7.3 Inspection Planning and Flaw Expectations

7.3 Inspection Planning and Flaw Expectations

Quick Answer: A Level III inspection plan is built from what can go wrong in this material and process, not from a generic method menu. Define expected discontinuities, choose primary and supplemental methods, write procedures and work instructions, validate techniques on representative conditions, confirm supplier capability, and document results so decisions are traceable. Timing—in-process vs final vs in-service—matters as much as the method letter codes.

Domain 2 competencies on application of NDT methods and Domain 4 process knowledge meet here. If you can name every discontinuity but cannot plan an inspection sequence, or if you can list methods but cannot connect them to casting vs forging vs welding risks, you are not yet operating at Level III Basic exam level.

Plan From Flaw Expectations

Manufacturing-process map

Start with the product’s history:

Expected orientation drives technique details: longitudinal vs transverse magnetization for bar; angle selection for weld bevel sidewalls; scan patterns that cross the dominant crack direction.

Design and loading context

Criticality changes coverage. A non-structural bracket may need only VT per drawing notes. A pressure-retaining weld in cyclic service may need full volumetric coverage, surface crack methods, and defined re-inspection intervals. Level III planning connects consequence of failure and code classification to sampling vs 100% coverage, not personal preference.

Building the Inspection Plan

A practical plan answers:

1. What items / welds / regions are in scope (including repair welds and attachment welds often forgotten)?
2. When is each exam performed (fit-up VT, in-process, after PWHT, final, after hydro, in-service)?
3. Which methods and techniques for each region, with procedure numbers?
4. What coverage and scanning (percent, grid, automated vs manual, double-wall vs single-wall RT)?
5. What acceptance standard applies (code paragraph, client spec, drawing note)?
6. What happens on reject (repair, re-exam extent, engineering disposition)?
7. Who is qualified/certified for the method, and who interprets?
8. What records are retained and how long?

Work instructions vs procedures

• NDT procedures (Level III developed/approved as required by the written practice and code) define technical essentials: method, technique, equipment, calibration, sensitivity, evaluation, reporting.
• Work instructions / travelers / scan plans make the procedure executable on this job: joint IDs, access platforms, surface prep steps, sequence relative to welding/PWHT/coating, hold points, and form numbers.

A common failure mode is a beautiful procedure that the shop cannot perform as written (no access for film placement; coating applied before PT; PWHT after final MT with no re-exam). Level III planning walks the process flow with fabrication engineering.

Supplemental Examinations

Supplemental methods are used when:

• The primary method’s physics leave a blind spot (e.g., RT for volume + MT/PT for surface cracks).
• An indication needs characterization (e.g., UT to size a planar reflector after RT screening, or surface NDT to confirm a crack-like edge).
• Client or code requires layered defense (VT + PT + UT).
• Geometry blocks one method on part of the item (use an alternate qualified technique on restricted zones).

Supplemental does not mean optional decoration. If the plan’s detection logic depends on the second method, it is required, with the same rigor for certification, calibration, and documentation.

Validate Procedures and Techniques

Before production reliance—and whenever essential variables change—validate that the technique can find the discontinuities of concern under representative conditions:

• Calibration standards and DAC/TCG or equivalent appropriate to the material and geometry.
• Demonstration blocks with artificial or real flaws of relevant type, size, and orientation when codes or client specs require performance demonstration.
• Procedure qualification for special materials (coarse-grain austenitics, castings, composites, clad) where generic carbon-steel practices fail.
• Blind or administered checks of personnel performance when the written practice or contract requires them.
• Process control for PT/MT materials (contamination, temperature, UV intensity, field strength).

Validation is how Level III converts “method X can find cracks” into “this procedure on this geometry finds these cracks at the required sensitivity.”

Supplier Capability Evaluation

When NDT is outsourced or performed at a fabricator, evaluate capability before critical production—not after a failed audit:

Capability evaluation is both technical and quality-system work. A supplier with excellent welders but uncalibrated UT thickness gauges is not “capable” for corrosion mapping deliverables.

Documentation of Results

Documentation closes the plan. Minimum content typically includes:

• Item identity, heat/serial/weld ID, and revision of drawing/spec.
• Procedure and revision, method, technique, and equipment IDs.
• Personnel identification and certification level.
• Examination extent, surfaces, and any limitations (access, geometry, coating).
• Calibration/sensitivity references and status.
• Indications: location, size/characterization as required, evaluation against acceptance criteria.
• Disposition: accept, reject, repair, engineering use-as-is with reference.
• Date, signatures, and retention per code/contract.

Incomplete records break traceability: you cannot prove coverage, cannot support fitness-for-service, and will fail external audits. Level III systems define what “complete” means and sample records for compliance—not only review exotic flaw calls.

Putting It Together: Mini Scenarios

Scenario A — Cast pump casing (carbon steel): Expect shrinkage, porosity, hot tears. Plan VT of accessible surfaces + RT of critical sections per casting specification + MT of machined sealing faces for cracks after finish machining. Validate RT IQI/sensitivity on representative thickness. Document film/part correlation carefully.

Scenario B — Longitudinal seam on API-style line pipe: Expect LOF, LOP, cracks, porosity. High production rate may favor automated UT over RT for volume, plus surface NDT of the OD/ID as specified. Validate automated UT against reference pipe standards; control paint/coating sequence so surface methods remain valid.

Scenario C — In-service insulated pressure vessel: Expect corrosion under insulation and fatigue at nozzles. Plan insulation removal strategy or profile RT/guided-wave/UT thickness programs as applicable; VT of exposed metal; LT after nozzle repairs. AE might support global monitoring during a controlled pressure test but does not replace thickness assessment of CUI without a defined program.

Exam Focus: Planning Logic

Test items often hide the answer in process history or sequence errors:

• Final PT performed before machining that opens the critical surface.
• Only VT specified for a weld class that codes treat as requiring volumetric NDT.
• Supplier approved on ISO certificate alone without method-specific NDT capability review.
• No re-exam after repair.
• Acceptance criteria omitted from the work instruction so Level IIs “use judgment” inconsistently.

The Level III Basic candidate who plans from flaw expectations → method physics → procedure validation → executable instructions → records will outpace one who only memorizes method abbreviations.