pressure test of pipeline

[mechmaj]

Hi,
Is that any reference about testing the pipeline by air instead of hydrostatic test.
Regards,

 

[BigInch]

What code?

example B31.4 states,

437.4.3

Leak Testing. A 1 hr hydrostatic or pneumatic
leak test may be used for piping systems to be
operated at a hoop stress of 20% or less of the specified
minimum yield strength of the pipe. The hydrostatic
test pressure shall be not less than 1.25 times the internal
design pressure. The pneumatic test gage pressure shall
be 100 psi (7 bar) or that pressure which would produce
a nominal hoop stress of 25% of the specified minimum
yield strength of the pipe, whichever is less.

However B31.8 states,

841.322

Pipelines located in Location Class 1, Division 2 shall be tested either with air or gas to 1.1 times the maximum operating pressure or hydrostatically to at least 1.1 times the maximum operating pressure if the maximum operating pressure is 72% SMYS or less.

Don't recall if API 1110 mentions air or not, you can check that one.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[zdas04]

There's a document on my web page that discusses some of the subtleties of gas vs. liquid tests. It might help you understand the issues a little better.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

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