Hydrostatic test pressure calculation for Process Piping per ASME B31.3

[cjabhijit]

Dear All,

Could you pls guide me to calculate Hydrostatic Test Pressure for below line?
Actually I need to put the calculated test pressure value in the line list.

Line service-Process Liquid (Crude from wellhead)
Test medium-Water
Spec-CS #900 piping
Line size-4"
Operating Press=18.7 kg/cm2
Operating Temp=150
Design Press=92 kg/cm2
Design temp=325 deg C
job site-Kuwait

How to calculate Test pressure for the above line & what else I need to calculate the same?

Pls help



Thanks & Regards,
Abhijit

 

[racookpe1978]

Are you really sure you have a ASME 31.3 specification condition?

Crude oil from a wellhead is oil and gas, cross-country, pipeline service conditions, not general process industry inside a plant.

" ASME B31.3 contains requirements for piping typically found in petroleum refineries; chemical, pharmaceutical, textile, paper, semiconductor, and cryogenic plants; and related processing plants and terminals. ... It serves as a companion to ASME’s B31.1"

 

[BigInch]

Fire temp spec for Iraq attack.

Technology is stealing American jobs. Stop H1-Bs for robots.

 

[cjabhijit]

Yes racookpe1978, I have confirmed & it is B31.3 itself.

Can anybody pls revert what is the procedure to calculate Test pressure?

What I understood is for

Water as per test medium, test pressure should be 1.5 X Design Pressure
For Air (Pneumatic) as test medium, test pressure should be 1.1 X Design Pressure.

However, there are certain correction factors based on the spec & B31.3 which I am not clear upon hence need your feedback to about it in a right way.


Thanks & Regards,
Abhijit

 

[XL83NL]

Refer to B31.3 para 345.1, specifically 345.4.2 for the test pressure. From there on you need to be able to solve this on your own.

 

[LittleInch]

Abhijit,

You need to get a copy of ASME B 31.3, latest edition is 2014.

Section 345.4.2 tells you what you need to know.
PT p 1.5 PST/S (24)
where
P = internal design gage pressure
PT = minimum test gage pressure
S = allowable stress at component design temperature
for the prevalent pipe material; see
Table A-1
ST = allowable stress at test temperature for the
prevalent pipe material; see Table A-1

Hence in your case you need to know what the St value is for your material at the design temperature (325C) compared to whatever temperature your test is going to be at (30c?)

Then multiply that factor ( which is >1) x 1.5 x your design pressure and you have your test pressure.


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