B31.3 100% Visual Weld Examination. 1

[BlueCat1]

Looking for any advice on the 100% VT requirements for B31.3 Normal Fluid Service. I know it used to be only 5% and in recent years it has been increased to 100%. My questions is this. I work for a very large mechanical contractor that primarily fabricates and installs process piping systems. We work all across the USA and most of what we do is B31.3 NFS. Our manpower is in the mid hundreds. How does ASME expect for 100% of our welds to be visually examined without hiring an army of welding inspectors?

Any insight would be appreciated.

Thanks,
BD

 

[1503-44]

Subcontract welding inspection. Preferably that should be done independently by the owner to ensure unbiased inspection, however that is often not practical.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[XL83NL]

I’m looking if I can find some background on this. Didn’t the code updates in the past also used to have the record number referenced by each change in the SUMMARY OF CHANGES page? That would help a lot

Huub
- You never get what you expect, you only get what you inspect.

 

[DekDee]

XL83NL,
I remember being involved with this discussion / decision.
It was my personal opinion that 100% VT should always have been performed - even if the code only mandated 5% minimum requirement.
Volumetric examination (UT/RT) is supposedly random examination. (5% for NFS)
How can you radiograph a weld if it has not been visually inspected ?
If you visually inspect 5 x welds (out of 100) and RT the same 5 x welds is that classed as "random examination" ?
What about the other 95 x welds ?
VT 100% and if acceptable any 5 of those 100 x joints can be selected for volumetric examination.
Will try and find the background info,
Cheers,
Shane

 

[DekDee]

Hub,
TN 14-628
Cheers,
Shane

 

[XL83NL]

Thanks Shane, found it. Basically, the last line of the TN wraps ut why this Code change was proposed:

Currently 95% of normal service welds may contain potential defects that could cause failures, unless engineering design requires additional NDE examination. 100% visual examination of completed welds is an inexpensive way to help eliminate a good percentage of these potential failures.

Huub
- You never get what you expect, you only get what you inspect.

 

[XL83NL]

Well, bluecat. We’d be curious to hear what you think of all this.

Huub
- You never get what you expect, you only get what you inspect.