Wind Load – ANSI A58.1 - 1982

CAEPIPE calculates Design Wind Force F as follows to calculate wind load acting on each pipe element.
F = q x Shape factor x Af (lbs)
where,
Af is the area of the piping plus insulation projected on a plane normal to the wind direction
q = Dynamic pressure due to wind (lbs/ft2) = 0. 0.00256V2 x I2 x (Kz Gz Cf)
V = Basic Wind Speed, V (mph), from Basic Wind Speed Map, for your region.
Shape factor = 0.6 for Circular cross-section (to be input into CAEPIPE for Wind)
“Section 6” of ANSI A58.1 - 1982, Minimum Design Loads for Buildings and Other Structures can be referred to arrive at the values for [I2 x (Kz Gz Cf)].
Importance Factor, I2, is determined according to structure category and location:
Value of I2 for:
Other Areas
Within 100 mi of Ocean line
Chemical plants, refineries, industrial facilities, and power plants not required in an emergency
1.00
1.11
Power Plants required in an emergency
1.15
1.24
Determine combined Velocity Coefficient, Gust Factor, and Force Coefficient, Kz Gz Cf) according to height of piping;
Height of Piping
KzGzCf
At or below 50’ above ground
1.23
Above 50’ at or below 100’ above ground
1.44
Above 100’, at or below 200’ above ground
1.68
Note:
If Wind Speed as a function of Elevation is input, the factor SQRT[(I2 x (Kz Gz Cf))] has to be multiplied with the Actual Wind Velocity as a function of elevation to arrive at the Wind Speed that is to be input at each elevation manually.
For example, if the Actual Wind Speed is 60 mph at an elevation of 50’, I2 as 1.00 and Kz.Gz.Cf as 1.23, SQRT[1.00 x 1.23] = 1.109. So, V = 60 x 1.109 for up to 50’ elevation = 66.54 mph. This should be input in the CAEPIPE Wind dialog.
If Pressure as a function of Elevation is input in CAEPIPE, the factor [I2 x (Kz Gz Cf)] and the Shape Factor have to be incorporated in the Pressure input at each elevation manually. This is because CAEPIPE currently uses the Shape Factor input into Wind dialog only for Velocity vs Elevation option and not for Pressure vs Elevation option.