Vessel subjected to full vaccum

[unbound]

I am checking the shell thickness of a 2232mm dia pressure vessel x 4077mm long. The design ambient is 40 C and material is boiler plate. Design pressure is atmospheric to full vacuum. Vessel is not stiffened.

Using ASME code, factor A by formula is 0.0017, factor B is 25992.4, I get an allowable pressure of 17.1 bar. Or to put another way, allowing for 2 bar external pressure for full vacuum, I only require 5.5mm thickness.

Vessel will be made 16mm thick and I would not change without full calcs done. But I would like to have an idea if the material thickness could be reduced.

Using the PDQ$ formulas I get 12.65 bar at 16mm or at 2 bar external pressure - 7.8mm.

Can anybody confirm these values.

 

[JohnGP]

Unbound,

Without knowing the material spec of your "boiler plate", my quick and dirty spreadsheet (based on ASME VIII) tells me that you would need at least 9.5mm shell thickness if you didn't have stiffeners. That's using SA516-70 though, and 2:1 SE heads (and no corrosion allowance). I used 1 Barg as the external pressure as well.

Regards,
John