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hydrotest, service test or pneumatic test on nitrogen
2

hydrotest, service test or pneumatic test on nitrogen

hydrotest, service test or pneumatic test on nitrogen

(OP)

We usually perfom service test for nitrogen service, sometimes, pressures are 230 psig.

I think it is not correct. How do you interpret B31.3

Thanks,

RE: hydrotest, service test or pneumatic test on nitrogen

vladimir99,

ASME B31.3 would allow service test for services up to 150 psig non-flammable, non toxic services.  The 230 psig nitrogen would be over the pressure allowed for simple service test.  A 1.5X hydrotest or 1.1X pneumatic test would be the code pressure test /leak test requirement.

If the line sizes are small (NPS-2" or NP 50 mm) then it is probably easy to use bottle high pressure nitrogen to test the piping at 1.1X = 255 psig.         

RE: hydrotest, service test or pneumatic test on nitrogen

ApC2Kp,

If B31.3 allows testing by N2 for nonflamable nontoxic services operating to 150 psig and N2 test pressure is 1.1 times op press, why would you ever N2 test to anything more than 1.1 x 150=165 psig?  In that case I believe what Vladimir says is true, that it is unwarrented to test to 230.

http://virtualpipeline.spaces.msn.com

RE: hydrotest, service test or pneumatic test on nitrogen

(OP)
I think it is working pressure not the operating pressure we use for the test.

So 1,1 x work pressure for a pneumatic test (recommended by my inspector)

1.5 x for hydrotest but I need drying the lines before putting in operation. Not good with SW lines.

Service test only service up to 150 psig. (operating or working?)

RE: hydrotest, service test or pneumatic test on nitrogen

Operating or working?  To be precise, neither one.  "Design pressure" should be used to determine test pressure.  

B31.3 doesn't define "working pressure", "service pressure" or "operating pressure" in the context of test pressure.  "Design pressure" is the term used in paragraph 345.5.4 to determine the test pressure.  "Design pressure" is defined in 301.2 as the highest gage pressure to which the piping will be subjected.  That would include all possible operating and other pressures (except for test pressure and some relatively minor transient excursions above the design pressure from time to time).

345.5 Pneumatic Leak Test

Quote:


345.5.4 Test Pressure
The test pressure shall be 110% of design pressure.

http://virtualpipeline.spaces.msn.com

RE: hydrotest, service test or pneumatic test on nitrogen

Catagory D only requires an initial service leak test where the test pressure equals opering pressure.  

Normal Fluid Leak test can be tested at 110% of design pressure with a gas or 150% of design with a liquid.

RE: hydrotest, service test or pneumatic test on nitrogen

(OP)
is nitrogen a category D service ?

RE: hydrotest, service test or pneumatic test on nitrogen

as long as the pressure is under 150 psig, N2 is catagory D, IMHO.

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