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By : Ramakrishna Perumal, Sr. Engineer, Technicas Reunidas
Industry : Oil & Gas
Keywords :


Activity:  2 comments  1331 views  last activity : 07 06 2010 20:18:04 +0000

35. Why do we provide High Point Vent (HPV) and Low Point Drain (LPD) in piping?



HPV – for removing Air during Hydro-test

LPD – for draining water after conducting Hydro-test.

36. Which standard and codes will you refer while designing the piping?




Following are the codes and standards –

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API Std 610 : Centrifugal Pumps for Petroleum, Heavy Duty Chemical and

Gas Industry Services.

ANSI/NEMA SM 23 : Steam Turbines for Mechanical Drive Services.

API Std 617 : Centrifugal Compressor for Petroleum, Chemical and Gas

Industry Service.

EJMA : Expansion Joints Manufacturer’s Association.

OISD – 118 : Layout for Oil and Gas Installations.

IBR : Indian Boiler Regulations.

NACE MR – 0175 : Sulfide Stress Cracking Resistant Metallic Materials for Oilfield


NACE MR – 0284 : Evaluation of Pipeline and Pressure Vessel Steel for

Resistance to Hydrogen Induced Cracking.

NACE TM – 0177 : Laboratory Testing of Metals for Resistance to Sulfide Stress

Cracking in H2S Environment.

37. What do you mean by IBR and Which lines comes under IBR purview?




IBR: Indian Boiler Regulation Act.

Steam lines with conditions listed bellow comes under IBR purview –

Lines for which design pressure is 3.5 kg/sq cm and above.

Line size above 10" having design pressure 1.0 kg/sq cm and above.

Boiler feed water lines to steam generator, condensate lines to steam generator and

flash drum.

38. What are Weldolet and Sockolet? And where they are used?




Weldolet and Sockolet are basically self reinforced fittings.

Weldolet is used for Butt weld branch connection where standard tee is not

available due to size restrictions and the piping is of critical / high pressure service.

Sockolet is used for socket welding branch connection, which require reinforcing


39. What is the MOC for Superheated high pressure Steam Lines?





A 335 Gr P I / P II

Composition : 0.5 Mo(P1) /1.25 % Cr-.5 Mo(P11)

40. What is the normal upstream and downstream straight length of orifice flow


Answer : Upstream - 15D Downstream - 5D

41. What are the essential data required for the preparation of equipment layout?

Ans : 1)PFD and P&ID 2. Project Design data 3. Equipment Sizes & Buildings

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42. What are the various statutory requirements to be considered during layout?

State Industrial Development Corporation (SIDC)

Central / State Enviromental Pollution Control Boards (PCBS)

Factory Inspectorate

State Electricity Boards

Chief Controller of Explosives (CCOE)

Static & Pressure Vessel Rules (SMPV)

Tariff Advisory Committee

Aviation Laws

Chief Inspector of Boilers (CIB)

Oil Industry Directorate (OISD)

Food and Drug Administartion (FDA)

Ministry of Environment and Forest (MoEF)

43. What do you mean by Composite Flange?

The flange that is made up of more than one MOC is called a Composite flange.

a. Lap Joint Flanges

Insert Flanges are a specialty in the arena of pipe size flanges and consist of two parts

- the insert and the flange ring. The flange ring is the outer part of the insert flange

assembly, containing the bolt holes.

The two piece construction of the insert flange also offers the economy of matching the

insert material to the process pipe (usually some corrosion resistant alloy) while the

outer flange ring may be manufactured from steel. When the environment req uires the

flange ring to be made of some alloy the rotating feature is still maintained.

b. RF flanges with Raised of one MOC and rest of the flange with different MOC

c. RF blind flange with an overlay of 90/10 Cuni for Sea water service.

44. What do you mean by Insulated Joint?



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.


45. What are Insulating Gasket Kits?



Insulation gasket kits are designed to combat the effects of corrosion often found

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in flanged pipe systems. Galvanic corrosion between dissimilar metal flanges (flow of

currents) , flange insulation associated with cathodic protection of underground piping

are also the places where Insulating gasket kits are used. It consists of


Neoprene faced Phenolic /Glass Reinforced


Insulation sleeve

Reinforced Phenolic/Nylon/Polyethylene/(G10)

Insulation washer

Reinforced Phenolic/Nylon/Polyethylene/(G10)

Plated Washer

Electro plated steel washer

46. What do you mean by Jacketed Piping?


47. What is the min. distance to be maintained between two welds in a pipe

The rule of thumb 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 HAZ s.

Minimum spacing of circumferential welds between centrelines shall not be less than 4

times the pipe wall thickness or 25 mm whichever is greater.

48. What are the different hardness tests carried out?


Brinell Hardness Test

Rockwell Hardness test

Vicker Hardness Test

49. What is the relation between Brinell Hardness No and Rockwell Hardness



22 HRC (Rockwell Hardness) = 238 BHN (Brinell Hardness No)


Piping which is recognized as providing the most

uniform application of heat to the process, as well

as maintaining the most uniform processing

temperatures where steam tracing is not capable of

maintaining the temperature of fluid constant.

Usually used for molten sulphur, Polymers service.

1.During fabrication you observed that one small crack has appeared on a fresh

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plate, what type of measure you will take to obtain desired quality with minimum



First identify the exact length of crack by DP test. Drill on the end point to resist further

crack. Remove the crack portion by cutting the strip.


i. What are the fittings required for fabrication of the isometric.

ii. Find out the length of pipe required.

iii. Do joint numbering and show the following things in the isometric.

a) Shop


b) Field


c) Spool




Drilling Point


N 173884

EL +104280

EL +103530

EL +102630

N 1736500

E 3182000


Field Joint







  Commented by  Vineet Prakash, Sales/BD Manager, Tata Power    | 11 06 2009 06:36:34 +0000
Nice questionnaire Mr.Perumal, really very informative. Thanks for sharing...
  Commented by  Vineet Prakash, Sales/BD Manager, Tata Power    | 11 06 2009 06:36:21 +0000
Nice questionnaire Mr.Perumal, really very informative. Thanks for sharing...

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