Air Speed Calibrations
The National Institute of Standards and Technology provides calibration services for air speed instrumentation such as Pitot tubes, hot-wire or thermal anemometers, ultrasonicanimometers, cup anemometers, 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 uncertainty of the air speed standards shown in figure 1 as function of air speed is
where VLDA is the velocity from the LDA. The air temperature, relative humidity, and atmospheric pressure in the wind tunnel during the calibration are also measured and reported.
Figure 1. NIST Airspeed Uncertainty versus airspeed. Two calibration cycles are done separated by a shutdown. In each calibration cycle, the air speed is measured five times at each air speed set point. Thus a normal airspeed calibration consists of the average of ten independent measurements at seven to thirteen air speeds.
Special tests of airspeed instruments (19030S and 19040S) can be arranged at cost. Examples include in-situ calibrations of airspeed instrumentation, proving other airspeed measurement systems, tests where appropriate scaling will allow the results to be applicable to fluids other than air, and wind speed and wind direction measurements.
Turnaround time for a single airspeed instrument is approximately 4 weeks:
However, please contact Iosif Shinder to schedule the calibration of your instrument(s).
To have your airspeed instrument(s) calibrated:
100 Bureau Drive, M/S 8361