B31.3 Radiography requirements

[1THN1]

Article 344.5.2 specifies 100% radiography for girth and miter groove welds in paragraph (a) and random radiography for the same welds in paragraph (b). How do I discriminate between the two rules?

We have a pipe to pipe butt weld 55mm thick.
(We do not have a fabricated branch connection)

 

[stanweld]

I think that you may be confused. The extent of examination is defined in Section 341.4. Section 344.5.2 provides for which type of welds RT is applicable.

 

[1THN1]

Thanks for your comment, but my confusion is really in the fact that girth and miter groove welds are both specified in paragraph 344.5.2 as 100%RT in (a) and random in (b).

 

[stanweld]

The rules in 344.5.2(a) apply to those miter and girth welds in pipe systems subject to 100% examination per 341.4.3.
The rules in 344.5.2(b) apply to those miter and girth welds in pipe systems subject to random examination under 341.4.1(b) and M341.4(b).