Q. Procedure for calculating the wind force on vessels?
The National Building Code of Canada has a similar procedure for calculating the wind force on vessels as ASCE. The basic formula is F= qCgCfA.
Reference Velocity Pressure q
Obtained from Appendix C for the relevant plant location in Canada. A 1/100 value is normally used for major equipment.
Exposure Factor Ce
Obtained from Table 4.1.8.1 for the bands of heights of the vessel.
Force Coefficient Cf
Obtained from Figure B-15 for the slenderness and surface roughness of the vessel.
Gust Effect Factor Cg
For short stiff vessels (h/d<4), a value of 2 is used. For tall, flexible vessels, a calculated value is used. See NBC commentary on wind loads
Projected Area of the Vessel A
The diameter of the vertical vessel is generally increased over and above the Outside Diameter of the Insulation, by adding allowances for piping, ladders, platforms, lights and other appurtenances hanging on the side of the vessel, that increase the area exposed to the wind.