In order to find out if a valve is working properly with ultrasound, measurements should be taken upstream of the valve, on the valve’s body and downstream of the valve. By following the below equation, it can easily be found out if the valve is fit for duty or not. In case a series of similar valves have to be checked, it is possible to check them by comparing measurements as follows: Check that the valve is closed (supposed tight), take a measurement upstream, on the body and downstream of the valve. Create a leak by slightly opening the valve until a leakage is noted and confirmed by the readings (as per the above method). Record the readings upstream, on the body and downstream of the valve. Then, check the remaining valves in the system by comparing them with your “standard” set of readings.