Dear Members,

I have vertical vessel with 24.1 bars design pressure, 260 degree celcius , ID = 440mm with 9.53mm thickness and 660mm TL/TL with 550mm half skirt locate at upper/main deck (12.2m to 16.8m). My clients(Shell & Technip)has comment that wind,dynamic and transportation loads and motion effect shall be accordance with their spec.(DEP 37.81.10.31 /API 2A-WSD 21st ED). From spec. given, wind pressure value shall be calculate based on API RP-2A section 2.3.2c with formula for wind drag force is F = (ρ/2)μ^2 CsA;which is F = wind force, ρ = mass density of air(0.0023668 slugs/ft^3 for standard temperature and pressure), μ = wind speed(ft/s, Cs = shape coefficient, A = area of object(ft^2).

As per API RP-2A section 2.3.2e Cs for Cylindrical sections = 0.5,and overall projected area of platform = 1.0.

Also table wind speed and dynamic load as per attachment to follow.The problem is how to apply this spec into wind design code at PV elite and to find wind pressure.

I think, at pv elite i want select user define, but i lack of knowledge to convert information as above to wind pressure.

appreciate if anyone could guide or advice me to solve this problem.

Hello Faizol

PV Elite does not cater for the specification or codes that you mention. The density of air which is stated as 0.0023668 slugs/ft^3 converts to 1,22 kg/m^3 which is reasonable. Most wind codes use a variation of this value. The only way of simulating this is to set the Wind Code to 'User Defined' and enter the wind pressure for each height. This is fairly easy to compute Pw = Cs * (ρ/2)*μ². That is one way of doing it. Perhaps that would satisfy you clients.

Dear Ray,

Sir, thank for your valuable reply.

Thank.