What Does Remote Field Testing (RFT) Mean?
Remote field testing is a nondestructive testing method performed on ferritic materials, which uses alternating current to induce an electromagnetic field. Electric coils are then used to detect flaws and measure material thickness in the part being inspected. While both methods rely on electromagnetism, there are differences between remote field testing and a related method, eddy current testing.
Corrosionpedia Explains Remote Field Testing (RFT)
Remote field testing requires several pieces of equipment to perform the inspection process. A power source and electrical transformer generate the alternating current necessary to perform the inspection. The generated alternating current is then released through an exciting coil that is placed inside the ferritic tubing being inspected. The current is then sent through the pipe length both radially and axially until it is received by a detection unit. The location and size of imperfections and flaws are determined by inspecting the disturbances as the electrical current travels through the object being tested.
Remote field testing can also be used to discover wall loss and changes in wall thickness.
Although remote field testing is similar to eddy current testing, there are several important differences between the two. One notable difference is the frequency of alternating current being used. Remote field testing uses low frequencies, generally less than several hundred hertz. Eddy current testing commonly uses frequencies up to several thousand hertz. Another important difference is the types of flaws that can be detected. Remote field testing can detect flaws on both the inside diameter and outside diameter of ferritic material tubing very well, while eddy current testing is better suited for nonferritic material tubing inspection.