PIPING INTERVIEW QUESTIONNAIRE
1. What factors to consider for site selection?
Ans : District classification, Transportation facilities, Manpower
availability, industrial infrastructure, community infrastructure, availability
of raw water, effluent disposal, availability of power, availability of
industrial gas, site size and nature, ecology and pollution.
2. What are different standards?
Ans : Most commonly use standards are as follows:
Sr. Standard Description
1. ANSI B18.2 Square and hexagola head bolts and nuts
2. ANSI B16.3 Malleable iron threaded fittings
3. ANSI B16.4 Cast iron threaded fittings.
4. ANSI B16.9 Steel buttwelding fittings
5. ANSI B16.11 Forged steel socketwelding and threaded fittings
6. ANSI B16.25 Buttwelding ends
7. ANSI B16.28 Short elbow radius and returns
8. MSS-SP-43 Stainless steel buttweld fittings
9. MSS-SP-83 Pipe Unions
10. API 605 Large diameter carbon steel flanges
11. ANSI B16.1 Cast iron pipe flanges and flanged fittings
12. ANSI B16.5 Steel pipe flanges and flanged fittings
13. ANSI B16.47 Large diameter steel pipe flanges and flanged fitts.
14. ANSI B16.20 Ring joint gaskets and grooves for pipe flanges
15. ANSI B16.21 Non metallic gaskets for pipe flanges
16. API 601 Metallic gasket for refinery piping.
17. API 5L Specification for line pipe.
18. ANSI B16.10 Welded and seamless wrought steel pipes
19. ANSI B36.19 Welded and seamless austenitic stainless steel pipe
20. ANSI B16.10 Face to face and end to end dimensions of valves
21. ANSI B16.34 Steel valves, flanged and buttwelding ends.
3. What are various temporary closures for lines?
Ans : Line blind valve, line blind, spectacle plate, double block and bleed,
blind flanges replacing a removable spool.
4. Where jacked screwed flange is used ?
Ans : For spectacle discs, one flange is jacked screw flange. This flange
has two jacked screws 180 degree apart which are used to create
sufficient space between flange for easy removal and placement of line
blind or spectacle blind.
5. What is double block and bleed?
Ans : Two valves with bleed ring in between with a bleed valve connected
to the hole of bleed ring.
6. Where blind flange is used ?
Ans : It is used with view to future expansion of the piping system, or for
cleaning, inspection etc.
7. What are crude oil ranges?
Ans : Crude oil BP Range: 100F-1400F, lightest material: Butene below
100F, Heavier materials- upto 800F, Residue above 800F.
8. What is batch shell process?
Ans : feed, heat,condense,heat more,condense, low quality.
9. What are types of towers?
Ans : Stripper, Vacuum tower, trayed, packed towers.
10. What is chimney tray?
Ans : It’s a solid plate with central chimney section, used at drawoff
sections of the tower.
11. What factors to consider while setting tower elevation?
Ans : NPSH, Operator access, Maintenance access, Minimum clearance,
reboiler type , common area, type of support, Tower dimensions, type of
head, bottom outlet size, foundation details, minimum clearances.
12. How to located tower maintenance access nozzles ?
Ans : At bottom, top and intermediate sections of tower, must not be at
the downcomer section of tower and in front of internal piping.
13. How to located feed nozzle ?
Ans : Must be oriented in specific area of tray by means of internal
14. How to located temperature and pressure instruments ?
Ans : Temperature in liquid space, at downcomer side and pressure in
vapor space, in area except downcomer sector.