Welding Lot
Welding Lot
(OP)
We are constructing to B31.3 and have determined what we are going to define as a welding lot. We have a pipe spool in one of our welding lots that has not been fabricated correctly to the drawing. We need to cut out several welds to correct the piping spool. Should the cut out welds be considered when determining our x-ray percentage for the lot? If the welds were being cut out due NDE finding weld defects then the welds would definitely have to be considered. However, these welds are being cut out because of a fitting error and will not be part of the final product. Is the intent of B31.3 to have a lot include all welds including fitting mishaps or just all welds that will be apart of the final product and put into service?





RE: Welding Lot
RE: Welding Lot
RE: Welding Lot
RE: Welding Lot
RE: Welding Lot
The Code is not going to provide guidance for every possible scenario, this is where common sense and good engineering design take over. Take a step back and think about what 343 Examination in B31.3 states.
341.3.3 Defective Components and Workmanship.
An examined item with one or more defects (imperfections
of a type or magnitude exceeding the acceptance
criteria of this Code) shall be repaired or replaced; and
the new work shall be reexamined by the same methods,
to the same extent, and by the same acceptance criteria
as required for the original work.
If part of the piping system had been fabricated, installed and examined during erection of the final or permanent piping system and a nonconformance was detected which required this component to be removed and re-worked, I would say one could take credit for the fabrication welds as part of the weld lot.
If during the course of fabrication the section of line contained welds and an error was discovered, which required the component to be re-welded or re-worked before installation, I would say no to considering these welds as final fabrication welds as part of the weld lot. In-situ fabrication and examination are process parameters that should be addressed in your Quality Manual.