ON SITE REQUIREMENTS
- Access to the pipe and removal of about 3.3 ft length of insulation at each test point
- Surface preparation is usually limited to scraping off loose paint and scale
- At least 3 inch of clearance between pipes to fit the tool
- Pipe surface temperature must generally be below 160 °F although high temperature 644 °F rings are available
GWT FUNDAMENTALS
Ultrasonic signals are swept over a full frequency range, in both directions from the GWT tool, in a single shot. In addition to faster, more efficient data acquisition, having all the data in a single file makes analysis faster and more certain. Sophisticated processing and analysis software allows trained operators to interpret these signals and report their findings. Special, wide frequency probes are available for cases such as buried pipe where attenuation is too high over the standard frequency range.
Enhanced Focusing Capability (EFC) rings (pipe 4 inch and above) improve defect characterization and provides color coded C-scan type maps of the pipe. In effect, the EFC processing focuses on all reflectors over the entire range of the shot. This improves sensitivity as well as making the guided wave data more understandable to the end user.