Guided Wave


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  7. Guided Wave Electro Magnetic Acoustic Transducer (EMAT) Inspections

IRISNDT uses EMAT guided waves to inspect piping for metal loss. More specifically, we use the technique to inspect inaccessible areas such as that under pipe supports. The guided waves can travel in the circumferential or axial direction and are sensitive to thickness changes (corrosion losses) on entire volumes of pipe (equally sensitive to internal and external wall loss). To assess the location and extent of corrosion damage, IRISNDT uses EMAT guided wave ultrasonic wave arrival time (velocity change) and amplitude information.


  • Detecting touch/contact point corrosion
  • Detecting corrosion under supports
  • Identifying soil to air interface corrosion
  • Detecting corrosion, erosion and cracking in ground piping
  • Detecting corrosion, erosion and flaws in furnace tubes


  • This dry and non-contact method does not require an acoustic couplant
  • It allows up to 2.5 mm (0.1 inch) lift-off
  • Allows coverage of up to 1 meter (3.3 feet) with short range guided wave
  • Allows for the inspection of physically inaccessible areas
  • Allows real time analysis and storage of inspection data
  • The data is represented in A, B and C-scans)
  • The high frequency guided wave results in better accuracy and resolution than the low frequency guided wave (long range guided waves)
  • Applicable to pipe diameters greater than 50 mm (2 inch) using axial guided waves, and pipe diameters ranging from 150 mm (6 inch) to 600 mm (24 inch) using circumferential guided waves.
  • Can be used at up to 200 °C (392 °F)


  • Insulation removal at the test location is needed
  • Surface cleaning at EMAT probe locations is recommended

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Learn more about how IRISNDT applies Guided Wave Electro Magnetic Acoustic Transducer (EMAT) Inspections