Non-destructive testing, or NDT, helps inspect critical components without cutting them open, damaging them or removing them from service unnecessarily.

That matters when the component is part of a machine, lift, boom, truck, structure or production asset that needs to remain safe and reliable.

The original JM Test article focuses on NDT for critical pins, welds, fasteners and other components identified by the manufacturer as critical structural components. It also notes that NDT can be performed on aerial lift devices, digger derricks and other tracked or wheeled units with critical components.

For Canadian utilities, contractors, municipalities, industrial plants, mines, telecom crews and fleet owners, the practical question is simple:

Can the component be inspected for cracks, wear, corrosion or internal degradation without destroying it?

That is what NDT is designed to support.

What Is Non-Destructive Testing?

Non-destructive testing is a group of inspection methods used to evaluate a material, component or assembly without causing damage that would prevent continued use.

NDT may be used to inspect:

• Critical pins
• Welds
• Fasteners
• Boom structures
• Turntable bearings
• Structural components
• Pressure equipment
• Piping
• Castings
• Forgings
• Shafts
• Hooks
• Lifting equipment
• Heavy equipment
• Aerial devices
• Digger derricks
• Utility equipment

NDT does not mean the equipment is automatically safe.

It means specific inspection methods were used to look for specific types of discontinuities, defects, degradation or wear.

The value of NDT depends on the right method, qualified personnel, correct procedure, clean surface condition, suitable access, accurate reporting and proper interpretation.

Why NDT Matters

Many critical components fail from problems that begin small.

A crack, wear pattern, corrosion area, internal flaw or bearing movement may not be obvious during a routine walkaround.

NDT can help identify these issues before they lead to:

• Structural failure
• Equipment downtime
• Safety incidents
• Failed inspections
• Costly repairs
• Premature replacement
• Jobsite delays
• Warranty or compliance issues
• Loss of confidence in equipment condition

The source article frames NDT as a way to inspect for sub-surface degradation without damaging the components on the truck.

That is especially important for aerial devices and digger derricks because workers may be positioned above ground, near utilities or in environments where structural failure could be serious.

Canadian NDT Certification Context

For Canadian content, NDT should be tied to Canadian personnel certification and the applicable equipment standard, owner procedure or manufacturer requirement.

Natural Resources Canada manages the national NDT certification programme in Canada. NRCan states that the National Non-Destructive Testing Certification Body issues NDT certifications under CAN/CGSB-48.9712-2022, which is aligned with ISO 9712, effective April 1, 2024.

ISO 9712:2021 specifies requirements for the qualification and certification of personnel who perform industrial NDT in methods including magnetic testing, penetrant testing, radiographic testing, ultrasonic testing, thermographic testing, eddy current testing, acoustic emission testing, leak testing and visual testing.

For Canadian projects, confirm:

• Required NDT method
• Required certification level
• Required sector
• Applicable CAN/CGSB-48.9712 requirement
• Manufacturer inspection requirement
• Owner inspection programme
• Provincial or territorial rules
• Equipment standard
• Acceptance criteria
• Report format
• Reinspection interval

Do not assume that any technician with inspection experience is qualified for every NDT method or every equipment type.

NDT for Aerial Devices and Digger Derricks

The source article specifically mentions aerial lift devices, digger derricks and other tracked or wheeled units with manufacturer-identified critical components.

These assets may include:

• Bucket trucks
• Vehicle-mounted aerial devices
• Digger derricks
• Line trucks
• Utility boom equipment
• Tracked aerial units
• Wheeled access units
• Equipment with rotation bearings
• Equipment with critical pins and welds

In Canada, vehicle-mounted aerial devices are commonly tied to CSA C225. CSA C225:2020 is a National Standard of Canada for vehicle-mounted aerial devices and establishes criteria for design, manufacture, testing, inspection, installation, maintenance, use and operation of these devices.

For Canadian pages, avoid saying NDT alone satisfies every aerial device requirement.

NDT is one part of the inspection and maintenance programme. Electrical testing, dielectric testing, visual inspection, mechanical inspection, manufacturer instructions, CSA C225 requirements, provincial or territorial rules and owner procedures may also apply.

What NDT Can Find

NDT may help identify:

• Cracks
• Corrosion
• Wall thinning
• Wear
• Pitting
• Weld defects
• Lack of fusion
• Surface-breaking discontinuities
• Subsurface flaws
• Internal degradation
• Bearing wear
• Excessive movement
• Fatigue-related damage
• Damage from overload
• Damage from impact
• Manufacturing defects
• In-service deterioration

The exact findings depend on the method used.

No single NDT method finds everything.

That is why a good inspection plan starts with the defect you are trying to detect.

Visual Examination, or VT

Visual examination is usually the first step.

The source article says visual examination provides a more in-depth examination of critical pins, welds and fasteners for signs of extensive wear, corrosion, cracking and other defects.

Visual testing can help identify:

• Obvious cracks
• Corrosion
• Wear
• Missing hardware
• Loose fasteners
• Deformation
• Impact damage
• Paint cracking
• Weld surface concerns
• Misalignment
• Signs of movement
• Surface contamination
• Missing retainers
• Damaged locking devices

Visual examination is simple, but it is not casual.

It should be done with suitable access, lighting, surface condition, inspection criteria and documentation.

A visual check may also determine whether another NDT method is needed.

Ultrasonic Thickness Testing, or UT

Ultrasonic testing uses sound waves to evaluate thickness or internal conditions.

The source article describes ultrasonic thickness testing as an inspection method used to determine cracking and other degradation of critical pins in the boom structure. It explains that an ultrasonic wave is sent from the test instrument and the measured distance is displayed on the instrument screen.

In practical terms, UT can help inspect:

• Critical pins
• Boom components
• Structural members
• Pressure equipment
• Piping
• Tanks
• Wall thickness
• Corrosion loss
• Internal degradation
• Material loss

For pins and boom structures, UT can help identify whether the returned signal suggests a possible issue compared with expected material thickness.

UT results depend on:

• Correct probe selection
• Proper couplant
• Surface preparation
• Material type
• Calibration block or reference standard
• Geometry of the component
• Access to the test surface
• Technician skill
• Procedure and acceptance criteria

A UT thickness reading should not be interpreted without knowing the component, material and inspection requirement.

Magnetic Particle Testing, or MT

Magnetic particle testing is used on ferromagnetic materials.

The source article explains that magnetic particles are applied to a suspicious weld, a magnetic field is applied, and the particles accumulate around cracks or discontinuities that may be present.

MT can be useful for:

• Weld inspection
• Surface cracks
• Slightly subsurface discontinuities
• Critical ferromagnetic components
• Pins and structural components where applicable
• Follow-up after visual examination

MT is not suitable for every material.

It generally applies to ferromagnetic materials such as certain steels. It is not used the same way on aluminium, austenitic stainless steel or non-magnetic materials.

Before using MT, confirm:

• Material type
• Surface condition
• Magnetization method
• Particle type
• Lighting requirement
• Demagnetization requirement
• Acceptance criteria
• Technician certification
• Report requirements

Dye Penetrant Testing, or PT

Dye penetrant testing is used to help detect surface-breaking defects.

The source article describes dye penetrant testing as another NDT method used to further confirm cracks or discontinuities in a weld. It also notes that paint removal may be required from the surface.

PT may be used on:

• Welds
• Non-magnetic materials
• Machined parts
• Castings
• Forgings
• Surface-breaking cracks
• Components where MT is not suitable

PT usually requires:

• Surface cleaning
• Penetrant application
• Dwell time
• Excess penetrant removal
• Developer application
• Inspection under the required lighting conditions
• Final cleaning
• Documentation

PT only finds defects open to the surface.

It will not find fully internal flaws that do not reach the surface.

Rotation Bearing Deflection

Rotation bearing deflection is used to track bearing wear over time.

The source article explains that rotation bearing deflection is used to determine the amount of wear on turntable bearings over time, and that worn bearings may lead to loose movement, excessive backlash, excessive wear, permanent deformation and early bearing failure.

This can be important for:

• Aerial devices
• Digger derricks
• Cranes
• Turntable-mounted equipment
• Utility equipment
• Rotating boom equipment

Bearing deflection checks can help identify whether movement is increasing compared with previous readings.

That is why baseline records matter.

A single reading may be useful, but trend data is stronger.

Surface vs Subsurface Testing

Different NDT methods look for different problems.

The wrong method can create false confidence.

A component can pass one type of inspection and still have a defect that requires a different method to detect.

When NDT Should Be Considered

NDT may be useful when:

• The manufacturer identifies a critical structural component
• The equipment is due for periodic inspection
• A boom, pin, weld or bearing is safety-critical
• Equipment has been overloaded
• Equipment was involved in an incident
• There is visible cracking or corrosion
• There is unusual movement or backlash
• The equipment has high service hours
• The equipment operates in harsh environments
• A repair was completed
• A weld needs verification
• A customer or owner requires inspection records
• A regulator or AHJ requires specific inspection
• Previous records show a developing trend
• Equipment is being purchased used
• Equipment is returning to service after storage

For aerial devices and digger derricks, the manufacturer’s instructions and applicable equipment standard should drive the inspection plan.

NDT Does Not Replace Routine Inspection

NDT is not a replacement for daily, pre-use or periodic visual inspections.

It should work alongside:

• Operator inspections
• Maintenance inspections
• Functional testing
• Lubrication checks
• Dielectric testing where applicable
• Hydraulic checks
• Fastener checks
• Structural inspections
• Manufacturer service bulletins
• Owner maintenance records

A component may pass an NDT inspection but still have other mechanical, hydraulic, electrical or operational issues.

The inspection programme should look at the full asset, not only one test result.

Canadian Safety and Regulatory Considerations

Canadian NDT work should be planned around the asset, method and hazard.

Depending on the inspection, safety considerations may include:

• Working at height
• Boom movement
• Stored hydraulic energy
• Pinch points
• Suspended loads
• Traffic control
• Lockout
• Electrical hazards
• Sharp edges
• Chemical exposure from penetrants
• Magnetic fields during MT
• Radiation hazards during RT
• Confined spaces
• Pressure systems
• Site permits
• Manufacturer procedures
• Provincial or territorial OHS requirements

If radiographic testing is involved, additional controls apply. The Canadian Nuclear Safety Commission states that industrial radiography is regulated by the CNSC, uses high-activity sealed radioactive sources for NDT, and is considered a high-risk activity because these sources can deliver high radiation doses. CNSC also states that exposure devices and related accessories must be certified before they can be licensed for use in Canada.

The JM Test source article does not focus on radiographic testing, so do not add radiography service claims unless the Canadian service scope is confirmed.

What to Confirm Before Scheduling NDT

Before booking NDT for aerial devices, digger derricks or other critical assets, confirm:

• Equipment type
• Manufacturer
• Model
• Serial number
• Year
• Asset ID
• Component to be inspected
• Manufacturer-defined critical components
• Required NDT method
• Applicable standard
• Inspection interval
• Certification requirement
• Surface preparation requirement
• Whether paint removal is allowed
• Whether the equipment must be out of service
• Access requirements
• Safety permits
• Lockout requirements
• Prior inspection reports
• Repair history
• Incident history
• Acceptance criteria
• Report format
• Follow-up process if a defect is found

The inspection should be planned before the technician arrives.

Most delays happen when access, records, acceptance criteria or equipment status are unclear.

What Should Be Included in an NDT Report?

A useful NDT report should include:

• Customer name
• Site location
• Equipment type
• Manufacturer
• Model
• Serial number
• Asset ID
• Component inspected
• Inspection date
• Inspection method
• Technician name
• Technician certification
• Certification level and method
• Procedure used
• Acceptance criteria
• Surface condition
• Areas inspected
• Instrument used where applicable
• Instrument serial number
• Calibration or verification status where applicable
• Test results
• Indications found
• Disposition of findings
• Photos where useful
• Sketches or location references
• Limitations of inspection
• Recommendations
• Next inspection interval where applicable

A report should make the finding understandable to the owner, maintenance team, inspector and future technician.

NDT for Critical Pins

Critical pins can wear, crack or degrade under repeated load.

NDT may be used to check:

• Pin diameter condition
• Surface damage
• Cracking
• Internal discontinuities
• Corrosion
• Wear areas
• Fit-up concerns
• Signs of overload

The source article specifically mentions ultrasonic thickness testing for critical pins in the boom structure. It explains that a shorter returned signal compared with the expected overall thickness can help the technician identify a potential issue within the pin.

For Canadian copy, avoid saying UT will find every possible pin defect.

Use “can help identify” and tie final decisions to the inspection procedure and acceptance criteria.

NDT for Welds

Welds may be inspected visually first, then followed with MT or PT if the weld is suspicious or if the procedure requires it.

NDT may look for:

• Cracking
• Porosity
• Undercut
• Lack of fusion
• Surface-breaking defects
• Near-surface defects
• Corrosion at or near welds
• Repair quality issues

The source article describes MT and PT as follow-up methods for suspicious welds after visual examination.

For Canadian projects, weld inspection requirements should be checked against the applicable equipment standard, welding code, owner specification, manufacturer procedure and inspector qualification requirement.

NDT for Fasteners

Fasteners in critical structures should not be ignored.

NDT and detailed inspection may help identify:

• Cracking
• Corrosion
• Stretching
• Thread damage
• Missing or damaged locking features
• Fatigue indications
• Wear
• Improper seating
• Movement
• Deformation

The source article includes fasteners in the components examined during visual testing.

Fastener inspection should consider both the fastener and the joint.

A good fastener in a damaged joint may still be a problem.

NDT for Rotation Bearings

Rotation bearings support movement and load transfer in rotating equipment.

Over time, wear can show up as looseness, backlash or increasing deflection.

The source article explains that rotation bearing deflection helps determine bearing wear over time and can track degradation. It warns that unresolved excessive wear can lead to permanent deformation and early bearing failure.

For fleets, the best practice is to keep consistent records.

Track:

• Date
• Equipment ID
• Test setup
• Bearing position
• Measured deflection
• Previous readings
• Change over time
• Technician notes
• Corrective action

Trend matters more than one isolated number.

Canadian Industries That Use NDT

NDT is useful across Canadian sectors where equipment failure can create safety, downtime or compliance risk.

Common applications include:

Utilities

Bucket trucks, digger derricks, booms, pins, welds and rotation bearings may need inspection as part of fleet maintenance.

Telecom and Line Work

Aerial devices and utility trucks used for overhead work need reliable structural condition.

Mining

Heavy equipment, lifting equipment, structural components and critical pins may require inspection in harsh operating conditions.

Oil and Gas

Piping, pressure equipment, welds, structural supports, lifting assets and rotating equipment may require NDT depending on the asset and inspection programme.

Manufacturing

NDT may be used for quality control, weld inspection, pressure equipment, machine components and maintenance troubleshooting.

Transportation

Rail, fleet, aviation, marine and heavy transport assets may require NDT under applicable maintenance programmes.

Municipal and Public Works

Municipal fleets, aerial units, bridges, equipment and structural assets may use NDT for safety and asset management.

NRCan has described NDT as helping ensure the integrity of safety-critical components in applications such as aircraft, boilers and pressure vessels, bridges, buildings, cranes, heavy equipment, nuclear reactors and pipelines.

Equipment and Calibration Considerations

Some NDT methods depend on test equipment.

Examples include:

• Ultrasonic thickness gauges
• UT flaw detectors
• Probes and transducers
• Calibration blocks
• Magnetic yokes
• Light meters
• UV lamps
• Coating thickness gauges
• Borescopes
• Measurement tools
• Bearing deflection tools
• Data collection tools

JM Test Canada’s calibration services page lists ultrasonic thickness gauges under mechanical and dimensional calibration services. It also lists onsite and mobile calibration services, QR-coded certificates, traceable certificates, calibration stickers, as-found/as-left data and electronic records.

JM Test Canada’s onsite page also lists ultrasonic thickness among onsite calibration categories.

For the Canadian NDT page, keep the service claim careful:

JM Test Systems Canada can support inspection and test-equipment needs where available, including calibration support for ultrasonic thickness equipment. Confirm whether NDT inspection services, specific instruments, accessories, calibration certificates and onsite support are currently available in Canada before booking.

Common NDT Mistakes to Avoid

Treating NDT as One Test

NDT is not one method. Visual, ultrasonic, magnetic particle, dye penetrant and other methods answer different questions.

Using the Wrong Method for the Defect

PT can find surface-breaking defects, but it will not find fully internal flaws. MT generally applies to ferromagnetic materials. UT requires correct setup and interpretation.

Ignoring Manufacturer Critical Components

The source article focuses on components identified by the manufacturer as critical structural components.
Do not build the inspection plan only from guesswork.

Inspecting Without Acceptance Criteria

A report is weak if it says “indication found” but does not state what criteria were used to accept or reject the component.

Not Checking Technician Certification

In Canada, confirm the required CAN/CGSB-48.9712 certification method, level and sector where applicable. NRCan manages Canada’s national NDT certification programme.

Forgetting Surface Preparation

Paint, rust, grease, dirt and coatings can affect visual, magnetic particle and penetrant testing.

Not Keeping Baseline Records

Bearing deflection, UT readings and recurring component inspections are more useful when compared over time.

Treating NDT as a Repair Decision by Itself

NDT provides inspection information. Repair, replacement or return-to-service decisions should follow the applicable standard, manufacturer instructions, engineering review, owner procedure and acceptance criteria.

Practical Takeaway

Non-destructive testing helps inspect critical components without destroying them.

For aerial devices, digger derricks, utility trucks and other critical equipment, NDT can help evaluate pins, welds, fasteners, boom structures and rotation bearings for wear, cracking, corrosion, degradation and other concerns.

The source JM Test article highlights five practical areas: visual examination, ultrasonic thickness testing, magnetic particle testing, dye penetrant testing and rotation bearing deflection.

For Canadian teams, the key is to match the method to the component and requirement.

That means confirming:

• Manufacturer-defined critical components
• Applicable equipment standard
• Required NDT method
• Technician certification
• Acceptance criteria
• Safety controls
• Inspection interval
• Report format
• Follow-up action
• Canadian service and equipment availability

JM Test Systems Canada can support Canadian customers with test equipment, calibration services and onsite support where available. Confirm current NDT-related service availability, ultrasonic thickness calibration support, equipment rental or sales options, technician requirements, certificate format and turnaround time before booking.