and attachments Sustained load is calculated as Weight of Pipe with Fluid + Pressure load + Load due to springs W+P1

5. How do you calculate the operating load?

Ans: W+P1+T1 , T1 – Load due to thermal expansion

6. Give some Examples for occasional Loads.

Ans: Wind, wave & earthquake

7. Mention some of Primary Loads (Have their origin in force)

Ans: Dead Weight, Pressure, forces due to relief or blowdown, force due to water hammer effects

8. What is desired life cycle for Piping in operation?

Ans: Desired life cycle for Piping in operation is 20 Years (7000 Cycles). The normal no. of cycles for which the displacement or thermal stresses are designed is 7000 cycles

9. How do you calculate the stress developed due to thermal expansion?

Ans: Stress developed = E x e/L
E – Young’s Modulus
e- Increase in length due to thermal expansion
L – Original Length of the pipe

10. How do you calculate the thermal expansion in a pipe?

Ans: e=  x L x Rise in Temperature.

11. What are the things to be taken care of while doing pump piping?

Ans: Pipe strain may distort equipment alignment, so welding should be done in such a way that the tension in the equipment flange is minimised

12. What is the Steam out condition?

Ans: Hydrocarbon lines are usually subjected to Steam Out condition and designed and anlysed at low pressure steam design temperature (should be minimum 180 degree C) or design temp. whichever is more . Lines having negative design temp. is analysed for both conditions seperately.

13. Where do you provide Anchor and Slotted Support of Heat Exchanger?

Ans: Anchor support of Heat exchanger is provided on the side from which Tube Bundle will be pulled out for the purpose of Maintenance work also it is based on the growth of the connecting piping as exchanger should grow with the piping.

14. What do you mean by Hoop Stresses and how do you calculate it?

Ans: Stresses which are generated circumferancially due to the action of Internal pressure of pipe are called as Hoop Stress. It is calculated by
Hoop Stress (Sh) = Pdo / 4t
Where P = Force Acting from Inside.
Do = OD of Pipe. t= Pipe Thickness.

15. How does Hoop Stress affect the system?

Ans: As per membrane theory for pressure design of cylinder, as long as hoop stress is less than yield stress of Moc, the design is safe. Hoop stress induced by thermal pressure is twice the axial stress (SL). This is widely used for pressure thickness calculation for pressure vessel.

16. What is the purpose of providing Graphite Pads in supports below shoes?

Ans: To reduce the friction factor. The co-efficient of friction for Graphite Pads is 0.1

17. How is piping to Tank inlet nozzle is supported and why?

Ans: Piping to Tank Nozzle is supported with Spring type support (first support from Nozzle) in order to make the Nozzle safe from the loads which occurs due to the displacement of pipe (thermal expansion of pipe / tank material, tank settlement etc).

18. What are the two types of flexible spring hangers?

Ans: 1. Constant Spring and 2. Variable Spring

19. How much should be the difference between the load which will be taken by Variable Spring Hanger during Cold and Hot condition of Pipe?

Ans: It should be Maximum 25% of Load for which Spring is designed.

20. What is WRC 107 / WRC 297?

Ans: Localised stresses at Nozzle to Shell is calculated by WRC 107 / 297 and these computed stress values shall be limited in accordance with ASME Sec VIII for Pressure Vessels.

21. What is the purpose of expansion bellows?

Ans: Expansion bellows are used absorb axial compression or extension, lateral shear or angular torsion developed in the pipes (specially near nozzles)

22. What should be the material of shoes for supporting AS pipes & why?

Ans: If CS shoes are used Pad in contact with the pipe to be of Alloy steel to avoid dissimilar welding at pipe. To avoid alloy steel welding and dissimilar welding fabricated clamps either of CS or SS can be used.

23.What is the difference between machine bolt and stud bolt?

Ans: Machine bolt has a head on one side and nut on other side but stud bolt have nuts on both sides.

24. What is the allowable stress range for CS pipes.

Ans: 2070 kg/cm2.

25. What are the Insulation material used for piping systems.

Ans: Fibrous – Rock & Glass Wool.
Rigid - Calcium silicate, Polyisocyanurate, cellular Glass