API 620-Cylinder Shell Thickness

Dear All,

I have started using API 620 for following tank.

Tank internal design pressure / pressure rating (As per API 620) = 0.8 bar (g)

Tank Diameter = 3450 mm Tank height = 5900 mm liquid density = 920 Kg/m3

tank shell thickness = 04 mm (proposed), Top cone roof thk = 04 mm (proposed)

Now I calculated the 2 forces at a section in shell at the bottom of shell

They are T1 and T2 as per API 620 nomenclature. T1 = 10570 N/mm and T2 = 229 N/mm

When I am using T1 as the largest for shell thickness calculation using Sst = 126 N/mm2 (linear interpolation) and E=.85 the thickness comes too much higher 98mm???

Please help.

Regards

ASD23789