KEVOS® MAKEOS · Strength
Pressure Vessel Shell Plan (Required Thickness, Plate Chosen, MAWP, Test Water)
For a cylindrical pressure vessel with 2:1 ellipsoidal heads, what thickness is needed, what working pressure does the plate I have allow, and how much water does the hydrostatic test take?
Plan of a cylindrical pressure vessel shell and heads: the required thickness of the shell and of 2:1 ellipsoidal heads with joint efficiency and corrosion allowance and the hydrostatic test pressure (as the pressure vessel thickness tool), then the maximum allowable working pressure of the plate you choose for both, the volume and water mass for the hydrostatic test, and the mass of the shell course.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Design pressure | MPa | Internal design pressure. |
| Inside diameter | mm | Inside diameter of the shell. |
| Allowable stress at design temperature | MPa | Allowable stress of the plate at the design temperature, from your pressure vessel code. |
| Joint efficiency | Efficiency of the longitudinal weld from the code and the extent of radiography. | |
| Corrosion allowance | mm | Thickness allowed for corrosion over the vessel’s life. |
| Hydrotest factor | Hydrostatic test pressure as a multiple of design pressure, from your code. | |
| Plate and size | ||
| Plate thickness chosen (shell and heads) | mm | Nominal thickness of the plate you will use for the shell and heads (after forming thinning). |
| Shell length (tangent to tangent) | mm | Length of the cylindrical shell between the head tangent lines. |
| Plate density | kg/m³ | Density of the plate (7850 for steel). |
Method and formulas
- Shell t = P R ÷ (S E − 0.6P) + CA; 2:1 ellipsoidal head t = P D ÷ (2S E − 0.2P) + CA; test pressure = factor × P (as the pressure vessel thickness tool).
- MAWP of the shell = S E t_c ÷ (R + 0.6 t_c); of the head = 2 S E t_c ÷ (D + 0.2 t_c), with t_c = chosen − CA.
- Volume = π D² L ÷ 4 + 2 × π D³ ÷ 24; shell mass = π (D + t) t L ρ.
- Example: the shell needs 5.7845 mm; 8 mm plate allows 1.5131 MPa; the test takes 2,618 kg of water.
Limitations
- Internal pressure only; external pressure, nozzles, supports and wind need the full code design.
- Head thickness is the finished thickness after forming.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Pick a plate thickness for an air receiver or tank
- Find the working pressure of an existing shell
- Plan the water for a hydrostatic test
Who it is for
- Pressure vessel designers
- Fabrication engineers
- Inspectors
What you get
- Thickness needed for shell and heads, and test pressure
- Working pressure of the chosen plate
- Test water and shell mass
Interpreting the result
- The heads of a 2:1 ellipsoidal design need about the same thickness as the shell, so one plate thickness often serves both.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 290–294. Topic reference; no source tables or recommended settings are reproduced.
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Open the Pressure Vessel Shell Plan (Required Thickness, Plate Chosen, MAWP, Test Water) calculator
