Guided Wave Testing (GWT) is a long-range ultrasonic screening technique that can inspect tens of meters of pipeline from a single transducer ring location — useful for screening inaccessible sections like road crossings and cased pipes.

Guided Wave Testing (GWT) is a long-range ultrasonic screening technique that can inspect tens of meters of pipeline from a single transducer ring location — useful for screening inaccessible sections like road crossings, cased pipes, and elevated pipe racks. Also known as Long-Range Ultrasonic Testing (LRUT), GWT sends low-frequency guided waves along the pipe that reflect from wall loss and geometric features.

GWT advantages:
• Long inspection range (up to 50+ meters in each direction from the collar).
• 100% pipe circumference coverage.
• Can inspect through coatings and insulation.
• Rapid screening of large pipeline sections.

GWT limitations:
• Screening tool only — cannot precisely size defects without follow-up inspection.
• Sensitivity decreases with distance, coating type, and pipe features.
• Requires direct pipe access for transducer ring installation.
• Complex geometries (bends, branches) limit effective range.

For comprehensive buried pipeline assessment without excavation or direct pipe access, EMPIT’s CMI technology inspects the full pipeline length from the surface — providing corrosion detection, geometry mapping, and coating assessment that goes beyond GWT’s screening capabilities.