Air Speed Calibrations
The National Institute of Standards and Technology provides calibration services for air speed instrumentation such as Pitot tubes, hot-wire, thermal, ultrasonic, cup, or propeller anemometers, and the like.
The calibration service is performed in the dual test-section wind tunnel over a range of 0.25 m/s to 45 m/s (0.57 miles per hour to 90 miles per hour) with a test section of 1.5 m by 2.1 m (5 ft by 7 ft). The standard for air speed measurement at NIST is a fiber optic Laser Doppler Anemometer (LDA), which is calibrated with known velocities produced by a rotating disk. The air speed calibrations are done by direct comparison of the response of the instrument under test with the response of a NIST LDA. The calibration uncertainty is given by the formula
U(v) = 0.42 + 0.0039 e(1.22/v) (k = 2)
where v is the air speed (in m/s) and U is the relative uncertainty (in % of v). The air temperature, relative humidity, and atmospheric pressure in the wind tunnel during the calibration are also measured and reported.
Two calibration cycles are performed separated by a shutdown. For every calibration cycle, the air speed is measured five times at each air speed set point. Thus a normal air speed calibration consists of the average of ten independent measurements at seven to thirteen air speeds.
Calibration fees for this and other services can be found in the Fee Schedule available online from the NIST Calibrations Website. To read more about our facilities, see the NIST Special Publication 250-79.
To have your airspeed instrument(s) calibrated: