Internal Rotary Inspection System (IRIS)

IRIS is an ultrasonic tube-inspection technique in which a water-driven rotating mirror inside the tube directs an ultrasonic beam radially outward, producing a high-resolution image of wall thickness and ID/OD pitting.

Definition

IRIS is an immersion ultrasonic technique for heat-exchanger tube inspection. A probe pushed through the tube contains a rotating mirror driven by water flow; the mirror reflects a focused ultrasonic pulse perpendicular to the tube wall. The reflected echoes give a precise wall-thickness map of the entire tube.

Technical Context

IRIS provides absolute thickness data — superior to eddy current for non-ferromagnetic and ferromagnetic tubes alike — but is slower. It is often used to confirm and quantify anomalies found by faster ECT screening.

When It Is Used

Heat-exchanger tube wall thickness measurement
Pitting and ID/OD corrosion quantification
Confirmation of ECT or RFT findings

Related terms

Eddy Current Testing (ET) — Eddy Current Testing (ET) is an electromagnetic NDT method that induces circulating currents in conductive materials using an AC coil; changes in coil impedance reveal surface and near-surface defects, conductivity variations, and coating thickness.
Ultrasonic Testing (UT) — Ultrasonic Testing (UT) is an NDT method that uses high-frequency sound waves (typically 0.5–25 MHz) to detect internal flaws and measure thickness in metals, plastics, and composites by analyzing reflected echoes from a transducer.
Heat Exchanger — A heat exchanger is a pressure vessel that transfers heat between two fluid streams, with the shell-and-tube configuration the most common in refineries, chemical plants, and power generation, inspected primarily by tube ET/IRIS and shell-side UT.

More method terms

Radiographic Testing · Magnetic Particle Testing · Penetrant Testing · Visual Testing · Acoustic Emission Testing · Leak Testing · Thermography / Infrared Testing · Microwave Testing · Phased Array Ultrasonic Testing · Time-of-Flight Diffraction

Where this comes up in practice

Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.

Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.