B31.3 Radiography Examination

[Kajtek08]

Hi,

I'm hoping someone can help me clarify the B31.3 radiography examination requirements.

As per B31.3 “Not less than 5% of circumferential butt and
miter groove welds shall be examined fully by random
radiography”

If a after a hydro 5% of the welds need to be radiographed. When you have few welded joints to test, does the 5% applies to the number of welded joints or to the total length welded?

If it’s to the number of welded joints, if I have total of 3 welds does that mean I have to test at least one full weld?

Thanks,
Andrew

 

[JohnGP]

Andrew,
I take "shall be examined fully" as stated in B31.3 to mean the complete circumferential weld. Also "not less than 5%" can obviously be more than that - even 33% in your described situation. So yes, I believe you should be testing at least one full weld.

I am a bit puzzled though by the bit about radiography after hydro. Radiography and any other NDE is meant to confirm integrity of welds prior to hydrotest, and hopefully highlight if any repair is required. I thought maybe a "golden weld" situation, as then you could have radiography after hydro, but can't be the case as that weld needs to be fully radiographed anyway, so the original question would not have been necessary.
Cheers,
John

 

[DekDee]

Andrew,
I agree with Johns response.
The other thing to consider is how many welders ?
1 welder x 3 joints or 3 welders x 1 joint ?
Your inspection must cover all the welders so if 3 x welders you will have to RT 3 x joints.
Cheers,
DD