Use of UT in place of RT

[dbday]

Hi,
Can anyone tell me if ASME VIII Div 1 allows use of UT in place of RT without reference to the client.
I am aware of code case 2235 and its requirements, but was wondering if there was anything specific within the code itself other than this ?
Thanks for any help.

 

[ak1965]

Lets go by basics of NDT....UT can not be complimentary to RT...as the orientation of defects, that can be found out are normally at 90 degrees apart in each case.....!

So think twice replacing RT with UT...However, if at all the replcament is inevitable, TOFD in place of UT would be a betetr choice.

 

[CodeRef]

Your questions lacks detail and specific application. There is not a blanket condition in VIII-1 that allows UT in lieu of RT for all references to RT.

See Non-Mandatory Appendix L pargraph below for one such case........
L-1.2 Requirements for Radiography
Radiography is mandatory for certain vessel services
and material thicknesses (UW-11). When radiography is
not mandatory, the degree of radiography is optional, and
the amount of radiography must be determined by the user
or his designated agent (U-2).

Of course, doing something other than what the client expects or doing something without authorization, and lack of clarity is dangerous in any business.



FAQ731-376

 

[dbday]

The specifics are;
Vessel approx 150m3 volume, carbon steel A516-70, DP 10 Bar, nominal diameter 3500mm. Joint efficiency assumed in thickness calcs is 1.0 hence original requirement to use RT, but supplier wants UT as cost and programme are better.
Vessel may be full of water at ambient temperatures, otherwise will be 50/50 air / water.

 

[rustbuster]

Phased Array per code case 2235 is likely your best approach

 

[CodeRef]

So, you are asking if you can perform UT in lieu of RT to satisfy UW-11 Joint Efficiency requirements ............ without asking the client if it is okay ......

I would run this by your AI and see what he can find. Thats whay he is there. I would not be comfortable answering your question directly as I am not privy to all of the other design criteeria...I would have to conduct a thorough check, As should your AI and yourself. I believe you have a good start by addressing CC-2235.
However, I would recommend informing the client and receive their concurrence.

FAQ731-376

 

[dbday]

Job is not a 'U' stamp job so we have no formal AI involvement. Our client merely says to tell them where in the code it says you can use UT and they will be happy !!
Our supplier says they can't comply with all of CC2235 but has offered a procedure that is backed by the independent third party, not AI qualified people, so not sure that their backing adds any real wieght to the proposition, which is why I am asking the question.

 

[CodeRef]

Okay, I understand. Thanks for helping me along. I spent a little time looking at CC-2235-6. Code Case 2235 permits the use of UT in lieu of RT at any time, under the qualifying conditions of the Code Case. In other words, the Case allows for the substitution of ultrasonic examination in lieu of radiographic examination for all welded seams in a vessel that require examination.

Does this same requirement exist in the current Code? i.e. 2008 Edition. No it does not. Maybe someday it will. Sometimes Code Cases become adopted and incorporated into the applicable Code based upon committee vote....This particular Case is still a Code Case, and you will not find words in the current Code to support the same, Thus the reason it is a Code Case (alternative) to the Code.

Hope this helps you!

FAQ731-376

 

[stanweld]

Code Case 2235-9 is applicable today until it is rescinded or incorporated into the Code for Code stamperd vessels.

Since the vessel is not U-stamped, the Owner's approval is required to use UT not in accordance with the Code Case. If the Owner is happy with UT as permitted before adoption of the Code Case, present that to the Owner.

 

[CodeRef]

Good Point Stan, I'll add this....The Foreword of the Code addresses the use of Code Cases, stating:

"Manufacturer's and users of components are cautioned against making use of revisions and Cases that are less restrictive than former requirements, without having the assurance that they have been accepted by the proper authorities in the jurisdiction where the component is to be installed."

Not all jurisdictions automatically accept Code Cases and some jurisdictions are opposed to certain Code Cases. The manufacturer should verify acceptance by the appropriate parties before using any Code Case.

FAQ731-376

 

[CodeRef]

FYI....A correction to my last post.....I just checked the current VIII-1 (2008 Addenda)for the words I quoted above... This particular wording was editorially revised (removed) from the forward of the Code (VIII-1) in 2004, But I believe the intent remains....Any other opinions?

FAQ731-376

 

[metengr]

Correct because the Foreward of the Code is actually not part of the ASME Code itself. This has been discussed in previous Code meetings resulting in the changes as mentioned.

More changes to come.... possible elimination of the addendum publishing cycle and going to a 2 or 3 year hard binder publication cycle.