Uncertainties and their estimated maximum errors in field measurements using Pitot tube for air flowrate calculations
Introductory Air balancing, trouble-shooting, and system evaluation in dust collection and industrial ventilation systems all require accurate measurements of air flowrates. Normally, the Pitot tube and magnehelic gauge (or manometer) are used to measure the velocity pressure and static pressure inside of a duct (round or rectangular), and then the air flowrates are calculated based on the measured values. This article talks about 5 kinds of uncertainties that always happen in field measurements using Pitot tube, the estimated maximum errors with some of them, and how to avoid some uncertainties with recommendations from manuals and standards ( ISO 3966 and NF X 10-113). Uncertainties, maximum errors, and how to avoid some of them In addition to the inherent errors from Pitot tube and gauges themselves (calibration, resolution, drift, etc., sometimes with the correction factor of Pitot tube involved), there are other errors we have to...