D1.1 Inspection for CWI Part C: Clause 8 and Table 8.1

What inspection questions ask

Inspection is the third of the big Part C content areas. AWS sets each of them at a minimum of 25% of scored questions. In D1.1:2020, nearly everything you need is in Clause 8, Inspection (Clause 6 in D1.1:2015).

Most inspection questions fall into two groups: who does what (inspector roles, qualifications and duties), and whether a described weld is acceptable. The second group depends on reading Table 8.1 accurately.

How Clause 8 is organized

Know the parts so you can jump to them:

• Part A, General Requirements. Types of inspection, inspector qualification, and inspection of materials, WPSs, welder qualifications and work.
• Part B, Contractor Responsibilities. What the contractor must do, including correcting deficiencies and handling NDT that was not in the contract.
• Part C, Acceptance Criteria. Visual criteria in Table 8.1, then RT, UT, MT and PT acceptance.
• Part D onward. NDT procedures, NDT personnel qualification and the details of RT and UT.

Inspectors and their duties

D1.1 separates two kinds of inspection:

• Fabrication/erection inspection and testing is the contractor's responsibility.
• Verification inspection and testing is done for the Owner when the contract documents call for it.

Part A then covers:

• Who can be the inspector. It lists the accepted bases, including AWS CWI certification under QC1. It also sets a regular eye examination for inspectors and assistant inspectors.
• Assistant inspectors. They may do specific tasks under the inspector's supervision.
• What the inspector checks, and when. Materials, WPSs and welder qualifications before welding; work during and after welding.
• Marking and records. The inspector marks or records accepted work and keeps records of qualifications.
• Doubtful welders. If a qualified welder's work looks below standard, the inspector may require a simple demonstration test or full requalification.

Part B makes the contractor, not the inspector, responsible for visual inspection and for correcting all deficiencies in materials and workmanship.

Reading Table 8.1

Table 8.1, Visual Inspection Acceptance Criteria, has a row for each discontinuity category. Its columns are for statically loaded nontubular, cyclically loaded nontubular and tubular connections. A mark in a column tells you which criterion applies to that connection type.

The rows, and what each one depends on:

• Cracks. No size allowance at all.
• Fusion. Required between weld and base metal and between layers.
• Crater cross section. Craters must be filled, with one narrow exception.
• Weld profiles. Refers you back to the Clause 7 profile requirements.
• Time of inspection. Usually once the weld cools to ambient temperature, with a longer wait for certain high-strength steels.
• Undersized welds. Depends on the specified fillet size and on how much of the weld length is undersized. A special rule applies at girder ends.
• Undercut. Depends on loading type, material thickness and, for cyclic loading, the weld's orientation to stress.
• Porosity. Depends on loading type, weld type and orientation, with limits per inch and per 12 in. of weld.

Undersized welds: a worked example

A specified 1/4 in. fillet weld is 36 in. long. A continuous 4 in. stretch measures 3/16 in.; the rest is full size. It is not a web-to-flange weld.

1. Underrun depth. Table 8.1 allows a fillet to run under its nominal size by an amount that grows with the nominal size. For a 1/4 in. fillet the allowance is 3/32 in. The actual underrun is 1/16 in., so the depth is acceptable.
2. Undersized length. The undersized portion may not exceed 10% of the weld length. Ten percent of 36 in. is 3.6 in., and 4 in. is more.
3. Result. The weld is rejectable on length, even though the depth is within the allowance.

Always read the allowance for the specified size. A 3/16 in. fillet and a 5/16 in. fillet have different allowances from a 1/4 in. fillet.

NDT acceptance and personnel

• MT and PT. Welds examined by MT or PT in addition to visual inspection are judged against the visual criteria.
• UT. Indications are rated, then sorted into severity classes using the UT acceptance tables. There is one table for statically loaded and one for cyclically loaded connections. To read them, you need the indication rating, the weld thickness and the probe angle. The class then sets whether length matters. The largest class is rejected outright, the smallest is accepted, and the middle classes have length limits.
• NDT personnel. The code names the ASNT documents used to qualify NDT personnel, other than visual inspectors, in the Part D provisions.

NDT that was not in the contract

Part B covers NDT that the Owner asks for after the contract is set. It says who must perform or allow the testing, who pays, and when the contractor pays instead (fraud or gross nonconformance).

Exam technique for acceptance questions

1. Identify the connection type: statically loaded, cyclically loaded or tubular.
2. Identify the weld type and its orientation to stress.
3. Note the material thickness when undercut is involved.
4. Find the row in Table 8.1, then the column.
5. Do the arithmetic on scratch paper: totals per inch, totals per 12 in., percent of length.

Mark J. Curry tip: tab Table 8.1 and write the three column headings on the tab itself. It saves a few seconds on every acceptance question.

Common traps

• Applying a thick-plate undercut allowance to plate under 1 in.
• Using one fixed underrun allowance for every fillet size.
• Forgetting the 10% length limit on undersized fillets.
• Accepting a small crack because it is "only" 1/16 in. long.
• Judging MT or PT indications with criteria from another code.
• Mixing up the contractor's duty to correct deficiencies with the inspector's role to identify them.

Related: how to pass CWI Part C with the D1.1 code book.

Practice this domain

Sources

The D1.1 Inspection questions cite these documents, by document and, where we can confirm it, chapter or section. We never reproduce them.

1. AWS D1.1 (42 questions)

Found a mistake? Use "Report a problem" under any question, and Mark J. Curry checks it.

Questions? support@cwiready.com