Internal rotary inspection system (IRIS) is an ultrasonic method for the nondestructive testing of pipes and tubes. The IRIS probe is inserted into a tube that is flooded with water, and the probe is pulled out slowly as the data is displayed and recorded.

This method is employed for inspecting tubes or pipes with small to medium diameters. IRIS operates by leveraging the principles of ultrasonics and using a probe capable of emitting and receiving ultrasonic waves. The tube-shaped probe rotates inside the pipe and is examined during the process.

IRIS relies on a transducer to generate an ultrasonic pulse parallel to the axis of the tube under test. It also relies on a rotating mirror that directs the ultrasonic wave into the tube wall. The mirror is driven by a small turbine powered by the pressure of water pumped into the tube.