1) Location: At least 10 diameters of straight-length pipe work must exist upstream of the measurement point, and 5D downstream. Ideally these distances should be as large as possible.

2) Wall Thickness: For optimum accuracy, the pipe wall thickness should also be measured. Some meters are supplied with ultrasonic wall thickness gauge

3) Liquid Medium: It is essential that the type of fluid is known and also that there are no air bubbles and that the solid content does not exceed 5%.

4) Pipe Condition: The pipe wall exterior should be free from dirt, paint or corrosion. For optimum accuracy the interior wall should also be free from deposits or corrosion.