Global Remote Integrated Access Solutions

Alternate Current Field Measurement

ACFM is an electromagnetic detection and sizing of surface breaking cracks, particularly suited for inspecting painted and welded structures. An alternating current is induced into the area of inspection using an ACFM probe. In ideal conditions, a uniform magnetic field is produced by the alternating current. Any defect or discontinuity would force the magnetic field lines to change course and a non-uniform field is formed . The sensors in the ACFM probe measure these field variations and relate it to the defect size. The system software allows crack depth and length measurement in real-time.

The ACFM equipment has high portability, which enables Global Remote crew to inspect most difficult to access areas through rope access very easily and this promotes its wide application in the industry.


  • Can be performed through coating (strictly adhered coating)
  • Eliminate extensive cleaning
  • Can be performed with minor scaling & debris
  • Indications can be sized in depth and length
  • High temperature application
  • Permanent data records and offline analysis
  • More precise than conventional methods


  • Detects defect sized >5mm-10mm long and 0.5mm deep
  • Structural Welds (Platforms & Drilling Rigs)
  • Offshore Cranes
  • Cooling Towers
  • Storage Tanks
  • Pressure vessels
  • Short sections are not recommended