The 2026 edition of AWS D1.1 introduces several structural changes that directly impact fabrication shops: prequalified WPS limits for fillet welds have been tightened, and the acceptance criteria for ultrasonic testing now reference AWS D1.1 Annex K as the default instead of Annex S. These adjustments matter because misapplying the wrong annex can lead to rejected welds and costly rework.
The shift from Annex S to Annex K for UT acceptance aligns D1.1 with modern phased array capabilities, which provide better sizing accuracy for planar defects. Annex K uses a distance-amplitude correction (DAC) curve based on side-drilled holes, while Annex S relied on a simpler reference block method. The Fabricator has noted that shops using PAUT will benefit from fewer false calls, but those still on conventional UT must update their procedures.
Per the Fabricator, the 2026 D1.1 also clarifies essential variables for flux-cored arc welding (FCAW) prequalified joints, adding wire classification as an essential variable for the first time. This means a change from E71T-1 to E71T-9 requires requalification, even if other parameters remain the same.
When updating your WPS library:
- Check that all prequalified FCAW joints list the specific AWS A5.20 classification; generic "FCAW" is no longer sufficient.
- Verify UT procedures reference Annex K if using phased array; Annex S is still permitted for conventional UT but must be explicitly stated.
- Review fillet weld sizes for prequalified joints: the new edition reduces maximum single-pass fillet size for some wire diameters.
- Ensure welder qualifications cover the new essential variables if your shop uses multiple FCAW wire types.
A common oversight is assuming prequalified status never changes. The 2026 D1.1 removes several legacy prequalified joint details that had been carried over from earlier editions. Shops that do not review their WPS against the new edition risk nonconformance.
How is your team handling the transition to AWS D1.1 2026?