Direct Answer
AWS D1.1 (Structural Welding Code — Steel) is the American Welding Society's specification governing the design, fabrication, and inspection of all structural steel welds. It is the governing code because it is referenced by AISC 360 (the structural steel design standard) and by the International Building Code — making compliance with AWS D1.1 a legal requirement on virtually every structural steel project in the United States.
Full Explanation
AWS D1.1 covers: prequalified joint geometries and procedures, WPS and PQR requirements, welder qualification, inspection methods, acceptance criteria for visual and NDT inspection, stud welding, and repair procedures. The code is updated periodically (D1.1:2020 is the current edition). Key sections for fabricators: Section 3 (prequalified joints), Section 4 (design), Section 7 (fabrication), Section 8 (inspection). The special inspector on your project will reference D1.1 when performing weld visual inspection.
What This Means for Your Shop
Your weld procedures and welder qualifications must meet D1.1 requirements. If your project has seismic requirements, additional provisions from AWS D1.8 (Seismic Supplement) apply, including requirements for Demand Critical welds (CJP welds in moment connections).
Common Mistakes
Using an older edition of D1.1 when the project specification references a newer edition. Changes between editions can affect prequalified joint geometry or inspection acceptance criteria.
Recommended Process
At project kickoff, confirm with the engineer which edition of AWS D1.1 governs the project. Verify your WPS documents reference the correct edition. Brief your special inspector on the edition in use.