AWS D1.1: Structural Welding Code - Steel
Comprehensive welding standard for structural steel covering welder qualification, welding procedures, inspection, and acceptance criteria. AWS D1.1 is the primary standard for structural welding in the United States. Compliance is required for building and bridge construction. Welder and inspector certifications per AWS D1.1 are industry credentials.
The American Welding Society (AWS) publishes the welding codes that name the qualified procedures, qualified welders, and weld-NDE acceptance criteria used across structural and fabrication contracts.
Building codes (e.g. AISC 360) cite AWS D1 directly; structural steel work in the U.S. is effectively gated by AWS qualification packages.
AWS D1.1 is invoked when the scope of work matches its title — structural welding code - steel — and when the contract or regulatory regime cites it as the controlling document. In power and nuclear work, the inspection plan is built directly off the standard's tables; an auditor will cite the paragraph that was followed (or the one that was missed) when writing a finding. In fabrication shops the standard is reproduced inside the written procedure book and referenced from every inspection report so that the auditor's paper trail leads back to the same paragraph the inspector worked from.
Methods covered
Industries
- Construction
- Bridge
- Manufacturing
- Power Generation
- Personnel qualification: examinations under AWS D1.1 must be performed by inspectors qualified and certified to a recognised scheme (typically ASNT SNT-TC-1A, CP-189, or ISO 9712 depending on jurisdiction), with documented training hours, vision tests, and a controlling written practice.
- Written procedure: every examination requires a written, controlled procedure that names the method, equipment, calibration steps, scanning pattern, and acceptance criteria — and is qualified before first use.
- Equipment verification: ultrasonic instruments must be verified against a calibration block (V1, V2, IIW, or job-specific reference) at intervals defined by the procedure — typically before use, every four hours of scanning, on operator change, and at end of shift.
- Image-quality verification: every radiograph or digital exposure carries a penetrameter / IQI of the type and thickness specified by the standard; the IQI must be visible and at the required sensitivity for the radiograph to be acceptable.
- Radiation safety: source handling, exclusion zones, dosimetry, and source recordkeeping must follow the licensing authority's rules in addition to the inspection standard itself.
- Magnetic-particle technique: magnetisation method (yoke, prods, central conductor, multidirectional), field strength verification (pie gauge, Hall-effect meter, or QQI), and demagnetisation are all specified in the written procedure.
- Penetrant process control: penetrant family (visible / fluorescent), sensitivity level, dwell times, removal method (solvent / lipophilic / hydrophilic), and developer type are all controlled and documented for each examination.
- Acceptance criteria: indications are evaluated against the standard's tabulated limits (length, depth, alignment, frequency); any indication exceeding the criteria is recorded, dispositioned, and either repaired or evaluated for fitness-for-service.
- Documentation: examination reports must include enough information for a third party to reproduce the inspection — equipment serial numbers, calibration records, inspector ID, sketches of indications, and the controlling procedure revision.
- Latest Edition
- 2025
- First Published
- 1928
- Scope
- Structural Welding Code — Steel; covers design, qualification, fabrication, inspection of welded steel structures (≥ 1/8 inch thick).
- Acceptance Criteria
- Cl. 6.12 tables — separate static vs cyclic; UT acceptance via Table 6.2 with dB rating system.
- Calibration / Qualification
- Welding personnel per Cl. 4; CWI inspectors per AWS QC1; NDE per AWS D1.1 + AWS QC1 / SNT-TC-1A.
Key Clauses Inspectors Cite
- Cl. 4 — Qualification (WPS, PQR, welder)
- Cl. 5 — Fabrication
- Cl. 6 — Inspection (NDE methods, acceptance)
- Cl. 6.12.2 — Statically Loaded Acceptance
- Cl. 6.12.3 — Cyclically Loaded Acceptance
Companion / Parent Standards
AWS D1.5 (bridge welding) · AWS D1.6 (stainless) · AWS D1.8 (seismic supplement) · AISC 360 · AWS QC1 (CWI)
Sample Contract Language
“All welding shall comply with AWS D1.1/D1.1M:2025; NDE per Cl. 6 with cyclically-loaded acceptance criteria; CWI present during fabrication.”
AWS D1.1 is maintained on its publishing organisation's revision cycle. The version cited in any contract or written inspection program should be tracked so that revisions can be reviewed against the existing inspection plan and any clause changes worked into the next procedure update.
A power-generation outage applies AWS D1.1 to the in-service inspection scope: tube bundles, boiler welds, and pressure-part attachments are examined on the schedule defined by the program, and findings are tracked through repair, re-inspection, and the next outage cycle.
What does AWS D1.1 cover?
AWS D1.1 (Structural Welding Code - Steel) is published by AWS (American Welding Society). Comprehensive welding standard for structural steel covering welder qualification, welding procedures, inspection, and acceptance criteria.
What is the history of AWS D1.1 and the most common misuse to avoid?
AWS D1.1 (Structural Welding Code – Steel) is the dominant US structural-steel welding code. First published in 1928 as AWS A1, it is now the controlling document for structural-steel welding under AISC 360 and IBC building codes. Revised on a 4-5 year cycle; the 2020 edition added expanded Annex L on UT acceptance. D1.1 acceptance criteria for UT (Annex L) versus RT (Section 8 Part C) are different — same indication can be acceptable by RT but rejectable by UT (or vice versa). Inspectors mixing methods on the same weld must apply each method own table, not interchange them.
Which sister standards is AWS D1.1 typically used with?
AWS D1.1 (steel) is paired with D1.2 (aluminum), D1.5 (bridge welding), and D1.6 (stainless steel) for the full structural-welding code family.
Is AWS D1.1 mandatory or voluntary?
AWS D1.1 is a consensus standard. It becomes mandatory when invoked by a contract, by another code that cites it (for example ASME Section V calling out an ASTM practice), or by a regulator that has adopted it into law in a specific jurisdiction.
Who is qualified to perform inspections under AWS D1.1?
Inspections under AWS D1.1 must be performed by personnel qualified and certified to a recognised NDT certification scheme — most commonly ASNT SNT-TC-1A or CP-189 in the United States, ISO 9712 in much of the rest of the world, and NAS 410 for aerospace work. The written practice that controls qualification must be in place before any examination is started.
Which other standards are commonly cited alongside AWS D1.1?
AWS D1.1 is most often cited together with the parent code that brings it into the contract — typically ASME Section V or VIII for U.S. pressure equipment, AWS D1.1 for structural welding, API 510/570/653 for in-service petroleum equipment, or the matching EN/ISO standard for European and international work.
Standard Code
AWS D1.1
Organization
AWS (American Welding Society)
Methods Covered
5 method(s)
Industries
4 sector(s)
Need clarification on NDT terminology used in AWS D1.1?
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