Hydrotest Question - Closure Weld using a WN flange 3

[Krausen]

A number of my coworkers are in disagreement with my understanding of B31.3 hydrotest requirements for needing to hydrotest every component in a new piping system (with exception of the closure weld). A situation has come up where a new B16.5 WN flange is being used at a tie point where the buttweld of the flange's weld neck will serve as the closure weld to be exempted from hydrotest using 100% RT inspection of the weld. The current plan is to not hydrotest this new B16.5 WN flange before welding it in, leaving the flange face component untested before going into service (since B16.5 flanges are not pressure tested by the manufacturers). My understanding is this WN flange needs to be hydrotested first before welding in the weld neck as the closure weld in order to pressure test the flange face. Curious if the forum's interpretation is in line with mine on this?

 

[RJW000]

I think 1503 is saying the opposite by his first comment. I agree with you Kevin.

 

[1503-44]

There have been proposals to eliminate hydro completely in favor of 100% radiographic tests. Just not sure if thet's going anywhere yet.

What I'm saying is that in this case, especially where it is specifically stated the flange was not tested at the mfgr; and it should have been hydrotested with the rest of the spool. Its an easy fix. No logic exercises necessary. No compliance issues.

Kevin, repair and replacement of original system components is outside the design codes scope. How often do you replace just a flange, rather than an entire spool, which would most likely be hydrotested at the fab shop anyway.

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

 

[1503-44]

23-14 makes no sense. Everything is listed.
I'd understand if it only applied to valves, pumps and some other mfgr items, but as you can see, it can easily be seen as a blanket covering the entire system resulting in no hydro required.

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

 

[r6155]

See:
ASME PCC-2–2018 (2022 edition not yet in my library)
Repair of Pressure Equipment and Piping

Article 301
Replacement of Pressure Components.

Regards

 

[1503-44]

Not only is it practical, its easy if done right the first time.

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

 

[Krausen]

I'm with 1503 on this. But I'm also aware of experienced others (licensed engineers & certified inspectors) who side with RJW000 on this & truly believe the only reason hydrotests are done is to test welds.

It seems their prime justification is simply "cuz that's how we've always done it" without regard to B31.3 code. Although I can see how Interpretation 28-12 & 23-14 (neither of which make sense to me) could lead them to their reasoning, without reading the base B31.3 code.

 

[1503-44]

I'm just an engineer that prefers to follow the codes, at least whenever physically possible. I prefer to figure out how to do that, rather then how work around them. Second guessing them is for the lawyers that will surely do that for you, should worse come to worst. I only want to be on the right side of that equation when the phone rings at 3am.

And I have had failures of mfgr equip that was subject to additional test and inspection, one post inline hydrotest, even at a lower pressure than the factory test. An offshore, undersea valve. Only cost a few million to replace that one, and that was back in the day when a million was a real million; not the chump change of today. Which only goes to show that hydrotesting isn't a magic wand either. Things can still fail after we've done all we can do. I don't think it's an arguemunt to stop hydrotesting. Maybe it needs to be even longer duration, but that's above my pay grade.

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

 

[1503-44]

Not a weld test
The "flange" ONLY means THE flange.

B16.5 Note: 2009 edition

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