6. When do we use Eccentric Reducer

6. When do we use Eccentric Reducer and Concentric Reducer?
-: when we want to avoid liquid or gas trapping inside the flow.
7. Why can’t we use Concentric Reducer at pump suction ? Explain.
-: as answer at no. 6, there will be liquid trap, then this will produce hammer or hard vibration
8. What is the different between Machine Bolt and Stud Bolt?
-: guessing…. stud bolt is used to install two flanges. stud bolt can be tightened from two side.
9. When do we need Dampener, Expansion Joint and Mechanical Snubber? and Why?
-: guessing…. dampener & mech snubber are used when calculation meet unstable supporting.
expansion joint is used to reduce reaction force.
10. Do you know the rule of thumb for piping stress analysis around the pump? Please describe.
-: nope. i know only the design criteria of piping system around pump.
11. Do you know the rule of thumb for piping stress analysis around compressors, turbine and heat exchanger? Please describe.
-: nope.
12. Do you know the rule of thumb for piping stress analysis aroound tower or pressure vessel? Please describe.
-: check of piping settlement between header line and tank/vessel nozzle.
13. What is Steam Tracing?
-: same as heat insulation. to keep the delta temperature inside the pipe.
14. Why Full Bore Pipe is using in connecting pipeline of launcher?
-: in order to avoid locking-trip of pigging
15. When checking Piping Stress Sketch, what parameter you normaly need to check?
-: a. line routing & number
b. dimensions & support locations
c. design/operating temperature & pressure
d. pipe specification
e. code & standard
16. What Code you normaly use for checking the Nozzle load on Compressors, Turbine, Heat Exchanger, Pump, Air Cooler?
-: Do you mean standard ?
API Std 611 = NEMA SM23  Turbine
API Std 617  Centrifugal Compressor
API Std 618  Reciprocating Compressor
API Std 661  Air Fin Cooler
API Std 610  Pump
17. What is the ANSI/ASME Code for dimensional Steel Flanges and Fittings?
-: ANSI B16.9 ?
18. Name the Flange Facing.
-: Raised-Face, Flat-Face & Ring-type Joint
19. Do you know the flange facing called as AARH?
-: nope
20. If you would like to make a branch connection, from which side pipe normaly take the branch connection?
-: gas, vertical 90deg. liquid, horizontal 90deg.
21. Control Valve. What kind of support arangement on Control Valve?
-: put supports closer to the valve. add guide on both supports. add stopper on one of the supports.
22. Why do wee need to provide HPV (High Point Vent) and LPD (Low Point Drain) in Piping?
-: to avoid hammer. this usually happening in pocket line.
23. Do you know about Weldolet, Sockolet? Please Explain.
-: weldolet connects header & branch, welded on the surface, with no pipe branch plug into inside pipe; than that is used in sockolet.
24. What is the normal upstream and downstream straight length of orifice flow meter?
-: 5D – 10D ?
25. What is composite flange?
-: flange made from non-metal material ?
26. Do you know about Insulated Joint? Pleas explain.
-: nope
27. What are insulating gasket kits?
-: no, I don’t know
28. Have you done the analysis of Jacketed Piping?
What do you normaly need to consider during analysis?
-: nope. but, I have received lesson about it.
29. What do you need to take into account when performing stress analysis around Tank?
-: pipe settlement. (data of land-lowering around tank.)
30. What is the relation between Brinnell Hardness Number and Rockwell Hardness Number?
-: can’t remember it … hehehe
31. What is the minimum distance between two welds in a pipe?
-: as maximum pipe long per piece ? 6m ?
32. During fabrication, you observed that one small crack has appeared on a fresh plate, what type of measure you will take to obtain desired quality with minimum wastage?
-: i don’t get the idea…
33. Describe the different types of destructive and non-destructive tests?
-: same as no. 32
34. What is PWHT? Why is it required?
-: Post Weld Heat Treatment.
35. What is the minimum thickness of pipe that requires stress relieving to be done as per ASME B31.3?
-: i don’t know
36. What is NACE MR-0175 for?
-: i don’t know
37. Hydrotest Pressure. Do you know how to calculate the test Pressure? Please describe.
-: for B31.3 pipe, hydrotest pressure = 1.5 x MAOP/MAWP for rating 300 & below. for 400# & above, use 1.5 x design pressure.
for B31.8 pipe, HT pressure = 1.1 to 1.5 x design pressure.
38. Do you know heat exchanger? What fluid in Shell Side and what fluid in Tube Side?
-: hot gas or fire in shell and steam-water in tube.
39. Do you know Glandless Piston Valves. Where these valves are used?
-: nope
40. Have you done estimation of piping system during proposal? How do you do that?
-: by separating first, all line number into critical lines and non-critical ones. then connect all critical lines into a system and made them in amount of calculation numbers.
41. Why do we need to do Stress Analysis?
-: to ensure safety in piping design, in its systems.
42. What are the steps in piping stress analysis?
-: gather all data needed, make pipe stress sketch (put nodal numbers in it) as per critical line list, calculate to analyze, manually (simplified method) or by computer software, reporting.
43. Tell me about the type of the stressess during normal operation?
-: primary (sustain) and secondary (thermal)
44. What do you need to prepare and and then to input into CAESAR II or Autopipe for Stress Analysis?
-: Code used, design pressure, design/operating temperature, test pressure, material properties (size, material type, sch./w.t, CA, SY/SC/SH, poisson ratio, pipe density), fluid density, insulation data (type & density), support location, equipment data, environment data.
45. What type of loads available in the stresss analysis calculation? Please Explain.
-: sustain load : inside pressure, pipe (incl. valves, flanges, etc.) weight
thermal load : ambient, design & operating temperatures
46. Do you know about Load Cases in Stress Analysis? Please Explain.
-: normal are sustain, operating & expansion load.
additional are environtment load & mechanical load.
47. What is Load Case for Sustained Load, Expansion Load, Stress Range, Occasional Load, Spring?
-: sustain : weight (specific gravity/density) + inside pressure
expansion : delta temperature
stress range : — i don’t know —
occasional : wind, earthquake/seismic, external force, slug/hammer, reaction froce of PSV
48. What is the failure theory under ASME B31.3?
-: SL (sustain) >< SY
49. Do you know what type of piping failure during its operation?
-:
50. What is the desired life cycle for piping during operation?
-: based on ASME B31.3, around 7000 cycles
51. How to calculate thermal expansion in a pipe?
-: delta L = exp. coeff. x delta T x L
52. Do you know SIF (Stress Intensification Factor)? Explain and give some examples?
-: stress max value occuring because of material repositioning.
ex. : tee, ellbow
53. Pipe Support. What is the pipe support span?
-: distance between two pipe supporting point.
54. What is the criteria to determine the span of pipe support?
-: depend on size + wall thk. & fluid density
55. How do we decide an anchor point at Expansion Loop on pipe rack?
-: near to end of pipe rack.
56. What is the steam out condition?
-: i don’t know… :(
57. On Heat Exchanger, where do you provide an anchor support and slotted support? and Why?
-: support near to inlet & outlet nozzle should be slotted support. then another one is anchor/fixed support.
58. Do you know PTFE on Support? Why we need that?
-: when we don’t want over-force (vertical and/or horizontal) acting at pipe support.
59. Tell me about spring support.Why we need it? And how many type of spring support? Explain as much as you can.
-: Spring support is needed to absorb over load (force) or over displacement occured becuse of restrained-pipe.
type of spring : variable & constant
variable is used when there is sufficient distance around pipe, so that the spring support can travel thoroughly. this is used for absorp over-force reacted at rigid-type support.
constant is used when there is only small dimension of distance. this is used as variable plus stabilize center position of pipe in the system.