We have welders testing for the D1.8 Supplemental Welder Qualification for Restricted Access Welding. The question has come up if we can weld the root pass with a 1/8 diameter rod, and all subsequent passes with a larger 5/32 diameter rod to complete the joint.

D1.8 references Table 4.12 Welding Personnel Performance Essential Variables Changes Requiring Requalification. Item (4) clearly states "to a diameter or thickness not qualified". My interpretation is that if we qualify the welder using 1/8 at the root, and then change over to a 5/32 rod to fill the restricted access joint during the welder qualification, we will satisfy the requirement of item (4). Is this your understanding as well? We would also need to include this in our WPS.