The CHUM (Cross Hole Ultrasonic Monitor) uses the Cross-hole Sonic Logging (CSL) method to perform high-resolution quality control of deep foundations.
The system uses an ultrasonic wave sent from a transmitter to a receiver pulled through water filled access tubes embedded in the concrete. The measured arrival time and energy are strongly dependent on the concrete quality.
Additional methods supported by the CHUM are Single hole Ultrasonic Testing and Tomography(2D & 3D)
The CHUM is fully compliant to ASTM D6760-08