Engineering task and calculation objective
The Project module is the worksheet for pressure vessel calculation: it summarizes operating and test data as well as the main components of a pressure vessel with their principal dimensions and materials in one form sheet. Before individual components such as the cylindrical shell, head, or nozzles are calculated, the user defines the common design data here – maximum allowable working pressure, test pressures for the hydrostatic test in vertical and horizontal position, external pressure, design temperature, corrosion allowance, and joint efficiency.
At the same time, the project module determines which calculation code the vessel is designed to – for example the German AD 2000 code, DIN EN 13445, or ASME – and which standard governs the material definition. The linked component modules adopt these settings, so all individual calculations consistently build on the same design data and transfer errors between form sheets are eliminated.
The result is a continuous, revision-controlled calculation cover sheet with categories, comments, revision levels, dates, and names – the foundation of the verifiable documentation that inspection organizations and notified bodies expect for conformity assessment under the Pressure Equipment Directive.
Calculation workflow
- Select the calculation code and material standard: At the start, it is defined which code the vessel is calculated to and which material standard the strength values come from. This choice controls which component modules calculate with which formulas and characteristic values.
- Enter the design data: Maximum allowable working pressure, external pressure, design temperature, corrosion allowance, and joint efficiency are entered in the form sheet – if required, separately for several chambers of the vessel. The test pressures for the hydrostatic test in vertical and horizontal position are also part of this.
- Create and link the components: The main components of the vessel (shell courses, heads, nozzles, flanges, supports) are recorded with their designations, principal dimensions, and materials and linked to the corresponding calculation modules, which automatically adopt the central design data.
- Run the individual calculations: The linked modules calculate the components according to the selected code; results such as required wall thicknesses or maximum allowable pressures flow back into the worksheet.
- Documentation and revision: Category, comments, and revision levels with dates and names complete the form sheet. Changes to the design data are documented traceably through revisions and passed on to all component calculations.
Input quantities
| Quantity | Symbol | Unit |
|---|---|---|
| Nr. | Nr. | - |
| Nr. | Nr. | - |
| Sheet of | Dokumentation | - |
| Client | Kundenbezeichnung | - |
| Description | Berechnung. | - |
| Max. allowable working pressure | 1) | bar |
| Max. allowable working pressure | 2) | bar |
| Test pressure in vertical position | 1) | bar |
| Test pressure in vertical position | 2) | bar |
| External pressure | 1) | bar |
| External pressure | 2) | bar |
| Design temperature | 1) | °C |
| Design temperature | 2) | °C |
| Corrosion allowance | 1) | mm |
| Corrosion allowance | 2) | mm |
| Joint efficiency | 1) | - |
| Joint efficiency | 2) | - |
| Comments | 1 | - |
| 2 | 2 | - |
| Design data | 1 | – |
| Design data | 2 | – |
| 5 | 5 | - |
| Comments | 6 | - |
| Sheet of | Dokum. | - |
Calculated results
| Quantity | Symbol | Unit |
|---|---|---|
| (1) | (1) | - |
| (2) | (2) | - |
| (3) | (3) | - |
| (4) | (4) | - |
| (5) | (5) | - |
| (6) | (6) | - |
| (7) | (7) | - |
| (8) | (8) | - |
| (9) | (9) | - |
| (10) | (10) | - |
| (11) | (11) | - |
| (12) | (12) | - |
| (13) | (13) | - |
| (14) | (14) | - |
| (1) | (1) | - |
| (2) | (2) | - |
| (3) | (3) | - |
| (4) | (4) | - |
| (5) | (5) | - |
| (6) | (6) | - |
| (7) | (7) | - |
| (8) | (8) | - |
| (9) | (9) | - |
| (10) | (10) | - |
Calculation options
Project calculated according to
1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10
Material data according to
1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10
Category
0 · 1 · 2 · 3 · 4
Internal or external design pressure
No · Yes
Weight of vessel and normal contents under operating or test conditions
No · Yes
Superimposed static reactions from weight of attached equipment (external loads)
No · Yes
Attachment of (1) Internals, (2) Supports
No · Yes
Cyclic and dynamic reactions due to pressure or thermal variations or mechanical loadings
No · Yes
Frequently asked questions
Why are test pressures recorded separately for the vertical and horizontal position?
During the hydrostatic test, the liquid column produces an additional hydrostatic pressure that depends on the test position: for a tall vessel tested upright, the pressure at the bottom is significantly higher than at the top, while in the horizontal position the column is smaller. For the verification of the test condition, the governing test pressure in the actual test position must therefore be applied.
What is the difference between the maximum allowable working pressure and the design pressure?
The maximum allowable working pressure is the highest pressure for which the vessel is approved in operation. The design pressure of the individual verifications must not be smaller and may include additions, for example for static heads of the medium. The safety valve setting is based on the maximum allowable working pressure; the component calculation on the design pressure.
How do the corrosion allowance and joint efficiency affect the component calculations?
The corrosion allowance c is added to the required wall thickness in all wall thickness verifications of the linked modules and is not available as load-bearing cross-section. The joint efficiency (utilization of the allowable design stress in the weld seam) reduces the strength that may be applied for longitudinally welded components; it depends on the extent of non-destructive testing. Maintaining both values centrally in the project prevents individual components from being calculated with divergent assumptions.
Can the code be changed within a project?
The calculation code is defined centrally and applies uniformly to the linked component modules – mixing codes within one verification is not permissible, because safety factors, material properties, and formulas are matched to each other. For comparison calculations, it is best to create a second project with a different code.