Comparison of Guided Wave Testing Systems

    The guided wave system using MsS probes have more merits compared to the use of discrete piezoelectric transducer belts. The following list is provided to aid potential purchasers of guided wave systems by detailing out those specifications necessary to perform accurate guided wave testing. The data in brackets are specifications of the MsS system and applicable GWA information.

1. Operating frequency [5 kHz to 250 kHz]
2. Price of the system is reasonable compared to other guided wave systems.
3. Additional maintenance cost is very low compared to other guided wave systems.
4. Defect detection sensitivity [Sensitivity is very high with sector probe and high-frequency operation]
5. Sum of dead zone length and near field length [5 inches with 128 kHz]
6. Inspection range [about 500 ft along one direction for aboveground painted pipeline for finding 2 or 3 percent cross-sectional area defect]
7. Weight of equipment [about 4.5 kg]
8. Weight of probe [0.8 kg for 24-inch pipe probe; crane support is not needed to lift the guided wave probe]
9. Signal-to-noise ratio [Less flexural mode generation than any other guided wave systems]
10. Broad band operation [MsS can test 5 to 250 kHz with one strip installation]
11. Spatial resolution or number of cycles [MsS uses 1 or 2 cycles for GWT]
12. Finding defect around the pipe circumference [use of sector probe]
13. Inspection locations per day [Inspection of 5 to 30 locations per day depending on pipe size and accessibility]
14. Signal repeatability [MsS system generates highly-repeatable data for guided wave monitoring with 360-degree continuous probe]
15. High temperature application [MsS probe can inspect up to 300 Celsius degree once it is bonded with epoxy]
16. Size of probe [MsS probe is very thin and thus can be installed on the pipe having about 0.4-inch gap between pipes.]
17. Training [The MsS technique is trained by a Level III in GWT who is also ASNT NDT Level III in UT and ET and has more than 11 years of experience in GWT and holds 13 US patents in guided wave application]