SpirALL® Electromagnetic Acoustic Transducer

Electronic Transducer

Designed to enhance inline inspection and give pipeline owners and operators more confidence about inspection results for crack detection, SpirALL® Electromagnetic Acoustic Transducer (EMAT) technology finds cracks (zero width) that magnetic flux leakage-based technology is unable to detect. This includes defects such as stress corrosion cracking, lack-of-fusion, hook cracks, toe cracks, and cracks in dents.

Data from SpirALL EMAT is combined with additional integrity data produced by the various technologies on the Multiple Dataset (MDS) platform. This enables more accurate characterization of pipeline defects, including crack threats and mechanisms, and the identification of interactive threats that would otherwise go undetected with fewer datasets. In addition, combining MDS with SpirALL EMAT data provides pipeline operators with improved comprehensive seam and/or pipe body crack assessment.

Best used for: crack assessment and coating disbondment detection

Key features:

  • Correlation with data from the MDS tool that provides the most comprehensive assessment for crack and crack-like defects
  • Unparalleled signal-to-noise ratio directly improves probability of detection
  • Eliminates false calls for non-critical features with MDS correlation
  • Delivers all pipeline features and anomalies in a single report with MDS
  • Additional crack analysis services
  • Offers detection and sizing of:
    • SCC
    • Lack of fusion/cold welds
    • Hook cracks
    • Toe cracks
    • Coating disbondment
    • Coating damage
    • Surface breaking laminations


  • Why does TDW run its MDS platform prior to an EMAT inspection? Think about the limitations of using only four of your five available senses. We consider EMAT to be a fifth sense: it allows us to improve the overall assessment of the possible defects on a pipeline and differentiate between crack (EMAT) and crack-like (MDS) defects. Additionally, EMAT is used with MDS to look for interactive threats such as dent with a crack, corrosion with a crack, hard spot with a crack, etc.
  • How does SpirAll EMAT technology reduce acoustic signal noise? An obliquely oriented magnetic field that is similar to the design of the SpirALL MFL tool amplifies the acoustic signal inside the pipe wall without increasing the noise.
  • Why is noise in the signal a problem? Noise can cause false or irrelevant data to be erroneously recorded as a defect. By limiting noise, you reduce the likelihood of spending time or money trying to mitigate so-called “ghost” defects. Furthermore, reduced noise in a signal increases your ability to detect the shallower crack depths in the pipeline that would otherwise go undetected.
  • How does EMAT technology detect crack and coating defects in both liquid and gas pipelines? Unlike ultrasonic crack detection (UTCD) sensors, EMAT sensors contact the pipe wall directly to transmit an acoustic wave into the pipe without the requirement of a liquid couplant.