Exemption for Re-hydro Test in PWHT U-stamped Vessel

As per ASME Code, VIII, Div.1, Para. UG-100 Pneumatic Test, a pneumatic test may be used in lieu of the standard hydrostatic test as described in UG-99 for vessels only when:

1. that are so designed and/or supported that they cannot safely be filled with water;

2. not readily dried, that are to be used in services where traces of the testing liquid cannot be tolerated and the parts of which have, where possible, been previously tested by hydrostatic pressure to the pressure required in UG-99.

Those the only executions, and therefore, I think you have to repeat the hydrostatic test.

Hello hari.k,

Good answer from Abdel!

You could also check some of these sites out, some of which deal with the request you ask, that is welded parts inside a pressure vessel?

http://www.google.com/search?hl=en&client=safari&rls=en-gb&ei=raRgSufkOtCfjAeajai9Dg&sa=X&oi=spell&resnum=1&ct=result&cd=1&q=the+code+details+for+excluding+re-hydro+test+to+weld+a+presure+or+non+pressure+parts+in+side+the+vessele+after+PWHT+%26+Hydro+test+completed+under+ASME+Section+VIII+Division+1&spell=1