Minimum test pressure requirement and duration if gas medium is used (for pre installation test)

[ceenote]

Hi,

What is the minimum test pressure requirement and duration(for transmission pipe) in class 3 location if gas is the test medium? This is for pre-installation test of short pipe.
Thanks

 

[LittleInch]

I don't think there are any requirements listed for a pre installation test, but normally the idea is that you've tested the pipe to at least the same pressure it well see in a hydrotest. How long? A mill test is sometimes a short as 10 seconds so anything longer than that would be better.....

Yourr question is a bit vague so that's the best I can offer at the moment.

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

 

[ceenote]

Thanks. I spoke to another engineer here at my work place. Again, Thanks

 

[bimr]

Pneumatic pressure testing of pipelines refers to the use of air or inert gas (such as nitrogen) as a test medium instead of water. Pipeline operators rarely use pneumatic pressure testing for systems that operate at pressures above 100 psig due to safety concerns. The amount of energy stored in a compressed gas greatly exceeds the energy stored in a compressed liquid. If a failure of the pipeline were to occur during a high-pressure pneumatic pressure test, the sudden release of this large amount of energy could be dangerous to personnel conducting the tests.

http://www.wermac.org/others/ndt_pressure_testing.html

The recommended practice is that a QC inspector will walk through the whole piping system and check for leaks. Every single length of piping, welds, bolted connections shall be visually examined for any leakage. Duration of this activity varies with the span of piping system.

 

[ceenote]

Thanks

 

[BigInch]

B31.8 =2h. B31.4=4hr for strength testing.
B31.4 requires hydrotest (with water, or low Vp hydrocarbon).

You should keep pressure below the max allowed for gas test mediums.