Use a reduced air velocity of 1.5 ±1 m/s (300 ±200 ft/min) to maintain test temperature conditions, and a higher air velocity of 8.9 ±1.3 m/s (1750 ±250 ft/min) typical of desert winds, to be used in the absence of specified values. Use other air velocities if representative of natural conditions. The lower air speed during temperature conditioning is to ensure that airborne dust within the chamber is minimized and the pressure applied to the dust laden test item due to wind speed is minimized during this period.
For typical testing, uniform wind speeds are provided across the test area. If the test item is large and at ground level some consideration should be given to account for the wind profile from the ground to the test item height.
Wind speed verification typically takes place prior to the testing. For this verification, the sampling rate for wind speed measurements will be a minimum of 4 samples per second. The steady state (sustained) wind speeds will be verified by averaging the wind speeds over 10 seconds with the wind generation equipment controls held constant.