NDT performed after or before Hydrotest test

[mrmalcolm]

Dear colleagues,
Any code mentioned Non-destructive testing should be performed after or before the hydrostatic test?
If non-destructive testing is performed after the hydrostatic test, is it possible that the hydrostatic test could cause minor imperfection to expand into major defects?
If non-destructive testing is performed before the hydrostatic test, could the pressure of the hydrostatic test cause the pressure vessel to explode?
Thank you.

 

[JStephen]

Normal non-destructive testing wouldn't weaken or damage the part being tested, which is what your question seems to assume.
Just exactly what kind of non-destructive testing are you referring to?

 

[mfgenggear]

OP
Hydrostatic test with water will not explode.
I prefer to ndt before

 

[IdanPV]

Per ASME VIII-1 - UG-99(a)(2):

All examinations have been performed, except those required after the test

Per B31.1 - 137.1.5:

Pressure testing shall be performed following the completion of postweld heat treatment required by para. 132, nondestructive examinations required by Table 136.4.1-1, and all other fabrication, assembly, and erection activities...

 

[mfgenggear]

Here is the issue. Radio graphic inspection , penetrant inspection, or magnetic inspection will find imperfections. Depending on manufacturing and material. And what is specified on the drawing or quality contract requirement. If rework or repairs are required.
It must be performed prior to hydrostatic pressure testing.
Once these ndt procedures pass. Then hydrostatic test.
.

 

[mrmalcolm]

Thank you, colleagues. So,could pressure testing cause minor imperfection to become defects?

 

[mfgenggear]

Thank you, colleagues. So,could pressure testing cause minor imperfection to become defects?

Generally it's pass or catastrophic failure

 

[r6155]

What is minor imperfection?

 

[mfgenggear]

What is minor imperfection?

I should have said unacceptable indications.
Eg cracks, porosity ect

 

[r6155]

@ mfgenggear​

You're wrong and very confused.
You need to read more.
I'm sorry.

 

[mfgenggear]

@ mfgenggear​

You're wrong and very confused.
You need to read more.
I'm sorry.

Your answer is ridicules and has no merit.
It applicable to the contract, contract requirements , the specifications, and your insulting answer is un Profesional.

 

[EdStainless]

NDT (all methods) detects indications.
Whether or not these are of concern depends on your standards.
Verifying what these indications are requires some destructive examination.
We always did NDT prior to Hydro. for a couple of reasons.
1. Much easier to repair things while they are dry
2. To tell us if we need to do more inspection/testing before carrying on.

 

[r6155]

good luck.