NDT Inspection Procedure: Complete Step-by-Step Guide for Inspectors
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Introduction
Non-Destructive Testing (NDT) is an important part of quality control and inspection because it allows materials, welds, components and structures to be examined without damaging their intended serviceability.
However, reliable NDT does not depend only on selecting a testing method and performing an examination. A proper NDT inspection procedure involves several stages, starting with reviewing the applicable drawings and specifications and continuing through examination, evaluation, acceptance, documentation and reporting.
An inspector may have the correct equipment and technical knowledge, but an inspection can still produce an unreliable result if the wrong procedure, examination extent, calibration requirement or acceptance criterion is used.
A systematic NDT inspection procedure helps ensure that:
- The correct component is inspected.
- The correct NDT method is selected.
- Approved procedures are followed.
- Equipment is suitable and properly verified.
- Personnel are appropriately qualified.
- Examination results are evaluated against the correct requirements.
- Indications are properly documented.
- Final reports contain traceable inspection information.
This guide explains the NDT inspection process step by step, with practical points that NDT technicians, inspectors, engineers and beginners can use during actual inspection work.
What Is an NDT Inspection Procedure?
An NDT inspection procedure is a controlled sequence of instructions used to perform a non-destructive examination on a particular material, component, weld or structure.
The procedure normally defines important requirements such as:
- Applicable NDT method
- Material or component to be examined
- Examination area
- Examination extent
- Equipment requirements
- Calibration or verification requirements
- Surface preparation
- Examination technique
- Sensitivity requirements
- Evaluation method
- Acceptance criteria
- Recording requirements
- Reporting requirements
The exact requirements depend on the NDT method, component, project specification, applicable code or standard and examination purpose.
For example, the procedure used for Magnetic Particle Testing of a carbon-steel weld will not necessarily be the same as the procedure used for Ultrasonic Testing of a welded joint.
This is why an inspector should never assume that a familiar inspection technique automatically satisfies the requirements of every project.
Why Is an NDT Inspection Procedure Important?
A written and properly controlled procedure provides consistency.
Without a defined procedure, two inspectors could examine the same component using different techniques and obtain different results. Differences in equipment settings, examination coverage, surface preparation, sensitivity or evaluation criteria can affect the reliability of the inspection.
A good NDT procedure helps control these variables.
1. Consistency
The examination can be performed using defined steps rather than individual preference.
2. Traceability
Inspection results can be connected to the component, weld number, procedure, equipment and personnel involved.
3. Compliance
The inspection can be performed according to the applicable project requirements, specifications, codes and standards.
4. Repeatability
If re-examination is required, another qualified technician can understand how the original examination was performed.
5. Quality control
The procedure provides a reference against which inspection activities can be reviewed.
NDT Inspection Procedure — Step-by-Step Process
A typical inspection can be divided into the following stages:
Document Review → Component Identification → Code/Specification Review → Method Selection → Procedure Verification → Personnel Qualification → Equipment Verification → Surface Preparation → Examination → Evaluation → Acceptance → Documentation → Reporting → Re-examination if Required
The exact sequence can vary depending on the project and NDT method, but these stages provide a useful practical framework.
Step 1: Review Drawings and Inspection Documents
Before beginning the examination, the inspector should first understand what needs to be inspected and what requirements apply.
Important documents may include:
- Engineering drawings
- Weld maps
- Inspection and Test Plan (ITP)
- Project specifications
- Purchase specifications
- Applicable codes and standards
- Approved NDT procedures
- Previous inspection records
- Repair records
- Examination requests
The inspector should identify the component correctly before starting the examination.
Practical Tip
Never begin an NDT examination simply because a component has been presented for inspection.
First verify the identification, drawing reference, weld number, material and required examination.
A wrong-component inspection can produce technically correct NDT results that are still useless because the wrong location was examined.
Step 2: Identify the Material and Component
The NDT method must be suitable for the material and inspection objective.
The inspector should confirm information such as:
- Material type
- Material thickness
- Component geometry
- Weld type
- Weld configuration
- Heat treatment condition where relevant
- Surface condition
- Weld identification
- Component identification number
For example, Magnetic Particle Testing requires a material that can be sufficiently magnetized, while Liquid Penetrant Testing is primarily used to reveal surface-breaking discontinuities.
Similarly, Ultrasonic Testing depends heavily on material properties, thickness, geometry and access.
Practical Tip
Before selecting a method, ask:
What type of discontinuity am I trying to detect, and is this NDT method capable of detecting it under the actual inspection conditions?
That simple question prevents many method-selection errors.
Step 3: Review Applicable Codes and Standards
The inspector must determine which requirements govern the examination.
Depending on the project, these may include:
- ASME requirements
- AWS requirements
- ASTM standards
- ISO standards
- API requirements
- Project specifications
- Client specifications
- Approved engineering requirements
The applicable document may define the examination method, extent, technique, evaluation requirements or acceptance criteria.
For example, the requirements for performing an examination are not necessarily the same as the requirements used to determine whether an indication is acceptable.
Important Point
Do not confuse an examination standard with an acceptance criterion.
An NDT standard may explain how to perform the examination, while a construction code, specification or contractual document may establish what indications are acceptable or rejectable.
Step 4: Select the Correct NDT Method
The method should be selected based on:
- Material
- Expected discontinuity type
- Location of discontinuities
- Component geometry
- Thickness
- Accessibility
- Required sensitivity
- Project requirements
Common NDT methods include:
- Visual Testing (VT)
- Liquid Penetrant Testing (PT/LPT)
- Magnetic Particle Testing (MT/MPT)
- Radiographic Testing (RT)
- Ultrasonic Testing (UT)
- Phased Array Ultrasonic Testing (PAUT)
- Time of Flight Diffraction (TOFD)
- Eddy Current Testing (ECT)
Each method has strengths and limitations.
For example:
PT is useful for surface-breaking discontinuities on suitable non-porous surfaces.
MT is suitable for detecting surface and near-surface discontinuities in ferromagnetic materials.
RT provides a radiographic image that can reveal certain volumetric and planar discontinuities depending on orientation and technique.
UT can detect and locate internal reflectors and is widely used for weld examination and thickness measurements.
VT is often performed before, during and after fabrication and can identify visible surface conditions and weld profile issues.
The best method is therefore not simply the most advanced method—it is the method that is technically appropriate for the inspection objective and applicable requirements.
Recommended Internal Reading
For a general introduction to the major NDT methods, readers can continue with your existing NDT Methods Overview article.
For method-specific procedures, the relevant PT, MT, RT, UT, VT, PAUT, TOFD or ECT guides can be linked from the appropriate sections of this article.
Step 5: Verify the Approved NDT Procedure
Before starting the examination, confirm that the procedure being used is the correct and current approved revision.
Check:
- Procedure number
- Revision number
- Approval status
- Applicable NDT method
- Material/component covered
- Examination technique
- Equipment requirements
- Calibration requirements
- Examination parameters
- Evaluation requirements
- Acceptance criteria or referenced acceptance document
Practical Tip
One of the simplest mistakes to prevent is using an old procedure revision.
Always verify the revision before beginning the inspection.
Personnel Qualification, Equipment- Verification, Examination & Evaluation
Step 6: Verify NDT Personnel Qualification
Before performing an NDT examination, verify that the technician or inspector is qualified for the method and level required by the applicable project requirements.
Depending on the certification system and project, personnel qualification may involve:
NDT method certification
Certification level
Relevant training
Vision requirements
Experience requirements
Employer authorization
Project-specific qualification
Client approval where required
Common NDT certification levels include:
Level I — Performs specific tasks under supervision according to written instructions.
Level II — Performs examinations, interprets and evaluates results within the applicable requirements, and prepares reports.
Level III — Provides technical direction, develops or approves procedures where authorized, and provides higher-level technical oversight.
The exact responsibilities depend on the applicable certification scheme, employer system and project requirements.
Practical Tip
Before starting the inspection, check the technician's:
Name → NDT Method → Certification Level → Validity → Employer Authorization → Project Requirements
Do not assume that certification in one NDT method automatically qualifies a person to perform another method.
For example, qualification in UT does not automatically mean the technician is qualified to perform RT, MT or PT.
Step 7: Verify NDT Equipment
The equipment used for an examination should be suitable for the method and capable of achieving the required examination sensitivity.
Depending on the NDT method, equipment may include:
PT Equipment
Penetrant
Cleaner/remover
Developer
UV-A light where applicable
Visible light source
Temperature measuring equipment where required
MT Equipment
AC/DC yoke or magnetizing equipment
Magnetic particles
Test pieces or verification devices
UV-A light for fluorescent examinations
Light meter where required
UT Equipment
Ultrasonic flaw detector
Probes/transducers
Calibration blocks
Couplant
Cables and accessories
RT Equipment
X-ray or gamma-ray source
Film or digital detector
IQI
Densitometer where applicable
Processing equipment where applicable
VT Equipment
Lighting
Inspection gauges
Mirrors
Magnifiers
Borescope or videoscope where required
The equipment should be checked according to the applicable procedure and project requirements.
Equipment Identification and Calibration
Before examination, verify:
Equipment identification number
Calibration status
Verification status
Due date where applicable
Accessories
Probe/transducer identification
Calibration block identification
Condition of equipment
An equipment calibration sticker alone should not replace the checks required by the approved procedure.
Some equipment requires calibration, while particular checks may be described as verification, depending on the equipment, standard and procedure.
Practical Tip
Record the equipment identification in the inspection report whenever the procedure or project requires it.
This improves traceability if the inspection result is later questioned or reviewed.
Step 8: Prepare the Inspection Surface
Surface preparation is one of the most important parts of an NDT examination.
The surface should be suitable for the selected method and sufficiently clean to prevent contamination or surface conditions from interfering with the examination.
Possible surface contaminants include:
Oil
Grease
Dirt
Rust
Scale
Paint
Welding spatter
Moisture
Loose particles
However, the required preparation depends on the NDT method.
For example, PT generally requires a clean surface because contaminants can prevent penetrant from entering surface-breaking discontinuities.
MT also requires appropriate surface conditions so that particles can form reliable indications.
For UT, surface condition can affect probe coupling and scanning.
For VT, lighting, accessibility and cleanliness can directly affect what the inspector can see.
Practical Tip
Do not automatically grind or remove coatings unless the approved procedure or applicable requirement calls for it.
Unnecessary surface preparation can alter the component surface and may itself introduce problems.
Step 9: Perform the NDT Examination
Once the documents, personnel, equipment and surface have been verified, the actual examination can begin.
The technician should follow the approved procedure rather than relying on memory or personal preference.
The examination may involve different stages depending on the method.
Example — PT
A typical PT sequence may include:
Pre-cleaning
Application of penetrant
Dwell time
Excess penetrant removal
Developer application
Development time
Inspection
Evaluation
Post-cleaning where required
Example — MT
A typical MT examination may involve:
Surface preparation
Magnetization
Application of magnetic particles
Observation of indications
Evaluation
Demagnetization where required
Final cleaning where required
Example — UT
A UT examination may involve:
Equipment setup
Calibration
Reference sensitivity
Scanning
Recording relevant indications
Location and sizing
Evaluation against applicable requirements
Example — RT
RT may involve:
Identification of the weld/component
Selection and positioning of the source and detector
IQI placement
Exposure
Image processing or digital image acquisition
Image quality verification
Interpretation
Evaluation
The actual sequence must always follow the applicable procedure and standard.
Step 10: Monitor Examination Conditions
During the examination, the inspector should verify that the required examination conditions remain within the specified limits.
Depending on the method, these can include:
Surface temperature
Ambient conditions
Lighting
UV-A intensity
Equipment settings
Couplant condition
Scanning speed
Examination coverage
Penetrant dwell time
Developer time
Exposure parameters
Calibration status
Environmental conditions can significantly affect the reliability of some examinations.
For example, inadequate lighting can affect visual inspection, while unsuitable surface conditions can affect PT or MT results.
Practical Tip
If an examination condition falls outside the permitted range, do not simply continue and assume the result is acceptable.
Stop and determine what action the applicable procedure requires.
Step 11: Identify and Record Indications
An indication is a response or signal observed during an NDT examination that may be associated with a discontinuity or another source.
Not every indication is automatically a defect.
The inspector should first determine:
Is the indication real?
Then:
What type of indication is it?
And finally:
Does it meet the applicable acceptance criteria?
Depending on the method, the indication may be:
Linear
Rounded
Surface-breaking
Subsurface
Volumetric
Planar
Geometric
Non-relevant
The terminology and evaluation method depend on the NDT technique and applicable standard.
Step 12: Evaluate the Indication
Evaluation is different from simply detecting an indication.
Detection answers:
Is there an indication?
Evaluation asks:
What is the indication, where is it located, how large is it, and does it meet the applicable requirements?
The inspector may need to determine:
Location
Orientation
Length
Width
Height/depth where applicable
Number of indications
Spacing
Distribution
Type or classification
Relevant/non-relevant status
The applicable NDT procedure and acceptance standard should be followed.
Important Point
An indication is not automatically a rejectable defect.
A component should only be classified as acceptable or rejectable according to the applicable acceptance criteria.
For example, an indication may be detectable but still acceptable if it falls within the permitted limits.
Step 13: Distinguish Relevant and Non-Relevant Indications
Some NDT methods can produce responses that are not caused by unacceptable material discontinuities.
The inspector must therefore determine whether an indication is relevant to the inspection objective.
Possible sources of non-relevant responses can include:
Geometry
Surface configuration
Keyways
Threads
Changes in section
Equipment effects
Magnetic permeability variations
Poor coupling
Surface contamination
Processing artifacts
The method-specific procedure should explain how such indications are handled.
Practical Tip
Never reject a component simply because an indication is visible.
First establish:
Indication → Cause → Relevance → Size/Extent → Acceptance Criteria → Final Disposition
This sequence helps prevent unnecessary rejection and incorrect acceptance.
Step 14: Apply the Correct Acceptance Criteria
After an indication has been evaluated, compare the result with the applicable acceptance criteria.
Acceptance criteria may come from:
Construction codes
Product standards
Project specifications
Engineering specifications
Client requirements
Contract documents
Referenced standards
The acceptance criteria should be identified before final disposition.
Example
Suppose an ultrasonic examination detects a reflector.
Detection alone does not establish rejection.
The inspector may need to evaluate:
Reflector location
Signal response
Length
Depth
Orientation
Applicable evaluation requirements
The result is then compared with the acceptance criteria specified for that particular examination.
Critical Practical Rule
Never select an acceptance criterion simply because it is familiar.
The applicable project document must determine which criterion applies.
Step 15: Record Inspection Results
A good NDT inspection record should provide enough information to establish what was examined, how it was examined and what was found.
Depending on the method and project, records may include:
Project name
Client
Component identification
Weld number
Drawing number
Material
Thickness
NDT method
Procedure number
Procedure revision
Examination extent
Equipment identification
Calibration/verification information
Technician name
Certification level
Examination date
Examination result
Indication details
Acceptance criteria
Final disposition
Report number
For RT, records may additionally include image or film identification.
For UT, scan details and relevant indication information may be required.
For PT and MT, indication location, type and dimensions may need to be recorded.
Practical Tip
A good inspection report should allow another qualified person to understand what was inspected and how the conclusion was reached.
Step 16: Prepare the NDT Inspection Report
The inspection report is the formal record of the examination.
A report should be clear, traceable and consistent with the applicable procedure and project requirements.
A typical report may contain:
Identification
Project
Client
Component
Weld number
Drawing/reference number
Examination Information
NDT method
Procedure number
Procedure revision
Examination extent
Date
Personnel
Technician/inspector
Certification level
Certification identification where required
Equipment
Equipment identification
Probe/accessory information where applicable
Calibration/verification details
Results
Indications detected
Location
Size
Evaluation
Acceptance criteria
Final result
Approval
Inspector signature/electronic approval
Reviewer/Level III approval where required
Client/witness approval where applicable
Step 17: Repair and Re-Examination
If an examination identifies a rejectable condition, the next step is normally controlled disposition according to the applicable project process.
Possible actions may include:
Record the indication.
Notify the responsible quality/welding personnel.
Establish the required repair or disposition.
Perform the repair according to an approved process.
Re-examine the repaired area.
Record the re-examination results.
Close the relevant inspection record when requirements are satisfied.
The exact repair and re-examination requirements depend on the applicable code, specification and project procedure.
Practical Tip
Never simply erase or overwrite the original failed result.
Maintain traceability between:
Original Examination → Indication → Repair → Re-Examination → Final Disposition
This is particularly important for quality records and audits.
Practical NDT Inspection Flow
A simple way to remember the overall process is:
1. Review Documents
↓
2. Identify Component
↓
3. Confirm Applicable Code/Specification
↓
4. Select NDT Method
↓
5. Verify Approved Procedure
↓
6. Verify Personnel Qualification
↓
7. Verify Equipment
↓
8. Prepare Surface
↓
9. Perform Examination
↓
10. Detect Indications
↓
11. Evaluate Indications
↓
12. Apply Acceptance Criteria
↓
13. Record Results
↓
14. Prepare Report
↓
15. Repair/Re-examine if Required
↓
16. Final Disposition
This workflow can be adapted to different NDT methods and project requirements.
Practical Tip for NDT Inspectors
The most important principle is:
Do not inspect from memory—inspect against the approved procedure and applicable requirements.
Experienced inspectors may perform familiar examinations many times, but every project can have different requirements.
Always verify the documents before starting.
Part 3: Real NDT Inspection Scenario — Practical Example, Common Mistakes & Correct Actions
3.1 A Realistic NDT Inspection Scenario
Consider a fabrication project involving a pressure-vessel nozzle weld. The weld has been completed and the inspection plan requires NDT examination before the component proceeds to the next stage.
The NDT technician arrives at the inspection area with the applicable procedure, inspection equipment, calibration records, drawings and reporting documents.
At first glance, the job appears straightforward: identify the weld, perform the required examination, evaluate the indications and prepare the report.
However, many inspection problems occur before the actual examination begins.
A professional NDT technician should therefore treat the inspection as a controlled process rather than simply performing a test and recording a result.
3.2 Step 1 — Verify the Correct Component and Weld
Before starting the examination, the technician should confirm:
Component identification
Drawing number and revision
Weld number
Joint location
Material specification
Thickness
Examination method
Examination extent
Applicable procedure
Applicable acceptance criteria
Example
The inspection request states:
Weld No. N-105 — Nozzle-to-shell circumferential weld — UT examination required.
The technician should physically confirm that the weld marked N-105 is the weld being examined.
Common Mistake
A technician examines a nearby weld because the weld numbers are difficult to read or the inspection request contains several welds.
Correct Action
Stop the examination and verify the weld identification against the drawing, weld map and inspection request.
Never assume that a nearby weld is the correct weld.
3.3 Step 2 — Verify the Applicable Procedure
The technician should use the approved procedure applicable to the examination.
The procedure may specify:
Equipment requirements
Calibration requirements
Examination technique
Surface condition
Coverage
Sensitivity
Scanning requirements
Evaluation requirements
Acceptance criteria
Reporting requirements
Common Mistake
Using an old procedure revision because a printed copy was left inside the technician's equipment bag.
Why This Is a Problem
A revised procedure may contain changes to examination technique, calibration, coverage or acceptance requirements.
Correct Action
Before beginning the inspection, confirm the procedure number and revision against the current controlled document.
Practical rule:
Always verify the revision before starting the examination—not after completing it.
3.4 Step 3 — Verify Personnel Qualification
The technician should have the required qualification for the examination method and scope of work.
Depending on the project requirements, the inspection organization may require evidence such as:
NDT certification
Method qualification
Level II authorization
Employer authorization
Vision examination records
Project-specific qualification
Common Mistake
A technician is qualified in UT but is assigned to perform an examination outside the scope of the technician's authorization.
Correct Action
Confirm personnel qualification before accepting the inspection assignment.
The inspection report should not be used to hide a personnel qualification problem.
3.5 Step 4 — Equipment Verification
The technician should verify that the equipment is suitable and within its required calibration or verification period.
Depending on the method, this may include:
UT
Instrument identification
Probe identification
Cable condition
Calibration block
Calibration status
Frequency
Range
Sensitivity
Reference level
Instrument identification
Probe identification
Cable condition
Calibration block
Calibration status
Frequency
Range
Sensitivity
Reference level
MT
Yoke or magnetizing equipment
Magnetic field verification where required
Consumables
Light source
Relevant field verification equipment
Yoke or magnetizing equipment
Magnetic field verification where required
Consumables
Light source
Relevant field verification equipment
PT
Penetrant
Cleaner/remover
Developer
Batch or expiry information where required
Lighting conditions
Penetrant
Cleaner/remover
Developer
Batch or expiry information where required
Lighting conditions
RT
Radiation source or X-ray equipment
Exposure equipment
Film or detector
IQI
Processing or image acquisition equipment
Radiation safety controls
Radiation source or X-ray equipment
Exposure equipment
Film or detector
IQI
Processing or image acquisition equipment
Radiation safety controls
VT
Lighting
Measuring equipment
Gauges
Magnification equipment where required
Surface access
Lighting
Measuring equipment
Gauges
Magnification equipment where required
Surface access
3.6 A Common Equipment Mistake
Imagine a UT technician begins scanning a weld and obtains apparently acceptable results.
Later, during document review, it is discovered that the calibration block used for the examination was not appropriate for the application.
The technician may have performed the scanning correctly, but the inspection result can still become questionable.
Correct Action
Equipment suitability and calibration should be confirmed before examination.
If a calibration problem is discovered after examination, do not simply change the report.
The affected examination should be assessed according to the applicable procedure and project requirements.
3.7 Step 5 — Surface Preparation
Surface condition can directly affect examination quality.
Depending on the method, the surface may need to be:
Clean
Dry
Free from loose scale
Free from excessive weld spatter
Free from oil or grease
Accessible for the required examination
Suitable for the examination technique
Example: PT
If oil or heavy contamination remains on the surface, penetrant may not properly enter surface-breaking discontinuities.
Example: MT
Excessive surface contamination may interfere with particle application or indication interpretation.
Example: UT
Rough weld reinforcement, excessive scale or poor probe contact can affect coupling and scanning.
Common Mistake
Starting the examination immediately because the production team says:
"The weld is ready."
The technician should independently verify whether the surface is actually suitable for the examination.
3.8 Step 6 — Perform the Examination
Once the prerequisites have been verified, the technician can perform the examination according to the approved procedure.
The technician should maintain control over:
Examination parameters
Required coverage
Scanning pattern
Equipment settings
Calibration checks
Environmental conditions
Relevant observations
The objective is not simply to "find a defect."
The objective is to produce a valid and traceable examination result.
3.9 Real Scenario: UT Weld Examination
Consider a butt weld requiring ultrasonic examination.
The technician performs the initial calibration and begins scanning.
During scanning, an indication appears on the screen.
The technician should not immediately write:
"Weld rejected."
An indication is not automatically a rejectable defect.
The technician needs to evaluate the indication according to the applicable procedure and acceptance criteria.
Important information may include:
Location
Position
Length
Depth
Amplitude
Orientation
Response characteristics
Relevant evaluation requirements
Only after evaluation can the indication be classified according to the applicable acceptance requirements.
3.10 Common Mistake: Calling Every Indication a Defect
This is one of the most important mistakes for inexperienced inspectors.
An indication is an observed response from the examination.
It does not automatically mean that a rejectable discontinuity exists.
For example, an indication may result from:
Geometry
Surface condition
Weld configuration
Coupling variation
Equipment response
Actual discontinuity
Correct Approach
Follow the examination procedure and evaluation requirements.
Do not make a rejection decision simply because an instrument display shows a signal.
3.11 Real Scenario: PT Examination
Suppose a technician performs Liquid Penetrant Testing on a weld.
The surface is cleaned and penetrant is applied.
After the required processing time, the developer is applied.
A linear indication appears near the weld toe.
The technician should:
Observe the indication.
Confirm that the examination process was correctly performed.
Evaluate the indication according to the applicable procedure.
Determine whether it is relevant.
Measure or record it as required.
Compare it with the applicable acceptance criteria.
Record the final result.
Common Mistake
The technician sees a red line and immediately reports:
"Crack."
That conclusion may be premature.
The indication must be properly evaluated before a final decision is made.
3.12 Real Scenario: MT Examination
During Magnetic Particle Testing, a technician observes a linear accumulation of magnetic particles.
The indication appears approximately perpendicular to the applied magnetic field.
The technician should investigate it according to the applicable procedure.
This is important because magnetic particle examination depends on the relationship between the magnetic field and the orientation of the discontinuity.
Common Mistake
Using only one magnetization direction when the procedure requires adequate coverage in multiple directions.
Correct Action
Follow the specified magnetization technique and coverage requirements.
3.13 Inspection Mistake: Wrong Acceptance Criteria
This is a serious documentation and technical error.
Suppose a technician performs an examination according to one specification but evaluates the result using acceptance criteria from another specification.
The examination itself may have been performed correctly, but the final result may still be invalid.
Correct Action
Before evaluation, verify:
Applicable code
Specification
Project requirement
Examination procedure
Acceptance criteria
Revision
Never copy acceptance criteria from another project simply because the inspection method is the same.
3.14 Inspection Mistake: Incomplete Weld Identification
Imagine that five welds are inspected during one shift.
The technician records:
"UT completed — acceptable."
But the report does not clearly identify the individual weld numbers.
This creates a traceability problem.
A good inspection record should allow another person to understand:
Which component → which weld → which examination → which result?
Correct Action
Use clear identification such as:
Component ID
Weld number
Drawing reference
Examination method
Examination date
Technician identification
Equipment identification
Result
3.15 Inspection Mistake: Ignoring Calibration Checks
Calibration is not necessarily a one-time activity performed at the beginning and forgotten.
The applicable procedure may require verification at specified stages or conditions.
Example
A UT technician completes several welds and later discovers that the instrument response has changed significantly.
The technician should not simply continue using the previous results without considering the procedure's calibration verification requirements.
Correct Action
Follow the procedure for calibration and verification before, during and/or after examination as applicable.
3.16 Inspection Mistake: Poor Reporting
A technically correct examination can still create problems if the report is incomplete.
A report may need information such as:
Project name
Client
Component identification
Weld number
Drawing number
Procedure number
Procedure revision
Examination method
Equipment identification
Calibration information
Material/thickness where required
Examination extent
Results
Acceptance criteria
Final status
Technician identification
Certification information
Date
Common Mistake
Writing only:
"NDT OK."
This provides very little technical traceability.
Better Practice
The report should contain enough information for an independent reviewer to understand what was examined, how it was examined and what requirement was used to evaluate the result.
3.17 What Happens When a Result Is Rejectable?
Suppose an indication is evaluated and does not meet the applicable acceptance criteria.
The technician should not hide the result or modify the inspection record to make the weld acceptable.
The normal workflow is:
Indication detected → Evaluation → Acceptance criteria → Accept/Reject → Documentation → Corrective action if required → Re-examination
The exact process depends on the project procedure and applicable code.
3.18 Mistake: Repair Without Proper Documentation
A rejected weld may be repaired by the fabrication team.
However, the original examination result should remain traceable.
The repair process may require:
Repair identification
Repair location
Repair method
Re-examination
New examination report
Link to the original report
Practical Tip
Never allow a repaired weld to become a "new weld" on paper simply because the original result was rejected.
Traceability between the original examination and the repair examination is essential.
3.19 Final Scenario — How a Professional Level II Technician Thinks
Imagine a technician is told:
"Please inspect this weld quickly. Production is waiting."
An inexperienced technician may immediately start the examination.
A professional technician thinks:
1. Is this the correct weld?
↓
2. Is the drawing/current revision available?
↓
3. Is the procedure applicable and current?
↓
4. Am I qualified and authorized for this examination?
↓
5. Is the equipment suitable and verified?
↓
6. Is the surface acceptable?
↓
7. Is the required examination coverage achievable?
↓
8. Are the examination parameters correct?
↓
9. Are the indications properly evaluated?
↓
10. Am I using the correct acceptance criteria?
↓
11. Is the result properly documented?
↓
12. Can another inspector trace this result later?
This is the mindset that separates simply performing an NDT test from performing a controlled inspection.
3.20 Level II Practical Rule
A Level II technician should remember:
Do not rush the inspection just because production is waiting.
Production pressure must not replace the requirements of the approved procedure, applicable specification or acceptance criteria.
A technically sound inspection is:
Correct component + Correct procedure + Qualified personnel + Suitable equipment + Proper examination + Correct evaluation + Complete documentation
3.21 Quick Inspection Mistake Checklist
Before signing an NDT report, ask:
☐ Correct component identified?
☐ Correct weld number verified?
☐ Current drawing/revision checked?
☐ Correct NDT procedure used?
☐ Personnel qualification verified?
☐ Equipment identification recorded?
☐ Calibration/verification valid?
☐ Surface condition acceptable?
☐ Required examination coverage achieved?
☐ Indications properly evaluated?
☐ Correct acceptance criteria applied?
☐ Examination result recorded clearly?
☐ Repair/re-examination traceability maintained where applicable?
☐ Report reviewed before submission?
If any critical requirement is uncertain, stop and resolve the issue before finalizing the inspection.
3.22 Key Takeaway
The most dangerous NDT mistakes are not always equipment mistakes.
Many occur because the inspector:
Examines the wrong weld
Uses an outdated procedure
Misses a calibration requirement
Ignores surface condition
Confuses indications with defects
Uses incorrect acceptance criteria
Fails to maintain traceability
Produces incomplete documentation
A good NDT inspection therefore begins before the first scan, exposure, particle application or penetrant application.
The technician's responsibility is not merely to produce an NDT result.
It is to produce a technically valid, traceable and properly documented inspection result.
For practical learning, readers can continue with the site's existing resources on NDT methods, welding defects, UT, RT, MT, PT, inspection reporting and NDT career development.
Part 4: NDT Report & Documentation — Complete Practical Guide for Level II Inspectors
4.1 Why NDT Documentation Matters
An NDT examination is not complete simply because the inspection has been performed.
The result must also be properly documented, traceable and reviewable.
An NDT report provides evidence that:
The correct component was examined.
The correct examination method was used.
The examination was performed according to an applicable procedure.
Required equipment and calibration checks were completed.
The examination covered the required area.
Indications were evaluated correctly.
Applicable acceptance criteria were used.
The final result was recorded.
The person performing the examination can be identified.
In fabrication, construction, maintenance and inspection projects, the NDT report may later be reviewed by a QC inspector, client inspector, third-party inspector, engineer or auditor.
Therefore, an NDT report should be written so that another competent person can understand what was examined and how the result was obtained.
4.2 What Is an NDT Report?
An NDT report is a controlled inspection record that documents the examination performed on a component, weld or material.
Depending on the examination method and project requirements, the report may contain:
Project information
Component information
Weld identification
Material information
Examination method
Procedure information
Equipment information
Calibration/verification information
Examination parameters
Examination extent
Indication information
Acceptance criteria
Examination result
Technician identification
Certification information
Date and location
Review and approval information
The exact requirements depend on the applicable procedure, specification, code and client requirements.
4.3 Basic Structure of an NDT Report
A practical NDT report can be divided into several sections:
Section 1 — Project Identification
Examples:
Project name
Client
Contractor
Fabricator
Location
Purchase order
Work order
Inspection request number
Section 2 — Component Identification
Examples:
Equipment number
Tag number
Component number
Line number
Drawing number
Drawing revision
Weld number
Section 3 — Examination Information
Examples:
NDT method
Examination procedure
Procedure revision
Examination extent
Examination date
Examination location
Section 4 — Equipment Information
Examples:
Instrument identification
Probe identification
Yoke identification
Radiation source identification
Detector identification
Light meter identification
Calibration/verification status
Section 5 — Examination Results
This section records:
Indications
Location
Size
Type/classification where applicable
Evaluation
Acceptance/rejection
Remarks
Section 6 — Personnel
Examples:
Technician name
Certification level
Certification number
Employer authorization
Signature or electronic approval
Section 7 — Review and Approval
Depending on project requirements:
NDT Level III review
QC inspection review
Client review
Third-party inspection
Approval status
4.4 Weld Identification Is Critical
One of the most important parts of an NDT report is identifying exactly what was examined.
For example:
Component: Pressure Vessel V-101
Weld: N-105
Drawing: DWG-2045
Revision: Rev. 03
This creates a traceable connection between the physical weld and the inspection report.
Common Mistake
A report states:
UT — ACCEPTABLE
but does not clearly identify the weld.
This creates a serious traceability problem.
Someone reviewing the report later may not know which weld was examined.
Practical Tip
Always ask:
Can another inspector locate the exact weld from my report?
If the answer is no, the identification is probably incomplete.
4.5 Examination Procedure and Revision
The report should identify the applicable examination procedure according to project requirements.
Example:
Procedure: UT-PRO-005
Revision: Rev. 02
The revision is important because procedures can change.
A report that only states:
Procedure: UT-PRO-005
may not provide sufficient document control if multiple revisions existed during the project.
Common Mistake
Using the current procedure revision in the report even though the actual examination was performed using an older revision.
Correct Action
The report should accurately reflect the procedure actually used, subject to the project's document-control requirements.
Never alter historical examination records simply to make them match a later revision.
4.6 Examination Method
Clearly identify the NDT method.
Examples:
PT — Liquid Penetrant Testing
MT/MPT — Magnetic Particle Testing
UT — Ultrasonic Testing
RT — Radiographic Testing
VT — Visual Testing
PAUT — Phased Array Ultrasonic Testing
TOFD — Time of Flight Diffraction
ECT — Eddy Current Testing
Where necessary, include the specific technique.
For example:
UT — Angle Beam Examination
or:
PT — Visible Dye, Solvent Removable Technique
The exact terminology should follow the applicable procedure.
4.7 Equipment Identification
Equipment should be traceable where required.
For UT, a report may include:
Instrument manufacturer/model
Instrument serial number
Probe type
Probe frequency
Probe serial number
Calibration/reference block
For MT:
Yoke identification
Equipment verification information
Lighting equipment where applicable
For PT:
Consumable identification where required
Batch information where required
Expiry information where applicable
Lighting verification where required
For RT:
Source identification
Exposure equipment
Detector/film information
IQI information
Other required exposure data
The exact fields depend on the applicable procedure.
4.8 Calibration and Verification Records
Calibration information is an important part of inspection traceability.
For example, a UT report may contain:
Instrument: UT-015
Probe: 4 MHz Angle Beam
Reference Block: IIW Block
Range: 100 mm
Sensitivity: As specified by procedure
The technician should record the required calibration or verification information rather than simply writing:
Calibration OK.
Practical Tip
Record enough information to demonstrate that the required verification was performed according to the applicable procedure.
4.9 Examination Coverage
The report should indicate the examination extent where required.
Examples:
100% examination
Spot examination
10% examination
Specified weld length
Specific area
Repair area
Local examination
Do not assume that "UT completed" means the entire weld was examined.
Example
If a project requires examination of a specific 300 mm weld length, the report should identify the examined area according to the project documentation.
4.10 Recording Indications
When relevant indications are detected, the report may need to record information such as:
Indication number
Location
Orientation
Length
Width where applicable
Depth where applicable
Amplitude or response where applicable
Type/classification where applicable
Evaluation
Disposition
The exact requirements depend on the examination method.
Important
Do not invent a discontinuity classification simply because a signal looks unusual.
The indication must be evaluated using the applicable procedure and acceptance criteria.
4.11 Indication vs Defect in the Report
The distinction is important.
An indication is an observed response from an NDT examination.
A discontinuity is an interruption or imperfection in the expected structure.
A defect is generally a discontinuity that is unacceptable under the applicable requirements.
Therefore, the report should not automatically label every indication as a defect.
Example
Instead of immediately writing:
Crack found — Reject
the technician should follow the applicable evaluation process and document the result according to the procedure and acceptance criteria.
4.12 Acceptance Criteria
The NDT report should identify the applicable acceptance criteria when required.
Examples could include:
Project specification
Engineering specification
Applicable construction code
Examination procedure
Client requirement
Critical Rule
The examination method and acceptance criteria are not the same thing.
For example, UT may be the examination method, while a separate code or project specification establishes the acceptance requirements.
Common Mistake
Using acceptance criteria from a previous project because:
"It was the same type of weld."
That is not a safe assumption.
Always verify the applicable requirements for the current job.
4.13 Final Result
The final result should be clear.
Examples:
ACCEPTABLE
or
NOT ACCEPTABLE
or the terminology required by the applicable procedure.
Avoid vague statements such as:
OK
Fine
No issue
Passed
unless those terms are specifically accepted by the project's reporting system.
A professional report should make the disposition unambiguous.
4.14 Example of a Simplified UT Report
NDT Examination Report
Project: Pressure Vessel Fabrication
Component: Vessel V-101
Weld No.: N-105
Drawing: DWG-2045
Revision: Rev. 03
Method: Ultrasonic Testing
Technique: Angle Beam UT
Procedure: UT-PRO-005
Procedure Revision: Rev. 02
Material: Carbon Steel
Thickness: 25 mm
Equipment: UT-015
Probe: 4 MHz Angle Beam
Reference Block: Applicable calibration block
Examination Extent: As specified by inspection request
Indications: No relevant rejectable indications detected.
Acceptance Criteria: As specified by the applicable project/code requirements.
Result: ACCEPTABLE
Technician: NDT Level II
Date: [Inspection Date]
Report No.: NDT-2026-00125
The above is only a simplified example. Actual report fields should follow the project's approved form and applicable requirements.
4.15 Repair Examination Reporting
Suppose a weld fails an examination.
The original report should not simply disappear after repair.
The repair should remain traceable.
A typical sequence may be:
Original Weld → Initial NDT → Reject → Repair → Re-NDT → Final Result
Example
Original report:
Weld N-105 — UT — Not Acceptable
Repair:
Repair Area N-105-R1
Re-examination:
UT — Acceptable
This allows the inspection history to be followed.
Common Mistake
Creating a new report that makes the repaired weld appear as though it had never failed the initial examination.
Correct Practice
Maintain traceability between the original examination, repair and re-examination according to project document-control requirements.
4.16 Corrections to NDT Reports
Mistakes can happen during documentation.
For example:
Wrong date
Typographical error
Wrong equipment number
Incorrect weld number
Missing information
The correction process should follow the project's document-control procedure.
Never:
Delete the original record without authorization.
Change a rejection to acceptance without technical justification.
Hide an examination result.
Backdate an inspection.
Modify records to satisfy production pressure.
Delete the original record without authorization.
Change a rejection to acceptance without technical justification.
Hide an examination result.
Backdate an inspection.
Modify records to satisfy production pressure.
Practical Tip
If an important error is discovered after report submission, inform the responsible inspection/document-control authority and correct it through the approved process.
4.17 Electronic NDT Reports
Modern inspection projects may use electronic reporting systems.
The same principles still apply.
An electronic report should provide:
User identification
Date/time
Component identification
Examination information
Equipment information
Results
Required approvals
Revision/change history where applicable
Electronic reporting does not remove the need for traceability.
4.18 Report Review Before Submission
Before submitting an NDT report, perform a final review.
Level II Self-Check
☐ Project number correct?
☐ Component number correct?
☐ Weld number correct?
☐ Drawing number correct?
☐ Drawing revision correct?
☐ Examination method correct?
☐ Procedure number correct?
☐ Procedure revision correct?
☐ Equipment identification correct?
☐ Calibration/verification information complete?
☐ Examination extent correct?
☐ Indications properly recorded?
☐ Acceptance criteria correct?
☐ Final result clearly stated?
☐ Technician identification complete?
☐ Date correct?
☐ Supporting documents attached where required?
☐ Repair/re-examination traceability maintained?
This final check can prevent many avoidable documentation errors.
4.19 Real-Life Documentation Mistake
Imagine that a technician performs UT on three welds:
N-101
N-102
N-103
The technician correctly examines all three.
However, while preparing the report, the results are entered against the wrong weld numbers.
The examination itself may have been technically sound, but the documentation now creates a traceability problem.
Lesson
Correct inspection + incorrect identification = unreliable documentation.
Always verify the physical component against the report before submission.
4.20 Documentation Mistake Caused by Production Pressure
A supervisor says:
"Just put acceptable for now. We will check the indications later."
This should not be accepted.
The NDT report must reflect the actual examination result and applicable evaluation.
The inspector's responsibility is to provide an accurate technical record.
Production schedules should not determine whether an inspection result is recorded as acceptable.
4.21 NDT Report Traceability Chain
A strong inspection record creates a traceability chain:
Project
↓
Component
↓
Drawing
↓
Weld Number
↓
Inspection Request
↓
NDT Procedure
↓
Qualified Technician
↓
Equipment
↓
Calibration/Verification
↓
Examination
↓
Indication Evaluation
↓
Acceptance Criteria
↓
Final Result
↓
Report
↓
Review/Approval
↓
Repair/Re-examination if required
This chain is one of the most important concepts for an NDT Level II technician to understand.
4.22 What an Auditor or Client Inspector May Ask
During an inspection review, an auditor or client inspector may ask:
Question 1:
Which weld did you examine?
The report should provide a clear answer.
Question 2:
Which procedure did you use?
The report should identify the procedure and applicable revision.
Question 3:
How do you know your equipment was suitable?
The report and supporting records should provide the required evidence.
Question 4:
What acceptance criteria did you use?
The technician should be able to identify the applicable requirement.
Question 5:
Who performed the examination?
The report should identify the qualified personnel.
Question 6:
Was this weld repaired?
The inspection documentation should allow the history to be traced where applicable.
Question 7:
Show me the original examination record.
The record should be retrievable through the document-control system.
4.23 The Golden Rule of NDT Documentation
A useful Level II rule is:
If it was not properly recorded, it may be difficult to prove that it was properly inspected.
Good documentation does not replace good inspection.
But good inspection without proper documentation can still create major project problems.
4.24 Five Questions Before Signing an NDT Report
Before signing or submitting the report, ask:
1. Did I inspect the correct item?
2. Did I use the correct procedure and requirements?
3. Did I record the examination accurately?
4. Did I evaluate the result against the correct acceptance criteria?
5. Can another competent person trace and understand my inspection?
If all five answers are clear, the report is much more likely to provide a useful and defensible inspection record.
4.25 Final Takeaway
NDT reporting is not administrative paperwork that comes after the "real" inspection.
It is part of the inspection process.
A professional NDT technician should understand that the final deliverable is not simply an NDT result.
It is:
A technically valid examination + accurate evaluation + complete documentation + traceability.
A properly prepared NDT report protects the technician, the inspection organization, the client and the integrity of the project.
The best report is one that another qualified person can review months later and still understand:
What was inspected → how it was inspected → what was found → how it was evaluated → what requirement was applied → what the final result was.
Readers can continue with the existing NDT Quality Hub resources covering NDT methods, welding inspection, inspection checklists, NDT report formats, ASME requirements, UT, RT, MT, PT, PAUT and TOFD.
Part 5: Repair & Re-Examination — Full NDT Site Scenario for Level II Inspectors
5.1 What Happens When an NDT Examination Fails?
An NDT inspection does not always end with an acceptable result.
During fabrication, an examination may identify an indication that, after proper evaluation, does not meet the applicable acceptance criteria.
When this happens, the correct response is not simply to write "REJECT" and walk away.
The result must be properly documented, the nonconforming condition must be controlled, the repair must be carried out according to the approved process, and the repaired area must be re-examined as required.
A simplified workflow is:
NDT Examination → Indication → Evaluation → Not Acceptable → Documentation → Repair → Re-Examination → Final Disposition
The exact requirements depend on the applicable code, specification, approved procedure and project quality system.
5.2 Full Site Scenario: Weld Failure During UT
Consider a pressure-vessel fabrication project.
A nozzle is welded to the vessel shell, and the inspection plan requires ultrasonic examination of the completed weld.
Project Information
Component: Pressure Vessel V-101
Weld: N-105
Material: Carbon Steel
Weld Type: Nozzle-to-shell weld
Examination: Ultrasonic Testing
Technician: NDT Level II
Procedure: Approved UT procedure
The weld has passed visual inspection and is released for UT.
5.3 Step 1 — Verify the Weld Before Examination
The Level II technician receives the inspection request.
Before starting, the technician verifies:
Vessel identification
Nozzle identification
Weld number
Drawing number
Drawing revision
Weld thickness
Examination extent
Applicable UT procedure
Acceptance criteria
Equipment status
The technician confirms that the physical weld is N-105.
This step is important because a perfect inspection performed on the wrong weld is still a failed inspection process.
5.4 Step 2 — Equipment and Calibration Check
The technician checks the UT equipment.
The required verification/calibration is performed according to the applicable procedure.
The technician confirms:
Instrument identification
Probe identification
Frequency
Calibration/reference block
Range
Sensitivity
Required reference levels
Equipment condition
The calibration results are recorded as required.
The technician is now ready to examine the weld.
5.5 Step 3 — Perform the Examination
The technician performs the examination according to the approved procedure.
During scanning, a significant response is observed.
The technician stops and investigates the response.
At this stage, the technician should not immediately declare a crack or reject the weld.
The signal must be properly evaluated.
5.6 Step 4 — Evaluate the Indication
The technician determines the relevant information required by the procedure.
For example:
Indication location
Position relative to weld reference point
Length
Depth/location through thickness where applicable
Signal characteristics
Amplitude/response
Orientation
Relevant evaluation requirements
The technician also checks whether the response could be related to weld geometry or another non-relevant source.
After evaluation, the indication is determined to be a relevant discontinuity.
The applicable acceptance criteria are then applied.
5.7 Step 5 — Determine the Result
Suppose the evaluated indication exceeds the applicable acceptance requirements.
The final examination result is therefore:
NOT ACCEPTABLE
The technician should not change the result simply because production is waiting.
The finding must be documented according to the project procedure.
5.8 Step 6 — Prepare the Initial NDT Report
The initial UT report records the examination accurately.
Example:
Component: V-101
Weld: N-105
Method: UT
Result: NOT ACCEPTABLE
Indication: Relevant indication requiring disposition according to applicable requirements.
Location: Recorded according to the approved reporting system.
The report should maintain traceability to the exact weld and inspection request.
5.9 Step 7 — Notify the Responsible QC/Inspection Team
The technician communicates the result through the project's established process.
Depending on the project, this may involve:
QC inspector
Welding inspector
QA/QC engineer
Client inspector
Third-party inspector
Responsible engineering personnel
The technician's role is to accurately report the examination result.
The technician should not independently authorize a repair unless the person's responsibilities and project procedures specifically permit it.
5.10 Step 8 — Nonconformance / Rejection Control
The unacceptable result may lead to a nonconformance record or other controlled disposition.
The documentation may identify:
Component
Weld number
Original NDT report
Indication location
Nature of the nonconformity
Applicable requirement
Proposed disposition
Repair requirements
Responsible approval
The exact terminology varies between quality systems.
The important principle is:
The rejected condition must remain traceable.
5.11 Step 9 — Repair Planning
The welding/QC team determines how the unacceptable condition will be repaired.
Depending on the situation, the repair may involve:
Identifying the affected area.
Removing the unacceptable material.
Preparing the repair area.
Performing the approved repair welding process.
Completing required inspections.
Performing NDT after repair.
Recording the final result.
The repair should be performed according to the applicable approved welding and quality requirements.
5.12 Common Mistake: Starting Repair Without Proper Identification
A repair crew may be told:
"There is a UT indication somewhere around this weld. Grind it out."
This is poor practice.
The repair location should be clearly identified using the project's approved method.
Why?
Because the repair team must know:
Which weld?
Which side?
Which location?
What extent?
What repair instructions apply?
Practical Tip
The repair location should be traceable back to the original NDT indication.
5.13 Step 10 — Repair Is Performed
The repair team removes the unacceptable area according to the approved repair procedure.
After removal, additional inspection may be required to verify that the unacceptable condition has been adequately removed before welding.
The repair weld is then completed according to the applicable welding procedure and project requirements.
The repaired area should remain associated with the original weld identification.
For example:
Original Weld: N-105
Repair: N-105-R1
The exact naming system depends on the project's document-control system.
5.14 Step 11 — Visual Inspection After Repair
Before repeating the original NDT examination, the repaired weld may require visual inspection.
The responsible inspector verifies the repair condition according to the applicable requirements.
Items may include:
Weld profile
Surface condition
Undercut
Surface discontinuities
Repair area
Weld dimensions where required
Identification
General workmanship
If the required visual inspection is satisfactory, the weld can proceed to the required NDT re-examination.
5.15 Step 12 — Re-Examination
Now the repaired weld must be examined again according to the applicable requirements.
This is not an opportunity to ignore the original failure.
The re-examination should be properly identified as a repair/re-examination.
Example:
Component: V-101
Original Weld: N-105
Repair: R1
Re-Examination: UT
Reference: Original NDT Report NDT-2026-00125
This creates a clear chain between the original examination and the re-examination.
5.16 Step 13 — Re-Check Equipment Before Re-Examination
Before performing the re-examination, the technician again verifies the required equipment condition and calibration/verification requirements.
The technician should not assume:
"The instrument was calibrated yesterday, so it is automatically okay."
The applicable procedure determines what verification is required.
5.17 Step 14 — Re-Examine the Repair Area
The technician performs the required examination.
Suppose no unacceptable indication is detected in the repaired area.
The technician evaluates the examination result according to the applicable acceptance requirements.
The result is:
ACCEPTABLE
5.18 Step 15 — Prepare the Re-Examination Report
A separate or revised controlled record may be required depending on the project's document system.
Example:
Original Weld: N-105
Repair: R1
Re-Examination Method: UT
Reference: Original UT Report NDT-2026-00125
Result: ACCEPTABLE
The record should make it clear that this was a re-examination after repair, not the original examination.
5.19 Step 16 — Final Review
The responsible QC/inspection team reviews the documentation.
The complete history should now show:
N-105
↓
Initial UT
↓
Not Acceptable
↓
Repair R1
↓
Visual/required inspection
↓
UT Re-Examination
↓
Acceptable
This provides a traceable inspection history.
5.20 What If the Re-Examination Also Fails?
Repair does not automatically guarantee acceptance.
Suppose the re-examination detects another unacceptable indication.
The workflow becomes:
Initial NDT
↓
Reject
↓
Repair R1
↓
Re-NDT
↓
Reject
↓
Further disposition
↓
Repair R2 if authorized
↓
Re-NDT
↓
Final disposition
Each stage should remain properly documented.
Important
Do not simply overwrite the previous report.
The inspection history should remain traceable according to the project's document-control system.
5.21 Common Mistake: Deleting the Original Rejection
This is a serious documentation mistake.
For example:
Initial report:
N-105 — Not Acceptable
After repair, someone deletes the original report and creates:
N-105 — Acceptable
This removes the inspection history.
Correct Practice
Maintain the original examination record and document the repair and re-examination through the approved process.
The final result can be acceptable while the original rejection remains part of the historical record.
5.22 Common Mistake: Calling the Repaired Weld a New Weld
A repaired section does not automatically become a completely new weld for documentation purposes.
The repair should remain traceable to the original weld.
For example:
N-105 → Repair R1 → Re-NDT
is much better traceability than:
N-200 → New Weld → Acceptable
when N-200 was actually the repaired N-105 weld.
The project's identification system should always be followed.
5.23 Common Mistake: Re-Examining Only Part of the Required Area
A technician may think:
"The repair was only 100 mm, so I'll scan only 100 mm."
That may or may not satisfy the applicable requirements.
The required re-examination extent must come from the applicable code, specification, procedure and project requirements.
Practical Tip
Never determine the re-examination extent based solely on convenience.
5.24 Common Mistake: Changing the Original Report
Another common mistake is modifying the original report after repair.
For example:
Original:
N-105 — NOT ACCEPTABLE
After repair:
N-105 — ACCEPTABLE
without recording the repair and re-examination.
This destroys traceability.
The correct history is:
Initial examination: Not Acceptable → Repair → Re-examination: Acceptable
5.25 Full Site Timeline
Here is the complete scenario in simple form:
08:30 — Inspection Request Received
QC requests UT examination of weld N-105.
08:45 — Identification Verification
Technician verifies vessel, weld number, drawing and procedure.
09:00 — Equipment Verification
Required equipment checks/calibration are completed.
09:15 — UT Examination Begins
Technician examines the weld.
09:40 — Indication Detected
A significant response is identified.
09:50 — Evaluation Completed
The indication is evaluated according to the applicable requirements.
10:00 — Result Declared
The indication does not meet the applicable acceptance criteria.
Result: NOT ACCEPTABLE
10:15 — Report Submitted
Initial NDT report is completed.
Later — Repair Authorized
The responsible team initiates the approved repair process.
Repair Stage
Unacceptable material is removed and the weld is repaired.
Post-Repair Inspection
Required inspection confirms the repair is ready for NDT re-examination.
Re-Examination
UT is performed again according to the applicable requirements.
Final Result
No unacceptable indication is detected.
Result: ACCEPTABLE
Final Documentation
The re-examination record is linked to the original weld and repair history.
5.26 What a Level II Technician Should Never Do
A professional NDT technician should never:
❌ Hide an unacceptable indication.
❌ Change a rejection to acceptance without a valid re-examination.
❌ Delete the original inspection record simply because a repair was successful.
❌ Approve a repair outside their authority.
❌ Use an incorrect acceptance criterion.
❌ Re-examine without following the applicable procedure.
❌ Claim a repaired weld was never previously rejected.
❌ Sign a report for an examination that was not performed.
❌ Backdate an inspection.
❌ Allow production pressure to determine the technical result.
5.27 The Difference Between Repair and Re-Examination
These two activities should not be confused.
Repair
The physical nonconforming condition is corrected.
Re-Examination
NDT is performed again to determine whether the repaired condition satisfies the applicable requirements.
Therefore:
Repair ≠ Acceptance
Only the required subsequent inspection/evaluation and applicable disposition establish the final result.
5.28 Practical Interview Question
Question:
A weld fails UT. The weld is repaired and the repair looks visually acceptable. Can you mark the original UT report as acceptable?
Correct Answer:
No.
The original examination result should remain accurately recorded. The repair and subsequent required re-examination should be documented separately or through the project's controlled reporting system.
Explanation:
A successful repair does not change what was found during the original examination.
Practical Tip:
Remember:
Original result stays original. Repair creates a new inspection event.
5.29 Another Level II Interview Question
Question:
A production supervisor asks you to perform re-UT immediately after grinding a rejected indication. What should you do?
Correct Answer:
Follow the applicable repair and inspection procedure.
Confirm that the repair area is ready for examination and that any required intermediate inspection has been completed before performing the re-examination.
Practical Tip:
Do not let production urgency replace the approved inspection sequence.
5.30 Final Repair & Re-Examination Checklist
Before closing a repaired NDT item, verify:
☐ Original weld identification confirmed.
☐ Original NDT report available.
☐ Rejection/indication properly documented.
☐ Repair area identified.
☐ Repair performed under the applicable approved process.
☐ Required inspection after repair completed.
☐ Re-examination procedure verified.
☐ Equipment verification/calibration completed as required.
☐ Required examination extent completed.
☐ Indications evaluated correctly.
☐ Correct acceptance criteria applied.
☐ Re-examination result recorded.
☐ Original report remains traceable.
☐ Repair record linked to original weld.
☐ Final disposition approved by the responsible authority.
5.31 Final Takeaway
A failed NDT examination is not the end of the inspection process.
It begins a controlled sequence:
Detect → Evaluate → Document → Repair → Re-Examine → Evaluate → Document → Close
The most important principle is traceability.
A professional NDT Level II technician should be able to show the complete history of a weld:
What was found initially, where it was found, what repair was performed, what was re-examined, and what the final result was.
A repair does not erase an inspection history.
It adds another controlled stage to that history.
That is the correct mindset for professional NDT inspection and quality documentation.
Conclusion
A good NDT inspection is not simply about performing a test and recording whether a weld has passed or failed. A professional inspection requires the complete process to be controlled—from reviewing the applicable documents and verifying personnel and equipment, through surface preparation, examination, indication evaluation, reporting, and, when required, repair and re-examination.
The most important lesson is never to treat an NDT indication as an automatic rejection. The indication must be properly evaluated against the applicable procedure, specification, drawing, code, or acceptance criteria. If a relevant indication exceeds the permitted acceptance limits, the repair must be properly documented and the repaired area must be re-examined using the required method and examination extent.
For NDT Level II technicians, inspectors, welding inspectors, and QA/QC professionals, following a systematic inspection checklist can prevent common mistakes such as inspecting the wrong weld, using an incorrect procedure, missing calibration or equipment verification, incorrectly evaluating indications, or submitting incomplete inspection records.
Use this guide as a practical reference during inspection planning and site work, but always follow the approved project procedure, applicable construction code, specification, and acceptance criteria for the actual inspection.
A reliable NDT inspection is one where the examination is technically correct, the indications are properly evaluated, and every important inspection decision can be supported by clear documentation.
Related NDT Quality Hub Guides
Continue your NDT learning with these existing guides on NDT Quality Hub:
ASME Section V vs Section VIII — understand the difference between NDE requirements and construction/acceptance requirements.
ASME Section IX WPS, PQR & WPQ Guide — understand welding procedure and welder qualification documentation.
RT Acceptance Criteria: UW-51 vs UW-52 — learn how radiographic results are evaluated for the applicable ASME Section VIII requirements.
MPT Acceptance Criteria: ASME Section VIII Appendix 6 — understand magnetic-particle indication evaluation.
Top 10 Common Welding Defects in NDT — review common weld discontinuities and their detection methods.
PAUT and TOFD Guides — learn about advanced ultrasonic examination and data recording
- NDT Inspection Report Format — for detailed report preparation and sample report structure.
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