AWS D1.1 clause structure, normative references, scope limitations, and efficient code navigation strategies for the open-book exam.
Navigating AWS D1.1
The AWS CWI Part C exam is an open-book test using the current edition of AWS D1.1 Structural Welding Code — Steel. Speed and accuracy in locating requirements is critical. The exam is not a memorization test — it is a navigation test. Candidates who have built a working index of key clauses consistently outperform those who try to read the code cold during the exam.
D1.1 High-Frequency Clause Locations:
- Prequalified WPS base metals: Table 3.1
- Prequalified joint details: Figure 3.3 (CJP groove), 3.4 (PJP groove), 3.5 (fillet)
- Minimum preheat and interpass: Table 3.3
- WPS essential variables: Table 4.5 (by process)
- Fillet weld acceptance criteria: Clause 6.9
- UT acceptance criteria: Clause 6.13.2
- RT acceptance criteria: Clause 6.12
- Electrode storage requirements: Clause 5.6
- Welder continuity: Clause 4.26
Tab your code book before the exam. Recommended tabs: Each major clause (1–8), each commonly referenced table (3.1, 3.3, 4.5, 4.11, 6.9, 6.13), and each Annex you expect to use.
Effective weld area, minimum/maximum sizes, PJP and CJP requirements, and the design basis for fillet and groove welds under D1.1 Clause 2.
Weld Sizing and Effective Length
Clause 2 of D1.1 governs the design of welded connections. The inspector uses this clause to verify that welds are the correct size and are located where designed. Undersized or mislocated welds are defects that require correction even if they otherwise look sound.
Fillet Weld Sizing Rules (D1.1 Table 2.4):
- For base metal thickness ≤ 1/4": minimum weld size = 1/8"
- For 1/4" < t ≤ 1/2": minimum = 3/16"
- For 1/2" < t ≤ 3/4": minimum = 1/4"
- For t > 3/4": minimum = 5/16"
Maximum Fillet Weld Size:
- Along edges of material < 1/4" thick: equal to material thickness
- Along edges ≥ 1/4" thick: material thickness minus 1/16"
Effective Length: Minimum = 4× weld size; if shorter, actual strength = L×size/4×size capacity. Start/stop craters not counted in effective length.
D1.1 Clause 2.3 (effective throat), Table 2.4 (minimum fillet weld sizes), Clause 2.7 (maximum weld sizes).
Conditions for prequalified status — base metal groups, joint geometry limits, filler metal requirements, and variables that void prequalified status.
Prequalified WPS Requirements
A prequalified WPS is one that conforms to all requirements of D1.1 Clause 3 and therefore does not require procedure qualification testing (no PQR needed). However, 'prequalified' does not mean 'unreviewed' — the WPS must still be a written document and must still conform to every applicable variable.
Conditions for Prequalified Status:
1. Base metal must be from D1.1 Table 3.1 list
2. Filler metal must be from the approved lists for that process (Table 3.2)
3. Joint geometry must conform to prequalified details (Figures 3.3–3.5)
4. Preheat and interpass temperature must meet Table 3.3
5. Weld position must be a standard position (1F–4F, 1G–4G)
6. No EGW, ESW, or automated processes (those require qualification)
Variables That Void Prequalified Status:
- Groove angle below minimums in Figures 3.3–3.5
- Root opening outside tolerance
- Base metal not listed in Table 3.1
- Process combination not permitted
- Using prohibited fillers for the electrode/process
D1.1 Clause 3, Table 3.1, Table 3.2, Table 3.3, Figures 3.3–3.5.
Welder performance qualification tests — specimen types, position groups, test ranges, 6-month continuity rule, and documentation requirements.
WPQ Test Requirements
Welder performance qualification (WPQ) certifies that an individual can produce a weld meeting code requirements. The test is process-specific, position-specific, and filler-metal F-number specific. The inspector must verify that the welder's qualification covers the actual production conditions.
WPQ Test Specimens (Plate, complete joint penetration):
- Bend tests: 2 root bends for plate ≤ 3/8"; 2 root + 2 face for plate > 3/8"; 4 side bends for plate ≥ 1"
- Acceptance: No open discontinuity > 1/8" in any direction
Qualification Ranges (D1.1):
- Material thickness: Qualified to unlimited thickness when test plate ≥ 3/8"
- Pipe diameter: 2G on pipe ≥ 24" qualifies all diameters horizontally; 6G qualifies all positions/diameters
WPQ Expiration:
- 6 months without use of the process voids qualification
- Inspector must verify current status by reviewing WPQ date and employer's continuity log
Record Requirements: WPQ must be signed by a CWI or the manufacturer/contractor representative.
D1.1 Clause 4.18 (WPQ tests), Table 4.11 (qualified positions), Clause 4.26 (continuity).
Plate preparation, fit-up requirements, electrode storage, preheat, interpass temperature control, weld repairs, and peening restrictions.
Fabrication Requirements
Clause 5 governs how welding is performed. Violations of Clause 5 requirements are the most common sources of weld defects — poor fit-up, improper electrode handling, and ignored preheat requirements account for the majority of rework on structural steel projects.
Low-Hydrogen Electrode Storage (D1.1 Cl. 5.6):
- Must be purchased in hermetically sealed containers OR stored in ovens at ≥ 250°F (120°C)
- Exposure time after removal from oven: 4 hours maximum (E7018, E8018 type) before return to oven or discarding
- Reconditioned electrodes: Not permitted to be reconditioned more than one additional time
Preheat Verification:
- Minimum distance from joint: 3" (75 mm) in each direction
- Verification: Temperature-indicating crayons, contact pyrometers, or thermocouple
- Duration: Maintain until weld is complete or hydrogen diffusion is assured
Weld Repairs:
- Excavate to sound metal before rewelding
- Re-inspect full length of repair with same methods as original
- Repair welds on tensile fatigue members: Consult engineer
Peening: Not permitted on root pass or final pass; intermediate passes only with engineer approval.
D1.1 Clause 5.6 (electrodes), 5.11 (preheat), 5.12 (interpass temperature), 5.25 (weld repairs), 5.31 (peening).
VT acceptance limits for undercut, size, profile, cracks, and porosity under D1.1 Clause 6; statically vs cyclically loaded member distinctions.
Visual Inspection Acceptance Criteria
Clause 6 contains all inspection and testing requirements, including acceptance criteria for visual, RT, UT, MT, and PT. An inspector must know which clause applies based on connection type (statically loaded, cyclically loaded, tube) and whether the member is tension or compression.
Fillet Weld Visual Acceptance (D1.1 Cl. 6.9, Statically Loaded):
- Cracks: None permitted
- Undercut: ≤ 1/32" (1 mm) for main member welds; ≤ 1/16" (2 mm) for secondary members
- Overlap: None permitted
- Crater cracks: None permitted
- Weld profiles: Per Figure 6.4; convexity ≤ 1/16" + 0.10×weld size
- Porosity: ≤ 3/8" diameter in any linear inch; ≤ 3/4" in any 12" length
Additional Requirements for Cyclically Loaded Members:
- Undercut: ≤ 1/32" for all members in tension
- Porosity: Not permitted in groove welds in tension
- Toe cracks: Zero tolerance
Weld Size Verification: Fillet weld gages (go/no-go or adjustable) are the standard field tools. A weld measuring less than the specified size is deficient and must be corrected by adding a cover pass.
D1.1 Clause 6.9 (visual acceptance, statically loaded), Clause 6.10 (cyclically loaded), Figure 6.4 (weld profiles).
RT and UT acceptance criteria for groove welds; D1.1 Clause 6 NDT frequency requirements; interpretation of film and UT reports.
RT and UT Acceptance Under D1.1
D1.1 specifies RT or UT as the supplemental NDT method for complete-joint-penetration (CJP) groove welds in primary members. The engineer specifies which method and the extent of testing. Both methods have distinct acceptance criteria — the inspector must apply the correct criteria for the method used.
RT Acceptance Criteria (D1.1 Cl. 6.12, Statically Loaded):
- Cracks: None permitted
- Incomplete fusion, incomplete joint penetration: None permitted
- Porosity — individual pore: ≤ 3/8" max diameter; ≤ T/3 (where T = thinner part)
- Cluster porosity: ≤ 3/4" in greatest dimension
- Slag inclusions: ≤ 2/3 T in length; multiple: separation ≥ 6× longer discontinuity
UT Acceptance Criteria (D1.1 Cl. 6.13, Statically Loaded):
- Uses dB rating system; Class A rejection applies regardless of rating
- Class A (always reject): Any indication interpreted as crack, incomplete fusion, or incomplete penetration
- Class B (reject if ≥ -8 dB): Slag and porosity type indications
- Class C (reject if ≥ 0 dB): Elongated inclusions
RT Quality Level: Required IQI (penetrameter) sensitivity per ASTM E1025 or E747. Essential wire/hole must be visible on the radiograph.
D1.1 Clause 6.12 (RT acceptance), Clause 6.13 (UT acceptance), Annex K (UT procedure), Figure 6.6 (RT IQI requirements).
Stud base material requirements, drawn arc and short cycle processes, pre-production qualification, inspection, and repair procedures under D1.1 Clause 7.
Stud Welding Inspection Requirements
Clause 7 of D1.1 governs the welding of shear studs to structural steel. The composite action of steel beams with concrete slabs depends entirely on the shear transfer capacity of properly welded studs. Stud inspection is thus a critical path inspection item in composite construction.
Pre-Production Testing (D1.1 Cl. 7.6.1):
- Minimum 2 test studs on each combination of stud type, base metal, and equipment setting per shift
- Bend tests: Studs bent 30° from vertical using hammer blow; must not fracture
- Torque test (alternative): Per manufacturer's recommendation
- If test studs fail: Reject and retune the equipment
Production Inspection (Cl. 7.7):
- After welding: 360° visible weld flash required (absence indicates problem)
- Bend test — field acceptance: ≥ 5° tilt without fracture
- Missing flash or incomplete circumferential weld: Reject
Repair:
- Rejected studs: Can be replaced by adding a second stud adjacent (within 2 diameters)
- Removal required: Torch-cut, grind base metal flush, verify base metal integrity before replacement
D1.1 Clause 7 (stud welding); AISC 360 Chapter I (composite design basis); AWS D1.1 Cl. 7.7.2 (inspection).
Clause 8 requirements for welding on existing structures — investigation, assessment, procedure requirements, and controls for in-service repair.
Repair and Strengthening Under Clause 8
Clause 8 provides requirements for welding on existing (in-service) structures. This work has additional hazards: the base metal chemistry may be unknown, the steel may be contaminated with paint or coatings, and the structure may be under load during repairs. The inspector must verify that the applicable investigation and procedure steps have been followed before any heat is applied.
Clause 8 Key Requirements:
- Chemical analysis: Required unless the steel is identifiable and matches an approved material
- Prequalification: Cannot use prequalified WPS without base metal identification — qualification testing is required
- Load state: Engineer must verify that welding under load is acceptable; residual stresses and distortion under load differ from shop conditions
- Heat input control: More critical than new construction — avoid stress concentrations in existing members
- Hardness testing: Often required to verify base metal chemistry indirectly before procedure selection
Inspection Controls:
- MT or PT before and after repair to confirm crack extent and repair completeness
- UT or RT on critical connections after repair
- Document chain of custody of test results
Required records for WPS, PQR, WPQ, inspection reports, NCRs, and final certification under D1.1 and standard quality management practice.
CWI Documentation Obligations
The CWI's signature on an inspection report is a professional certification that the described inspection was performed and the findings are accurately recorded. Incomplete or inaccurate documentation is a professional ethics violation regardless of whether the work itself was sound.
Required Documentation Sets:
WPS Package: Written WPS + supporting PQR(s) + filler metal certifications + base metal MTRs
Welder Files: WPQ test records + continuity log (dated entries for each process used)
Inspection Records: Pre-weld checklist, in-process log (interpass temps, sequence), NCR log, NDT reports
Final Certification: Statement signed by CWI that all work was inspected and conforms to contract documents
NCR (Nonconformance Report) Requirements:
- Specific code reference for the violation
- Location and dimensions of the deficiency
- Proposed correction method
- Re-inspection result and disposition
- NCR must be closed before final sign-off
Record Retention: D1.1 does not specify retention periods — the contract or owner's QA program governs. Industry standard for structural steel is minimum 5 years for primary connection records.
D1.1 Clause 6.1 (inspection responsibilities); AWS QC1 (standard for AWS CWI certification program); AISC 207 (quality management systems for steel fabricators).