Hi,

In Section VIII DIv. 2 Table 7.2 specifies "RT or UT" for longitudinal welds in a vessel shell.

Paragraph 7.5.5. is applicable to "UT in lieu of RT". My opinion is that this paragraph iS NOT applicable to just the UT per Table 7.2, as UT is an equal opportunity in the table.
Can anybody support my opinion?

DK

I agree with your interpretation mainly because of Table 7.5 which defines (and separates) the technique, method, and acceptance criteria for Ultrasonic Examination (when used in lieu of RT) from the others.

The Ultrasonic Examination (when used in lieu of RT) is classified as a separate technique in Table 7.5 and also defines separate acceptance criteria.

_________________
A question properly stated is a question half solved.

Thanks, Jim,
you will see the question now:

When there is an ordinary Butt weld in a P-No. 1 vessel shell long seam, and the manufacturer choses to use UT, this is perfectly okay according to table 7.2.
In my reading this would NOT BE UT IN LIEU OF RT. Would you agree?

(remembering the good old Case 2235-x, the requirements for UT are a bit tougher than only Article 4 of Section V, this puzzled me when reading 7.5)
Surprisingly there is no interpretation yet in this question.

Remaining question: I could not find any meaning of UT in lieu of RT, like where is it used, could you?

Dk

Yes I agree.
I will do some research on this from my end and if either one of us come up with a clear definition, we can post a reply here in this thread.
This is a good question.
There must be a case where one would use "UT in lieu of RT" otherwise, why provide acceptance criteria?

_________________
A question properly stated is a question half solved.

What I have found is the following:

Just as Table 7.2 specifies the type of NDE required for welded joints, so does Tables 7.3 and 7.4. When Table 7.3 or Table 7.4 is specified in the text of VIII-2, you must follow the method of NDE applicable.

As an example: if Table 7.3 (Selection of Nondestructive Testing Method For Full Penetration Joints) is specified within the text of VIII-2, this Table then defines the method of NDE applicable by :
1) type of joint
2) shell thickness
NOTE:In one case presented in Table 7.3, RT is exclusively required for types 1, 2 and 3 joints less than 1/2 inch (13mm)

Thus the normal method would be to perform RT, however,you may choose to perform "UT in lieu of RT" (for whatever reason) which is different than that specified in Table 7.3. Now, I believe you would fall under Paragraph 7.5 defining the acceptance criteria for "UT in lieu of RT" if performing UT when RT is clearly specified.

_________________
A question properly stated is a question half solved.

Dr Koelbl,

"Remaining question: I could not find any meaning of UT in lieu of RT, like where is it used, could you?"

I do not have access to Div 2 but is this clause from Div 1 similar to anything in Div 2 ?

(7) ultrasonic examination in accordance with UW-
53 may be substituted for radiography for the final
closure seam of a pressure vessel if the construction
of the vessel does not permit interpretable radiographs
in accordance with Code requirements. The absence of
suitable radiographic equipment shall not be justification
for such substitution.

Regards,
BB

To my understanding, sequence of selecting RT or UT goes as below;

1. Section 7.4.4: Selection of examination method for internal flaw- Select from table 7.3 whether RT is applicable and/ or UT is also permitted.

2. Section 7.4.3: Extent of Non Destructive Examination- Extent of examination is selected from table 7.2 (either for RT or UT) for the type of examination method selected from table 7.3 in step 1.

With the above sequence UT as per 7.5.5 is permitted in lieu of RT for T>13 mm for type 1,2 & 3 joints. For t < 13 mm & joint types 1, 2 & 3 UT in lieu of RT is not permitted (except for final closure seam where interpretable radiographs are not possible).

Please correct me if I am wrong in my interpretation.

Regards

BB... I performed a search on the VIII-2 for the terms "closing seam" and nothing came up. I am not aware of anything like VIII-1 in VIII-2.

Here is a link to the content provided in Chapter 22 of the ASME Companion Guide 3rd Edition. This content is a total replacement of the content provided in Chapter 22 of 2nd Edition of the ASME Companion Guide. With the 2010 Edition of VIII-2 now published, I think the paragraph references in Chap 22 of the Guide below may be outdated. But, you may search at your leisure.

http://www.krrao.com/images/Rao_Book_Chap22_v6_Final_1-11-08_2-27-08_PASTOR_COMMENTS_4-2-08_4-7-08.doc

In paragraph 7.5 the following exist in VIII-2:
7.5.1 General
7.5.2 Visual Examination
7.5.3 Radiographic Examination
7.5.4 Ultrasonic Examination
7.5.5 Ultrasonic Examination Used in Lieu of Radiographic Examination
7.5.6 Magnetic Particle Examination (MT)
7.5.7 Liquid Penetrant Examination (PT)
7.5.8 Eddy Current Surface Examination Procedure Requirements (ET)
7.5.9 Evaluation and Retest for Partial Examination

I still come to the conclusion that UT can be selected in it's entirety except when RT is exclusively mentioned as the volumetric method within the text of VIII-2. Only then can one use the "UT in lieu of RT" method and acceptance criteria specified in Table 7.5

_________________
A question properly stated is a question half solved.

Hi Jackal,
Not sure if it is still applicable because I only have ASME VIII Div 2 2001 (I do not work on pressure vessels) but after a bit of digging I found the exact statement in Div 2 that I have posted above from Div 1,
Table AF 241.1 Note (2)
Regards,
BB

I would like to make a correction after reading ASME PTB-1-2009.

The following is taken from PTB-1-2009 ASME Section VIII - Division 2 Criteria and Commentary Date of Issuance: June 10, 2009 found here: http://catalog.asme.org/Codes/PrintBook/PTB1_2009_Section_VIII.cfm

7.5.4 Ultrasonic Examination
Part 7, paragraph 7.5.4 covers ultrasonic examination. This paragraph is unchanged from Article 9-3 of the old VIII- 2 or VIII-1, Appendix 12. The only addition of note is the requirement that flaw evaluations shall only be performed by UT Level II or III personnel.

7.5.5 Ultrasonic Examination Used in Lieu of Radiographic Examination
Part 7, paragraph 7.5.5 covers ultrasonic examination when used in lieu of radiography to satisfy the requirements for obtaining the joint efficiency from Table 7.2. This paragraph represents the incorporation of Code Case 2235, which was first approved in 1996 and has undergone several revisions since that time.

The statements above come directly from PTB-1-2009 and show that paragraph 7.5.5 applies instead of 7.5.4 when determining the joint efficiency specified in Table 7.2. This is because paragraph 7.5.5 incorporates Code Case 2235 whereas paragraph 7.5.4 does not.

So, after reading this, I now understand how Table 7.2 can be misleading. The reference to “RT or UT” specified in Table 7.2 requires applying paragraph 7.5.5 requirements and not paragraph 7.5.4. I highly recommend getting ASME PTB-1-2009 if you are going to perform VIII-2 Code Construction.

Does everyone agree? BB?, Dr.? Sanjeev?

_________________
A question properly stated is a question half solved.

According to colleagues within my organization, Sanjeev had the correct answer.

Although not clearly written into Table 7.2 or the paragraphs referring the user to Table 7.2, this sort of get addressed in paragraph 7.4.4 which addresses the selection of internal flaws(volumetric examination) techniques.
Coming to this conclusion was not that simple. At first glance, I took 7.4.4 to be a paragraph describing how to locate (known) internal flaws and not the paragraph that selects the volumetric method (UT or RT) when determining the joint efficiency.

Paragraph 7.4.4 refers to Table 7.3 which clearly states whether RT or UT is permitted depending on thickness and which paragraph to use.

_________________
A question properly stated is a question half solved.