In 2008, stennis contracted irisndt INC. Which at that time was called matrix inspection and engineering now irisndt INC. To perform guided wave ultrasound inspection (GUL) of pipes in valve pits. The…

In 2008, stennis contracted irisndt INC. Which at that time was called matrix inspection and engineering now irisndt INC. To perform guided wave ultrasound inspection (GUL) of pipes in valve pits. The pipe penetrated the cement wall and stennis space center was interested in determining the integrity of the concrete to pipe interface. To do this, irisndt tested a sample pipe with known defects at the space center to demonstrate the capabilities of the GUL technique to remotely detect, locate, and classify the relative severity of known defects on that mock up sample that was provided by stennis space center (SSC). The trial was successful in detecting and assessing the relative severity of the known indications. The work then was carried out on piping in valve pits successfully guided wave ultrasound GUL was developed in the 1990S and has taken off as a viable screening tool for the inspection of long length of pipe. A ring of piezoelectric probes is attached to the pipe. The ring generates a torsional wave that will propagate in the pipe. Symmetrical features such as welds will produce symmetrical reflectors. Asymmetrical features such as corrosion; nozzle, drain, vent, etc. Will produce reflectors, but will also generate a mode converted flexural wave. The ring will detect all the returned signals and display them in an a scan and c scan presentation. This technology has been effective in detecting CUI corrosion under insulation with minimum disturbance to the insulation. GUL also proved effective in contact point corrosion at pipe supports road crossings, buried pipe and cased pipe. Numerous tests have been performed and technology has evolved to confidently classify wall loss due to corrosion or erosion in three different categories CAT 1 severe greater than 50 percent wall loss CAT 2 medium wall loss between 25 percent and 50 percent and CAT 3 minor less than 25 percent. Figures 2 3 4 and 5 show a complete set of GUL system. The set includes ring, stem and a tough book. Figure 6 show a GUL data sheet that is used for analysis.