Strength Testing Alternative

[VigilanteB]

Section 345 in ASME B31.3 appears to allow the substitution of a 1.5 hydrostatic strength test by a 1.1 pneumatic test if the "hydro" is deemed impracticable. Assistance is required on the interpretation of this section. I have a system that would require a hydrotest of 150barg and would contain around 60Te of water (deem impracticable) and would like to subsitute this with a 110barg N2/He test.

 

[codeeng]

We generally permit pneumatic testing of piping systems when properly justified. Stored energy should be less than 2.7 x 10^7 J. If your piping system requires registration then you should also have your procedure approved by your AI.

 

[VigilanteB]

Thanks codeeng, not clear from the original posting but this request refers to a previous system that would like to be re-rated from 90barg to 100barg. The original hydrotest was 135barg allowing the 90barg design pressure, so what is gained by carrying out a 110barg pneumatic test over the original hydrotest.

 

[codeeng]

This could be justification for doing nothing. If you mean 60 tonnes of water the test energy is 66 x 10^7 J which is very high. Perhaps a thorough inspection of the system may suffice.

 

[PAN]

codeeng,
Please advise me how to convert 60 tonnes of water to 66 x 10^7 J. Thanks in advance.