What are the Essential Drawings for Piping and Mechanical Engineers?

[amnoorulaman]

Dear Engineers,

I am Noorul Aman. I am a mechanical engineer in the field of PIPING AND CONST/ARCI.
Here I want to shear whatever I gather the information about engineering field with you.

Piping/Mechanical Design Drawings
GENERAL
The primary drawings that a Piping/Mechanical Field Engineer will use in the course of completing
a field assignment are:
· Piping and Instrument Diagram (P&ID)
· Piping Isometric
· Plot Plans
· Piping Class Sheets
· Piping Support Details and Hanger Drawings
· Vendor Drawings and Manuals
· Instrument and Tubing Drawings
· Standard Instrument Details
· Steam Heat Tracing Drawings
These drawings along with project installation specifications provide quality guidelines for properly
completing the assigned system.

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[amnoorulaman]

Piping and Instrument Diagram

The single most important drawing for the installation of piping systems is the Piping and
Instrument Diagram (P&ID). It provides the base design description of the required pipe routing
and sizing, flow direction and slope, instrumentation and controls, insulation, heat tracing, and
equipment and/or instrument references. This provides a road map to finding other drawings,
vendor data, and piping information to properly complete the installation. The P&ID does not
however provide dimensional data or physical locations of any commodities.
The Piping Line List and the Instrument Index are issued documents which often provide this
information.

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pipingguide.blogspot.com

 

[amnoorulaman]

What is the ASME code followed for design of piping systems in Process
pipings (Refineries & Chemical Industries)?
(i) B31.1
(ii) B31.3
(iii) B31.5
(iv) B31.9
Answer (ii)

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pipingguide.blogspot.com

 

[amnoorulaman]

What do you mean by following items?
i. )ISLB-400 ii) ISMB-600 iii) ISHB-350 iv) ISMC-300 v) ISJB-150 vi) ISLB-200
vii)ISMB-450 viii)ISWB-400 ix) ISJC-200 x) ISLC-350 xii) ISMC-250
Answer:
i. Indian STD light weight beam, Web size – 400
ii. Indian STD medium weight beam, Web size – 600
iii. Indian STD ‘H’ beam, Web size – 350
iv. Indian STD medium weight channel, Web size –300
v. Indian STD junior beam, Web size – 150
vi. Indian STD light weight beam, Web size – 200
vii. Indian STD medium weight beam, Web size – 450
viii. Indian STD wide flange beam, Web size – 400
ix. Indian STD junior channel, Web size – 200
x. Indian STD light weight channel, Web size – 350
xi. Indian STD medium weight channel, Web size – 250

cont...
pipingguide.blogspot.com

 

[amnoorulaman]

What is this item?
i. ISA-100X100X12 ii) ISA-80X50X10 iii)ISLT-100X100
Answer:
i. Equal angle size 100x12 THK
ii. Unequal angle size 80x50x10 THK
iii. Indian STD light weight tee bar size 100x100

 

[amnoorulaman]

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.

 

[amnoorulaman]

From which size onwards NB of pipe is equal to OD of Pipe?
Ans: From the size 14” and onwards NB = OD of pipe.

 

[amnoorulaman]

Write down the outside diameter of following pipe?
i. 3 inch ii) 6 inch iii) 10 inch iv) 14 inch
Answer:
i. 3 inch = 88.9mm ii)6 inch = 168.28mm
iii) 10 inch = 273.06mm iv) 14 inch = 355 mm(OD= Size X 25.4)

 

[amnoorulaman]

What is the difference between machine bolt and stud bolt?
Answer:
Machine bolt has a head on one side and nut on other side but stud bolt have nuts on
both sides.

 

[amnoorulaman]

While welding of pipe trunion to pipe/reinforcement pad you have to put a hole
or leave some portion of welding why?
Answer:
For venting of hot gas which may get generated due to welding

 

[amnoorulaman]

What do you mean by following type of welding?
i. SMAW ii)TIG
Answer:
ii. SMAW = SHIELDED METAL ARC WELDING
iii. TIG = TUNGSTEN INTER GAS WELDING

 

[amnoorulaman]

What should be the radius of long radius elbow?
Answer:
1.5D (Where “D” is the diameter of the pipe)
14. Normally where do we use the following?
i. Eccentric reducers ii)Concentric reducers
Answer:
i. Eccentric reducers = Pump suction to avoid Cavitation, To maintain elevation (BOP) in
rack.
ii. Concentric reducers = Pump discharge, vertical pipeline etc.

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pipingguide.blogspot.com
papermillpiping.blogspot.com

 

[amnoorulaman]

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

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cont...
pipingguide.blogspot.com
papermillpiping.blogspot.com

 

[amnoorulaman]

What do you mean by Cavitation in Pump?
A pump is designed to handle liquid, not vapour. Vapour forms if the pressure in the
pump falls below the liquid’s vapour pressure . The vapour pressure occurs right at the
impeller inlet where a sharp pressure drop occurs. The impeller rapidly builds up the
pressure which collapses vapour bubbles causing cavitation and damage . This is
avoided by maintaining sufficient NPSH.
(Cavitation implies cavities or holes in the fluid we are pumping. These holes can also
be described as bubbles, so cavitation is really about the formation of bubbles and their
collapse. Bubbles form when ever liquid boils. It can be avoided by providing sufficient
NPSH.)

 

[amnoorulaman]

What do you mean by NPSH? How do you calculate it?
NPSH: Net Positive Suction Head. NPSH is the pressure available at the pump suction
after vapour pressure is substarcted.
It is calculated as : Static head + surface pressure head - the vapor pressure of your
product - the friction losses in the piping, valves and fittings.
It thus reflects the amount of head loss that the pump can sustain internally before
vapour pressure is reached.

cont...
pipingguide.blogspot.com
papermillpiping.blogspot.com

 

[amnoorulaman]

What is the ASTM code for the following?
i. CS pipe ii) CS fittings iii)CS flanges iv)AS pipe P5/P11 v)Cast CS Valves
Answer:
i. CS pipe = A106 Gr.B
ii. CS fittings = A234 Gr.WPB/WPBW
iii. CS flanges = A105
iv. AS pipe = A335 Gr P1/P11
v. Cast CS Valves = A216 Gr.WCB

 

[selsat2000]

Dear Engineers,

I am selva. I am a mechanical engineer in the field of PIPING AND CONST/ARCI.
Here I want to shear whatever I gather the information about engineering field with you.

Piping/Mechanical Design Drawings
GENERAL
The primary drawings that a Piping/Mechanical Field Engineer will use in the course of completing
a field assignment are:
· Piping and Instrument Diagram (P&ID)
· Piping Isometric
· Plot Plans
· Piping Class Sheets
· Piping Support Details and Hanger Drawings
· Vendor Drawings and Manuals
· Instrument and Tubing Drawings
· Standard Instrument Details
· Steam Heat Tracing Drawings
These drawings along with project installation specifications provide quality guidelines for properly
completing the assigned system.

----------- cont.

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