Per definition by ASCE 7-16 & ASCE 7-10, Section 26.2 is defined as:
BASIC WIND SPEED (V): Three-second gust speed at 33ft above the ground in Exposure C (see Exposure Categories) as determined in accordance with ASCE 7-16 (10) Section 26.5.1.
The wind shall be assumed to come from any horizontal direction. The basic wind speed shall be increased where records or experience indicate that the wind speeds are higher than those reflected [in ASCE 7-16 Section 26.5.1].
Basic wind speed is typically reported in ultimate load (Vult). This is a factored value that is reduced by the formula Vasd=Vult* sqrt(0.6). Vasd is the allowable design wind speed.
Also important to note that there are different values for sustained vs 3 second gust winds as well as one minute fastest mile. When you hear a weather report stating ‘gusts up to XXmph’, that’s typically the 3 second value vs the sustained winds reported.
Important to note that wind speed is not wind pressure. There are many wind pressures that could develop from a single wind speed. Click here to learn more.
Here’s a helpful video found to explain the difference between basic wind speed & wind gust.
Last Update: April 8, 2021