The CHUM (Cross Hole Ultra sonic Monitor) uses the Crosshole Sonic Logging (CSL) method to perform high-resolution quality control of deep foundations.

The system uses an ultra sonic 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. [ overview of this test method ]

Additional methods supported by the CHUM are Single Hole Ultra sonic Testing (SSL/SHUT) and Tomography (two- and three-dimensional).

The CHUM is fully compliant to ASTM D6760 - 16, AFNOR NF P 94-160-1 and additional standards