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Hydroststic pressure 1

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Green white

Mechanical
Jul 7, 2022
13
I have a pipeline with a design pressure of 1200 psi, and a pressure rating of #600
According to ASME B 31.4, the hydrostatic test pressure for a pipeline is 1.25 times the internal design pressure at that point. Could anyone advise which case of the following is correct for the hydrostatic test pressure of the pipeline
Case 1
The design pressure is 1200 psi
Therefore, (hydrostatic pressure test shall be 1.25 X 1200 psi = 1500 psi)
Case 2
The rating of the pipeline is #600 (design pressure of 1440 psi)
Therefore, the hydrostatic pressure test shall be 1.25 X 1440 psi = 1800 psi
 
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The test pressures of both cases are acceptable, the differences are,
1. The pipeline may be operated only up to the design pressure, I.e. 1200 psi.
2. The pipeline can be operated up to full rating of the 600# Class pressure limit, i.e. 1440 psi. It’s more flexible in operation without adding any change or cost.
 
If your design pressure is 1200 psig, case 2 is incorrect. No need to test to 1.25 x 1460 psig (it is not 1440).

Your "pressure rating" is not ANSI 600#. Maybe you are using 600# flanges.

Pressure rating is the lowest operating pressure of anything making up the system. It may be your pipe or fittings. You do not tell us those details.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
There is no such thing as a pipeline "rating".

Pipelines are designed to a design pressure which is very often/usually below the MOP of a flange so that you don't over design your pipeline.

If your pipe is properly designed (i.e. designed to 1200 psi) then testing to 1800 psi could result in yielded pipe.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
sorry
pipe fittings and valves are ANSI 600
MOP of 1440 psig for this pipeline
Therefore, the hydrostatic pressure test shall be 1.25 X 1440 psi = 1800 psi

pipeline design pressure is 1200 psi
Therefore, (hydrostatic pressure test shall be 1.25 X 1200 psi = 1500 psi)
 
OP,
What do you intent to do? Do a hydrotest on the pipeline with the valves and fitting as one system? if that is the case, you will follow the Code rule of B31.4 as 1.25 x Design Pressure.
When flanged valves (API 6D), flanges (MSS-SP-44/ASME B16.47) and likewise fittings are used, those are ANSI Class rated and shop tested to 1.5 x CWP but when you use these valves and flanges in the string, the pipeline hydrotest is dictated by the B31.4 rule.

GDD
Canada
 
Green White,

Yet again NO.

You cannot have MOP higher than the Internal Design Pressure.

Your flanges and fitting are ASME class 600 and need to be rated the same or higher than your pipeline internal design pressure, but they have no relevance to the pipeline test pressure.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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