What Is IRIS?
The Internal Rotating Inspection System (IRIS) is an ultrasonic tube inspection technique in
which a small immersion transducer, rotating at high speed inside a water-filled tube bore,
directs a focused ultrasonic beam radially outward against the tube wall. The reflected pulse
echo signal from the inner and outer tube surfaces provides a direct, accurate measurement of
wall thickness at each rotational position — producing a continuous helical scan of the full tube
wall as the probe advances through the tube.
Unlike eddy current techniques — which provide electromagnetic signals requiring analyst
interpretation — IRIS provides direct wall thickness measurements with ultrasonic precision.
This makes IRIS the technique of choice where accurate remaining wall quantification is
required for fitness-for-service calculations, or where the tube material makes ECT or RFET less
effective.
Key characteristics:
- Applicable to ferrous and non-ferrous tubes — carbon steel, stainless steel, titanium,
copper alloys
- Direct, quantitative wall thickness measurement — not amplitude-based estimation
- High-resolution C-scan image of tube wall condition
- Detection of pitting, erosion, corrosion, and cracking with sizing accuracy
- Requires water-filled tube bore — flooding preparation necessary before inspection