• Field-proven and commonly used in boilers, heat exchangers, and fin-fan tubes. • Often used as a back-up to electromagnetic examination of tubes, to verify calibration and accuracy. Especially useful as a follow-up to
remote field testing due to the full sensitivity near tube support structures provided by IRIS. • The IRIS probe must be moved very slowly (approximately 1 inch per second, or 2.5 cm/s), but it produces very accurate results (wall thickness measurements typically accurate to within 0.005 inch, or 0.13 mm). • Before the examination, tubes must be cleaned on the inside to bare metal. • A supply of clean water is needed, typically at a pressure of 60 psi, or 0.4 MPa. Dirt or debris in the water may cause the turbine to jam. • Works for tube diameters of and up. Special centralizing devices are needed for larger diameters. • Works in metal or plastic tubes. • Through-holes are difficult to detect by using this method. • Operates at temperatures above freezing. • Can pass bends, but will not detect defects in bends. • Not sensitive to cracks aligned with tube radius. ==References==