An OSHA-compliant handrail system on a warehouse mezzanine. Six fillet welds join 2″ Schedule 40 pipe posts to ¼″ base plates, SMAW E7018, specified ¼″ fillet size. Five welds passed. Weld W4 was rejected for continuous weld size under-run: the fillet leg measured 3/16″ instead of ¼″ over a 4″ run — exceeding the 2″ continuous-under-run limit per Cl. 6.9.5. A cover pass was added, and re-inspection accepted the weld.
Frequently Asked Questions
What is the weld size under-run rule in AWS D1.1?
Clause 6.9.5 permits weld size to be under-run by up to 1/16" provided the under-run is not continuous for more than 2" in any 12" of weld length. W4 was 1/16" short for 4" continuously — this exceeded the 2" continuous limit, making it rejectable even though the per-inch magnitude was at the limit.
How do you fix a weld size under-run rejection?
The simplest fix is a cover pass (additional weld pass) to build the leg size to the specified dimension. The cover pass must follow the approved WPS. The re-inspection checks the final leg size with a fillet gauge.