BASIC WIND SPEED is the fastest-mile wind speed associated with an annual probability of 0.02 measured at a point 33 feet (10 000 mm) above the ground for an area having exposure category C.
From SBC 301, under SECTION 6.2 – DEFINITIONS
Basic Wind Speed, V. 3-second gust speed at 10 m above the ground in Exposure C (see Section 6.4.2) as determined in accordance with Section 6.4.1.
BASIC 3-SECOND GUST WIND SPEED IN km/h FOR SELECTED CITIES OF SAUDI ARABIA.
ADOPTED FROM SAUDI ARAMCO DATA SAES A-112.
When required, the 3-second gust basic wind speeds of Figure 1609 shall be converted to fastest-mile wind speeds, Vfm, using Table 1609.3.1 or Equation 16-34.
where: V3S = 3-second gust basic wind speed from Figure 1609.
TABLE 1609.3.1 EQUIVALENT BASIC WIND SPEEDS a, b, c
For SI: 1 mile per hour = 0.44 m/s.
a. Linear interpolation is permitted.
b. V 3S is the 3-second gust wind speed (mph).
c. Vfm is the fastest mile wind speed (mph).