Eddy Current Testing

Eddy current testing (ECT) in Dubai and Abu Dhabi — electromagnetic NDT for surface and near-surface cracks through paint and coatings, conductivity measurement, material sorting and coating thickness, carried out by ISO 17020 accredited and ADNOC approved inspectors. Last reviewed: August 2026.

Eddy current testing detects cracks and material changes using electromagnetic induction, with no physical contact required between the probe and the metal itself. That single characteristic is what makes it valuable: it finds surface and near-surface cracks straight through paint, galvanising and other coatings, on components where removing the finish would cost more than the inspection.

How it works

A coil carrying alternating current generates a changing magnetic field. Held against a conductive surface, that field induces circulating eddy currents in the material. Anything that disturbs their flow — a crack, a change in conductivity, a variation in magnetic permeability, a change in thickness — alters the impedance seen by the coil, and the resulting shift in phase and amplitude is measured against reference values from calibration standards. Test frequencies typically range from 100 Hz to 6 MHz depending on material conductivity and required penetration depth. Interpretation is comparative, which is why the calibration blocks and the technician's judgement matter more in this method than in most.

Crack detection through coatings

Magnetic particle and penetrant inspection both require the coating to be removed, the test performed, and the surface recoated. On a painted crane boom, a structural weld or a coated pressure vessel, that sequence dominates the cost and the downtime — and it introduces a new coating whose quality then has to be verified.

Eddy current works through the coating. Lift-off is compensated in the technique, and detection of surface-breaking cracks remains reliable at the coating thicknesses normally found in service — typically up to 2 mm of non-conductive coating. For crane owners this is the difference between an inspection that takes a shift and a programme that takes the equipment out of service for a week. It applies equally to concrete pumping equipment, access platforms, structural steelwork and aerospace components where the protective finish is part of the certification and cannot be disturbed.

Other applications

• Electrical conductivity measurement — expressed in %IACS, used to verify alloy condition and identify material
• Heat treatment verification — confirming that solution treatment, ageing or annealing has produced the intended condition in aluminium and titanium alloys
• Heat damage assessment — detecting where aluminium has been overheated, for example after a fire or an in-service thermal event
• Material sorting — separating mixed batches by alloy, temper, hardness or strength where documentation has been lost
• Coating thickness measurement — both conductive and non-conductive coatings on metallic substrates, to ASTM E376
• Thickness measurement of thin sections where access is available from one side only

Standards applied

• ASME Boiler and Pressure Vessel Code, Section V, Article 8 — eddy current examination
• ISO 15549 — general principles for eddy current testing
• ASTM E1004 — determination of electrical conductivity by the electromagnetic method
• ASTM E376 — coating thickness measurement by magnetic-field or eddy-current methods
• Client, project and manufacturer specifications, and aerospace maintenance manual procedures where these govern

Personnel qualification

Eddy current demands more of the technician than any other surface method. The signal is an impedance response, not a visible indication, and distinguishing a crack from an edge effect, a geometry change or a permeability variation depends on the operator's experience with that component and that material. ITMAD's eddy current work is carried out by technicians qualified to ISO 9712 and ASNT SNT-TC-1A Level II, with NAS 410 qualification for aerospace components and Level III oversight of procedures and technique validation.

Limitations

The method applies only to electrically conductive materials. Penetration depth is limited and reduces as frequency, conductivity and permeability rise — standard ECT penetration is typically 1–6 mm depending on material and frequency. Ferromagnetic materials produce permeability variations that can mask genuine indications and require careful technique selection. Complex geometry, edges and fasteners generate signals that must be distinguished from defects. Reference standards representative of the component and coating are essential; without them the results are not interpretable. Where eddy current is the wrong method for the defect you need to find, we will say so.

Typical components examined

• Crane booms, jibs and lattice sections
• Structural welds under paint
• Lifting equipment hooks and pins
• Concrete pump booms and outriggers
• Aircraft skin, frames and fastener holes
• Turbine and engine components
• Pressure vessel and pipework welds
• Non-ferrous castings and forgings
• Fastener holes and bolt bores
• Aluminium structures and assemblies

Accreditation and approvals

ITMAD is accredited to ISO/IEC 17020 as an inspection body, is an ADNOC approved inspection contractor, and is listed on the Abu Dhabi City Municipality register of Approved Third Party Inspection Bodies. Certificates are issued in the format required by Dubai Municipality and the Dubai free zone authorities. Eddy current testing is carried out across Dubai, Abu Dhabi, Sharjah and the northern Emirates, at your site, offshore, in fabrication yards or at ITMAD premises.

What you receive

• A report identifying the components examined and the areas covered
• Equipment, probe type and frequency used, and the reference standards calibrated against
• Coating thickness present at the time of examination, where relevant
• Indications recorded with location, response and interpretation
• Accept or reject status against the applicable acceptance criteria
• Conductivity or thickness values where these are the purpose of the examination
• Technician qualification level and certification reference