Tubular NDT


Tubular NDT is the application of various technologies to detect anomalies such as corrosion and manufacturing defects in metallic tubes. Tubing can be found in such equipment as boilers and heat exchangers. To carry out an examination in situ, a manhole cover is usually removed to allow a technician access to the tubes. Alternatively, a tube bundle may be removed from a heat-exchanger and transported by forklift to a maintenance area for easier access.
The usual means of examination is to insert some type of probe into the tubes, one at a time, while data is recorded for later interpretation. The technologies listed below are all able to detect defects on the outside of the tube from the inside. The tubes must be clean enough to allow passage of the probe: deposits of debris, rust, or scale may have to be removed by chemicals or pressure washing. In water-tube boilers, the tubes may be examined from the outside when the boiler is shut down, often using ultrasonic testing.

Common methods