Thermography / Infrared Testing (IRT)
Thermography uses an infrared camera to map surface temperature patterns; subsurface defects, moisture, missing insulation, electrical hot spots, and CUI alter heat flow and create detectable thermal signatures.
Definition
Thermographic testing (infrared testing, IRT) uses a calibrated infrared camera to capture surface temperature distributions. Subsurface anomalies disturb the heat flow and produce thermal contrasts that the camera resolves as hot or cold spots.
Technical Context
Two modes are common: passive (observing natural temperature differences, e.g. on energized switchgear) and active (heating the surface and watching the cooling pattern). Active thermography is the basis for composite delamination detection and adhesive bond inspection.
When It Is Used
- Electrical switchgear and motor surveys
- Moisture and CUI screening on insulated piping
- Composite delamination detection
- Building envelope and refractory inspection
Related Standards
ASTM E1934, ISO 18434, ASNT SNT-TC-1A for IR personnel.
How it works
Infrared imaging of surface temperature as an NDT method: passive thermography reads existing thermal patterns (electrical faults, refractory loss, blocked tubes); active thermography injects heat and watches the decay, where subsurface flaws disturb the flow.
What it finds
Delaminations and voids in composites, corrosion under insulation indications via wet-insulation signatures, refractory degradation through shell temperature, electrical and rotating-equipment hot spots.
What it will not find
Depth: sensitivity collapses quickly with flaw depth in conductive materials. Emissivity variation, reflections and wind rewrite surface temperatures — a shiny surface is a mirror, not a thermometer.
Governing codes and standards
ASNT recognises IR/thermal testing as a method with its own certification track; ISO 18434 covers machinery thermography; ASTM has practice standards for composites (E2582).
Where it goes wrong
Reading absolute temperatures off low-emissivity surfaces without correction. The camera reports a number confidently; on bare metal that number is dominated by reflected sky and surroundings, not the part.
Where Thermography / Infrared Testing fits in an inspection programme
A term is only useful when it connects to a decision. Thermography / Infrared Testing appears in written procedures, in technique sheets, and in the records an owner or accreditation body reviews afterwards — which means the way it is defined in your documentation has to match the way it is applied on site. Where the two drift apart, audits find it. Atlantis writes and reviews procedures against the governing codes, trains inspection personnel to apply them, and builds the record-keeping that makes the evidence retrievable years later. Procedure development and code consulting · NDT training and certification · Ask us about your programme.
Related terms
- Corrosion Under Insulation (CUI) — Corrosion under insulation is external corrosion of carbon and low-alloy steel piping and vessels hidden beneath thermal insulation, caused by water ingress that accelerates corrosion in the 60–175 °C temperature range.
- Acoustic Emission Testing (AE) — Acoustic Emission (AE) is a passive NDT method that detects transient elastic stress waves emitted by active discontinuities such as growing cracks, plastic deformation, or leaks, using sensors mounted on the component during loading.
Further reading
thermography and infrared inspection techniques
More method terms
Ultrasonic Testing · Radiographic Testing · Magnetic Particle Testing · Penetrant Testing · Eddy Current Testing · Visual Testing · Leak Testing · Microwave Testing · Phased Array Ultrasonic Testing · Time-of-Flight Diffraction
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.