While not necessary or even particularly relevant for the direct purpose of flow measurement,
this inference of the fluid’s speed of sound is nevertheless useful as a diagnostic tool. If the true
speed of sound for the fluid is known either by direct laboratory measurement of a sample or by
chemical analysis of a sample, this speed may be compared against the flowmeter’s reported speed
of sound to check the flowmeter’s absolute transit time measurement accuracy. Certain problems
within the sensors or within the sensor electronics may be detected in this way.