NDT technologies are used to measure material thickness in a wide variety of industries, both for manufacturing quality
control and for in-service monitoring. In many cases a primary advantage of NDT is the ability to precisely measure wall
thickness in situations where access is available to only one side of a test piece, as in a pipe or tank, or where simple
mechanical measurement is impossible or impractical for other reasons, such as part size or access limitations. Ultrasonic
thickness gages can be used on virtually any engineering material, including most metals, plastics, glass, ceramics, rubber,
fiberglass, and composites. Eddy current instruments can be used for measurement of thin layers of conductive material such
as metal aircraft skin or thin-walled metal tubing, and for measurement of the thickness of nonconductive coatings like paint
on conductive substrates.