Here are the answers , if any one has different opinion or idea share with me.1. Can you explain in detail three or more major differences between code ANSI B31.1 and code ANSIB31.3?

Answer: There is only one major difference between the two, B31.1 is for Power Piping and B31.3 is forRefinery/Chemical Plant Piping.2. There is a power plant inside a Process refinery.

Where exactly the ANSI B31.1 & ANSI B31.3 scopebreak occurs?

Answer: Based on my experience there were two cases. Case #1, B31.1 stopped at the Power Plant Unit block valves. Thus all piping inside the Power Plant was B31.1.

Case #2, B31.1 stopped at the equipment(Boiler) isolation block valves and then all other piping was B31.3. This is normally the choice of theowner/operator/client.3.

Which of the following piping system is more health hazardous. A) Fuel oil piping b) Process pipingwith Caustic c) process piping with HF acid d) Sulphuric acid piping.

Answer: c) process piping with HF acid4.

There is a steam piping with low pocket but without steam trap. What will be worst consequence of this layout?

Answer: There will be a build up of condensate to the point that a slug will be pushed by the steam flow. This slug of condensate will cause “water hammer” and could rip the piping apart

.5. In what circumstance, the reducer of a pump suction piping will be in bottom flat position. Explain why the reducer should be so.

Answer: Still Needs a Proper Explanation for the this answer.6. A P&ID shows a spec break (at Flange) between carbon steel & stainless steel specification.

What additional arrangements you have to make for that dissimilar material flange joint?

Answer: Use the Gasket and bolts from the SS spec.7. A stainless steel piping specification mentions Galvanized carbons steel bolts. What is your firstreaction ti this and how do you rectify it?Answer: If that is what the Spec call for then that is what I am supposed to use. But, I would ask the Piping Material Engineer (PME) why he/she specified galvanized bolts.8. How many types of piping specialty items do you know? Why it is called a piping special? Why not we include them in standard piping specification.

 Answer: I could possibly count 50 or more depending on the PME and how the piping material specswere developed. They are called them SP items because they are NOT written into the normal PipingMaterial (Line Class) Specifications. They are not included because they are

normally of limited use,purchased from a limited product line vendor and are often after thoughts.

9. Draw a typical steam trap station layout and explain why the existence of a by-pass line around thetrap is not a good idea, when the condensate is returning to a condensate header?Answer: (No drawing) It is not advisable to have a bypass around a steam trap because the block valvecould be left open and defeat the purpose of the trap.

10. Explain what is a “Double block & Bleed” valve? Why we need a bleed valve? When do we use this? Answer: The primary purpose of a “Double Block & Bleed” is Safety. However it is not fail safe. The nextbetter “Safety” set-up would be Double Block Valve with a Spec Blind between the valves. The higherlevel of safety would be double block valves with a removable spool for absolute isolation.11. In a typical tie-in where should the spectacle blind be inserted? a) after block valve and towardsexisting plant b) before block valve and towards new plant. Explain why.Answer: The Spec Blind shall be placed on the Unit side of the Unit Block valves. This placement allowsfor the closing of the Unit isolation block valve, the unit side is depressured and drained. Then the specblind can be installed for isolation of the unit.

12. “Stress intensification factor (SIF)” Where do we use this? Explain this term. How many types of these SIF’s exist? Answer: Stress Intensification Factor (SIF) is a multiplier on nominal stress for typically bend andintersection components so that the effect of geometry and welding can be considered in a beamanalysis. Stress Intensification Factors form the basis of most stress analysis of piping systems. As for thequantity, ask a Stress Engineer.

13. When all design parameters are same, whose thermal expansion is higher among the following? A)Carbon steel b) Stainless steel c) Duplex steel d) Cast Iron e) Galvanized Carbon steel.

Answer: b) Stainless steel

14. In a hose station the hose couplings used for water, air & steam should be different type. Do youagree? Explain your view.

Answer: I agree. If they are all the same then the hoses can be connected to the wrong services andcould result in the injury of an operator (i.e.: thinking the hose is connected to water when it isconnected to steam).

15. What is your view on the usage of Metallic expansion joints? When they become necessary and when they could be avoided?

 

Answer: I do everything I can as a piping designer to avoid the use of all types of expansion joints.Expansion joints are always the weakest point in any system where they are used.

16. A water cooler heat exchanger, located on a 20 m high structural platform. Water header is locatedu/g. What precaution do you take, in case of Pressure loss in cooling water header?Answer: I do not understand this question it does not appear to be a piping issue. I would assume thatthe cooling water system has a (loss of) pressure sensor and the plant shut-down alarms and sequencewould be activated.

17. In what order do you arrange the pipes in the Pipe rack and why? How much % of area should bereserved for Future expansion? Specify a range.

Answer: The largest hottest lines on the outside edge of the pipe rack working in with cooler lines intowards the middle of the rack. This allows the longer loop legs as you lay the loops back over the otherlines to the other side of the rack and back. The lower temperature loops would be “nested” inside thelarger, hotter loops.“Future rack space” is normally at the direction of the Client. It may be anything from 0% to as much as25%.

18. When a utility line (like condensate or water etc) is connected permanently to a process piping whatprecaution we have to take to avoid cross contamination?Answer: Option #1, double block valve with a drop-out spool.Option #2, Double block valve with a spec blind.Option #3, double block valves with a bleed valve.

19. A air fin cooler (2 air coolers with each having 2 inlet nozzles) needs a Typical piping arrangement.How many types of piping arrangement is possible.Answer: There are a number of ways to pipe a Fin-Fan cooler depending on what the P&ID call for?

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