Tech File: Next-gen Acoustic Flooded Member Detection

Impact Subsea released a new generation of underwater, Flooded Member Detection system: ISFMD V3, designed to provide an intuitive yet simple-to-use flooded member detection system for deployment by divers or remotely operated vehicles.

The system provides capability to test and store results for multiple members  at a time. Multiple members can be preconfigured prior to commencing the survey with details of diameter, length and angle. Multiple readings can be logged per member, including at different test positions around the member. 

Members are automatically classified as flooded, part flooded or dry, using an advanced digital correlation detection technique.  This technique allows acoustic returns to be detected even if the return is below the ambient noise level.  This approach to detecting an acoustic return ensures exceptionally high accuracy and reliability in readings.

The ISFMD V3 system operates by transmitting an acoustic pulse into an underwater member.  If there is a liquid inside the member the pulse will
transfer through the member, bouncing off the opposite member wall and back to the probe. If however the member is full of air the signal is attenuated and will not bounce back to the probe.

Snapshot of the ISFMD V3 user interface showing a member which has had a number of measurements conducted on it. Image courtesy Impact Subsea