D1.1, Table 9.14 1

[jrtei]

Table 9.14 lists the diameter range qualified as "Nominal Pipe or Tube Size Qualified, in". So which is it; nominal pipe or tube size? Should I assume it's nominal pipe size; as that is how they list it for your test coupon size "Nominal Size of Test Pipe, in"?
This table seems flawed in many other respects as well. For instance, if you can weld 6" nominal pipe you are qualified to weld unlimited pipe diameters. But if you weld 2" pipe you can't weld anything larger than 4" pipe. Huh? Even a plate qualification allows you to weld on pipe greater than 24" OD.

 

[SectionIX]

In general terms, tubing is used as a structural member while pipe is used to transport a gas or liquid. For AWS D1.1, with respect to welder qualification, there is no difference between tube/pipe, hence the way it is written. As far as qualified OD is concerned, each code/specification, whether ASME, API, or AWS based has their own rationale and set of standards.

Feel free to send AWS a list of perceived flaws...I'm sure they will be quick to respond, lol...(sarcasm intended)