VDI/VDE 2650 Part 4 lists the most important application-specific faults and fault conditions for flow measurement devices and their occurrence from the users' point of view. The occurrences indicated for each measurement method are meant as relative weightings. Occurrence 1 means often, Occurrence 3 means rare. In this context application-specific faults may not be understood as device failures. Fault conditions indicate deviations from the intended operating modes.