Minimum Technical Requirements for Reliable Guided Wave Testing of Pipelines

Guided wave testing (GWT) is a widely used long-range ultrasonic method for pipelines and other elongated structures. Despite its maturity, significant inconsistencies exist among systems and reports in how calibration is performed, how amplitude is expressed, how many frequencies are used, and how findings are documented. These inconsistencies affect reliability and prevent meaningful comparison between inspections or organizations. This paper proposes minimum technical requirements for reliable guided wave testing, organized into six areas: instrumentation capability, the three essential calibrations, amplitude reporting, multi-frequency operation, signal verification, and reporting documentation. Each requirement is grounded in guided wave propagation physics and is consistent with conventional ultrasonic testing practice. The requirements address deficiencies identified in current practice, including uncalibrated amplitude scales, misapplication of energy-ratio terminology to amplitude measurements, single-frequency inspection, and the absence of detailed signal verification. A compliance checklist is provided.