Remote Field Testing (RFT) is one of the several electromagnetic testing methods commonly employed in the field of non-destructive testing. RFT may also referred to as RFEC (Remote Field Eddy Current) or RFET (Remote Field Electromagnetic Technique). RFT is primarily used to inspect ferromagnetic tubing since conventional ECT have difficulty in inspecting the full thickness of the tube wall due to the strong skin effect in ferromagnetic materials.

Near Field Testing (NFT) technology is a rapid and cost-effective solution intended specifically for fin-fan carbon-steel tubing inspection. This technology relies on a simple driver-pickup eddy current probe design providing very simple signal analysis. NFT is specifically suited to the detection of internal corrosion, erosion or pitting in carbon steel tubing. The NFT probes measure lift-off or ‘fill factor’ and convert it to amplitude-based signals. Because eddy-current penetration is limited to the inner surface of the tube, NFT probes are not affected by the fin geometry on the outside of the tube.

The conventional ECT faces major limitations with respect to detection & sizing of circumferential cracking and extent of volumetric flaws in tubular. Rotating probes is a solution but it reduces the inspection speed. Therefore Eddy Current Array (ECA) along with bobbin probe technology is the solution to perform high speed inspection in a single pass.

Magnetic Flux Leakage (MFL) uses a powerful magnets to magnetize the conductive material under test where a magnetic field is created around defects like corrosion or material loss. The magnetic field induced in the part saturates it until it can no longer hold any more flux. The flux overflows and leaks out of the pipe wall and strategically placed sensors can accurately measure the three-dimensional vector of the leakage field. Because magnetic flux leakage is a vector and that a sensor can only measure one direction, any given probe must have three sensors to accurately measure the axial, radial, and circumferential components of an MFL signal.

Internal Rotary Inspection System (IRIS) is an ultrasonic method for testing of pipes and tubes. The ultrasonic beam allows detection of metal loss from the inside and outside of the tube wall. It is a fairly sensitive technique. The sensitivity achieved will depend on tube dimensions and tube cleanliness. Both ferromagnetic and non-ferromagnetic tubes can be inspected. A three dimensional picture of the defect is obtained, thus the defect profile and its depth is provided. Interpretation of results is easier than in the other techniques