9.1 AWS D1.1:2025 Code Structure and Navigation
Key Takeaways
- AWS D1.1:2025 has 11 clauses plus normative/informative annexes; learn which question type each clause answers, not page numbers
- Scope: steel structures, base metal 1/8 in [3 mm] and thicker, specified yield up to 100 ksi [690 MPa] — not ASME, API, D1.2, D1.3, or D1.4 work
- Tab the ten key references: Tables 5.3, 5.4, 5.8, 7.7, 8.1, 8.2 and Figures 5.1, 5.2, plus the welding-symbol and form annexes
- Part C is open-book and tests locate/interpret/apply/cross-reference, not memorization
- Budget roughly 2 to 3 minutes per question; mark and return rather than stalling
- Use the Table of Contents and Index before flipping; decide the target clause from the stem before opening the book
The Code Behind Part C
AWS D1.1/D1.1M:2025 — Structural Welding Code – Steel is the most commonly selected code book for Part C of the Certified Welding Inspector (CWI) exam. Part C is open-book, so it does not reward memorization — it rewards the ability to locate, interpret, and apply a requirement quickly. The candidate who knows exactly where preheat lives, which figure shows a prequalified joint, and which row of Table 8.1 governs undercut will finish; the candidate who reads cover-to-cover will run out of time.
D1.1 governs the welding of statically and cyclically loaded steel structures built from carbon and low-alloy steels with a specified minimum yield strength up to 100 ksi [690 MPa] and a base-metal thickness of 1/8 in [3 mm] and thicker. It does not cover pressure vessels (ASME), pipelines (API 1104), sheet steel under 1/8 in (that is D1.3), reinforcing bar (D1.4), or aluminum (D1.2). Knowing the scope limit in Clause 1 is itself a common Part C trap.
The Eleven Clauses (2025 Renumbering)
The 2020 edition renumbered the historic nine clauses to a normative structure that the 2025 edition keeps. Learn what type of question each clause answers:
| Clause | Title | The question it answers |
|---|---|---|
| 1 | General Requirements | Scope, base-metal/strength limits, definitions of roles, responsibilities |
| 2 | Normative References | Which other standards (ASTM, AWS A5.x, ASNT) are invoked |
| 3 | Terms and Definitions | Exact A3.0-based meaning of a term used in the code |
| 4 | Design of Welded Connections | Allowable/ design strength, effective throat/area, fatigue categories |
| 5 | Prequalification of WPSs | When you may skip PQR testing — joints, metals, fillers, preheat |
| 6 | Qualification | How to qualify a WPS by test (PQR) and qualify welders/operators |
| 7 | Fabrication | Workmanship: cutting, fit-up, tolerances, profiles, repair |
| 8 | Inspection | Inspector duties, NDT methods, visual/UT/RT acceptance criteria |
| 9 | Stud Welding | Arc stud welding application, qualification, and inspection |
| 10 | Tubular Structures | Round/box tubular connection design, qualification, acceptance |
| 11 | Strengthening and Repair | Modifying or repairing existing welded structures in service |
Annexes Matter Too
After the clauses, normative annexes (mandatory when referenced) and informative annexes (guidance) follow. Candidates should tab the annex that lists standard welding symbols, the ASTM/filler-metal grouping annex, and sample WPS/PQR/qualification forms. A question that says "per the code, what symbol element indicates field weld?" sends you to an annex, not a clause.
What Part C Actually Tests
Part C consists of 150 questions in the closed-book half is Part A; Part C is the code-book module of roughly 46 questions answered with your tabbed D1.1 in hand. Questions fall into recognizable patterns:
- Locate a value ("what is the minimum preheat for…?")
- Interpret a table or figure (read a prequalified joint detail's tolerances)
- Apply criteria to a scenario ("a 1/32 in undercut on a 14 in static fillet — accept or reject?")
- Cross-reference clauses (use Table 5.3 steel category to enter Table 5.8 preheat)
Tabbing and Navigation Strategy
- Tab by destination, not by page. Color-code Clause 5 (prequalification), Clause 7 (workmanship), and Clause 8 (acceptance) differently; add bright tabs on Table 5.3, 5.4, 5.8, 7.7 (min fillet size), 8.1 (visual), and 8.2 (UT).
- Use the Table of Contents and Index first. They are faster than flipping; the index points to the exact clause for a term.
- No permanent marking inside the book — tabs are allowed, but highlighting/writing in the code is typically prohibited; confirm the AWS rules for your exam date.
- Budget your time. With about 130 minutes for the module, you have roughly 2 to 3 minutes per question. If a value will not surface in 3 minutes, mark it, move on, and return.
- Read the stem before opening the book — decide which clause/table you need, then open once.
A Map of Where Things Live
Internalizing this mental map turns a 3-minute hunt into a 20-second lookup. Memorize the home clause for each common topic so you open the book exactly once:
| If the question is about... | Go to |
|---|---|
| Scope, strength limit, definitions of inspector roles | Clause 1 |
| Effective throat, weld strength, fatigue stress category | Clause 4 |
| "Is this WPS prequalified?", joint details, preheat | Clause 5 |
| Qualifying a WPS by test (PQR), welder/operator tests | Clause 6 |
| Minimum fillet size, fit-up tolerance, weld profile, repair | Clause 7 |
| Inspector duties, visual/UT/RT acceptance, re-inspection | Clause 8 |
| Studs / shear connectors | Clause 9 |
| HSS and pipe connections | Clause 10 |
Worked Navigation Example
Suppose Part C asks: "For SMAW on 1-1/4 in A572 Gr 50 with low-hydrogen electrodes, what is the minimum preheat?" The path is a two-table cross-reference: (1) open the base-metal table to read the steel category for A572 Gr 50; (2) carry that category and the 1-1/4 in thickness into the preheat table (5.8); (3) read the minimum temperature at the intersecting cell. A candidate who tabs both tables and knows the lookup order solves it in under a minute. A candidate who starts reading Clause 5 text from the top will burn three minutes and may still miss it.
Editions and Why They Matter
The 2025 edition is current; the 2020 edition introduced the modern 11-clause numbering and the SI-then-USC presentation. Older study material may cite the legacy nine-clause scheme (where Inspection was Clause 6, not 8). On exam day you use whatever edition AWS issues for your seat — read the spine and the table-of-contents numbering before you start tabbing, because clause and table numbers shifted between editions. Never answer a navigation question from an outdated tab set.
For the Exam: Most candidates who fail Part C do so on time, not knowledge. Practice timed code drills until you can land on any of the ten key tables in under fifteen seconds.
A Part C question asks for the allowable design strength and effective throat of a partial-joint-penetration groove weld. Which AWS D1.1 clause should you open?
A welder asks whether AWS D1.1 can be used to weld 16-gauge (0.060 in) sheet steel for a structure. Per the code scope, what is correct?
A question requires the minimum preheat for SMAW on 1-1/4 in A572 Gr 50. What is the correct navigation path through AWS D1.1?