Hydrostatic Pressure Testing

[TzPetro]

I have gas line that was designed at 19000kPa and Operating pressure was 16600kPa. It was hydro tested at operating pressure x1.25. Now I need to do some repairs on the section of this line (cut and weld new spool). The current operating pressure is 11000kPa. Which pressure will I use after repairs for hydrotesting the line? Old operating pressure or the current one? Your views will be appreciated.

 

[1503-44]

The design pressure should be used to determine test pressure.

Use of a lower pressure would force the replaced segment to be derated.

 

[LittleInch]

What's your design code?

If it's b31.8 the test pressure sets your MAOP.

You won't be able to exceed that pressure so if that's good for you then yes you can test to a lower pressure which derates the whole line.

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