1.1 This practice provides a summary of equipment and procedures for ultrasonic testing of geomembranes using the pulse echo method.

1.2 Ultrasonic wave propagation in solid materials is correlated to physical and mechanical properties and condition of the materials. In ultrasonic testing, two wave propagation characteristics are commonly determined: velocity (based on wave travel time measurements) and attenuation (based on wave amplitude measurements). Velocity of wave propagation is used to determine thickness, density, and elastic properties of materials. Attenuation of waves in solid materials is used to determine microstructural properties of the materials. In addition, frequency characteristics of waves are analyzed to investigate the properties of a test material. Travel time, amplitude, and frequency distribution measurements are used to assess the condition of materials to identify damage and defects in solid materials. Ultrasonic measurements are used to determine the nature of materials/media in contact with a test specimen as well. Measurements are conducted in the time-domain (time versus amplitude) or frequency-domain (frequency versus amplitude).

1.3 Measurements of one or more ultrasonic wave transmission characteristics are made based on the requirements of the specific testing program.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.