ConstantEffort
Mechanical
- Dec 29, 2012
- 72
I believe I have found two ASME interpretations of ASME Section VIII Div 1 that are inconsistent concerning the RT number of vessels fabricated from welded pipe. Am I missing something?
VIII-1-01-150 – ERW pipe + seamless heads, spot radiography category B & C welds per UW-11(a)(5)(b). Shall be marked as RT-2.
VIII-1-07-10 – ERW pipe + seamless heads, full radiography category B welds per UW-11(a). Shell be marked as RT-4.
The spot radiography interpretation seems to indicate that the long seam of the pipe should be ignored.
The full radiography interpretation seems to indicate that the long seam of the pipe should be considered.
Why would it be different? Why would a full radiography yield a "worse" rating (RT-4) than spot radiography per (a)(5)(b) (RT-2)? (I know RT-4 is not, strictly speaking, worse than RT-2, but that is a common perception in the circles I work in.)
VIII-1-01-150 – ERW pipe + seamless heads, spot radiography category B & C welds per UW-11(a)(5)(b). Shall be marked as RT-2.
VIII-1-07-10 – ERW pipe + seamless heads, full radiography category B welds per UW-11(a). Shell be marked as RT-4.
The spot radiography interpretation seems to indicate that the long seam of the pipe should be ignored.
The full radiography interpretation seems to indicate that the long seam of the pipe should be considered.
Why would it be different? Why would a full radiography yield a "worse" rating (RT-4) than spot radiography per (a)(5)(b) (RT-2)? (I know RT-4 is not, strictly speaking, worse than RT-2, but that is a common perception in the circles I work in.)
