Dear, I see in section 6 in multiple qualification.....but i think it's saying about when branch and run pipe size is equal.....(is it ...?), how about, if i want to do qualification in different size(36" X 2",3",4"6").....?
If we're still talking about WQT, then the criteria of 6.2.2 applies for single qualification. It gets pretty confusing here to communicate what you've done and what the welder is qualified for when applying the single qual criteria to branch connections. Both the run pipe and the header diameters need to be identified if different. So potentially, the qualification could look like - Welder "A" is qualified to weld <2" NPS branch pipe or fittings to run pipe pipe diameters 2" NPS to 12" NPS in the position welded (process, electrode group and progression are essential variables). Much easier just to follow section 6.3 and weld on matching diameters for the welder qualification for documentation purposes. You can find interpretations from API 1104 subcommittee on this issue if needed.
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