ASME B.31.3 doubt

[jalvarez]

Hi, mates:
In the paragraph M341.4 (b)(1) it appears:
"The random radiography/ultrasonic examination requirement of para. 341.4.1(b)(1) apply except that at least 20% of circumferential butt and miter welds and of fabricated lap and branch connection welds comparable to those shown in Figs. 328.5.4E and 328.5.5 sketches (d) and (e) shall be examined"
The doubt: this means that the 20% applies to circumferential butt welds and also to circumferential miter welds or (another interpretation) this is a manner to refer exclusively to miter welds, and the butt welds in the case of straight pipe are excluded of the 20%?
Regards...

 

[metengr]

According to my 2004 Edition of B31.3, Paragraph 341.4 (b) 1
refers to "other examination" as the title

it goes on to state that not less than 5% of circumferential butt and miter groove welds shall be examined fully by random radiography in accordance with paragraph 344.5 or by random ultrasonic examination in accordance with paragraph 344.6. The next two sentences are important.... The welds to be examined shall be selected to ensure that the work product of each welder or welding operator doing the production welding is included. They shall also be selected to maximize coverage of intersections with longitudinal joints.

In paragraph 344.5 the word "random" refers to only butt and miter groove welds

 

[codeeng]

As I read it you add up all the circ welds and miter welds and apply 20% random examination of the total.

 

[jalvarez]

meteng and all, I'm speaking about M341.4(b)(1)
Regards

 

[metengr]

Ok. I reviewed M341.4.(b) 1, Chapter VIII, Part 10. It still kicks you back to Paragraph 341.4 (b)1 except instead of 5% the percentage changes to 20%, and it is also inclusive of fabricated lap and branch connection welds. The reason for being more restrictive by the increased percent sampling is due to Category M fluid services. You need to read both 341.4.(b) 1 and M341.4.(b) 1; the added percentage from 5% to 20% is the total applicable welds with added requirements per 341.4 (b) 1.

 

[jalvarez]

Yes, I'm referring to a fluid that is M category. Conclusion: all kind of welds for M category must be 20% X-rayed... there is no type to be examined at 5%. Or is there one that I don't see?? I recognize that English is not my laguage, but... I think this is confusing.
Thanks to all!

 

[metengr]

The 5% in my first post was taken directly out of B31.3 and refers to the total of both miter groove welds and circumferential welds for normal fluid service. For example, I have a total of 100 butt and miter groove welds, I need to inspect 5 and they need to be from different welders or welding operators.

Now, we move on to Category M fluid service that instead requires a 20% sampling of butt, miter groove, lap and branch connection welds instead of 5%. For example, you have a total of 100 welds in the pipe line, 20 need to be examined. Also, the 20 welds should be selected from different welders or welding operators.

 

[JohnBreen]

jalvarez,

I concur with metengr.

I know I am "nit-picking" but please realize that there is no such thing as category "M" fluid. It is not the fluid that is category "M" but the fluid service (the system) that is category "M" (by the direction of the owner - who has hopfully read Appendix M). Note that the Code considers many hazardous fluid services to be Normal Fluid Service. For example, the Code stipulates that the fluid contained by the category "M" fluid service system is TOXIC. The design, construction and examination rules for Normal Fluid Service are suitable for hazardous fluid services. By designating the service as category "M", the owner is specifying a higher level of design, construction and examination, which he may do even if the Code woud consider the system to be Normal Fluid Service. Just an clarification.

Regards, John.