Engineering task and calculation objective
This module selects welding-neck flanges to DIN 28034 — the German flange standard for process equipment, which specifies welding-neck flanges for agitated vessels and other process apparatus. Starting from nominal size, operating pressure, and operating temperature, the program determines the appropriate flange, checks the allowable operating temperature and the allowable operating pressure against the tables of the standard, and additionally outputs the flange weight for weight and transport considerations.
Welding-neck flanges to DIN 28034 are typically used on vessel nozzles, manholes, and equipment connections where defined sealing face types such as tongue and groove or male and female are required. The standard assigns a pressure-temperature rating to each combination of nominal size and pressure rating, so the designer can check whether the flange is suitable for the operating conditions without performing a separate strength calculation.
Anyone who wants to calculate or select a vessel flange to DIN 28034 saves the manual page-turning through the standard with this table module: enter the operating data, compare against the allowable limits, and transfer dimensions and weight — for example directly into the nozzle schedule or the equipment weight summary.
Standard and calculation basis: DIN 28034: 2005-06
Calculation workflow
- Enter the operating conditions: The operating pressure and operating temperature of the connection are entered along with the desired nominal size. The selection temperature determines which row of the pressure-temperature rating governs.
- Select the flange from the standard: The module assigns the welding-neck flange to DIN 28034 to the nominal size and reads out the associated table values, including the sealing face type (e.g. tongue/groove or male/female).
- Check the allowable limits: The entered operating pressure is compared with the allowable operating pressure at the selection temperature, and the operating temperature with the allowable operating temperature per DIN. Only if both conditions are met is the flange suitable for the application.
- Transfer the results: The results are the flange dimensions and the flange weight, available for parts lists, equipment weight determination, and the design of the bolted joint.
Input quantities
| Quantity | Symbol | Unit |
|---|---|---|
| Nominal width Flange selection temperature | D TA | mm |
| acc. DIN Allowable operating temperature | DN T | °C |
| Allowable operating pressure | p | bar |
| Pipe connection size | B1 | mm |
| Outside diameter Blade thickness | D C1 | mm |
| Bolt circle diameter Length | K H2 | mm |
| Outside diameter Blade thickness | D C1 | mm |
| Bolt circle diameter Length | K H2 | mm |
| Flange hub length Hub end thickness | H3 S | mm |
| Radius Hub base tapering | r f | mm |
| Flange hub length Hub end thickness | H3 S | mm |
| Radius Hub base tapering | r f | mm |
| Outside diameter Outside diameter | x y | mm |
| Inside diameter Inside diameter | w z | mm |
| Outside diameter Outside diameter | x y | mm |
| Inside diameter Inside diameter | w z | mm |
| Bolt hole diameter Number | L (M ) n - | mm |
| Bolt hole diameter Number | L (M ) n - | – |
| Bolt hole diameter Number | L (M ) n - | – |
| Flange weight | m | kg |
| Operating temperature | TB | °C |
| Operating pressure | pB | bar |
| acc. DIN Allowable operating temperature | DN T | mm |
| Nominal width Flange selection temperature | D TA | °C |
Frequently asked questions
How does DIN 28034 differ from DIN EN 1092-1?
DIN EN 1092-1 is the general piping flange standard, whereas DIN 28034 is tailored specifically to process equipment and specifies welding-neck flanges with the sealing face types and pressure-temperature ratings common in that field. Connection dimensions are largely compatible, but in equipment engineering the selection is sensibly made according to the equipment standard.
What does the allowable operating temperature in the table mean?
The pressure-temperature rating of the standard specifies up to which gauge pressure a flange of a particular material group may be used at a particular temperature. As the temperature rises, the allowable operating pressure decreases, because the strength values of the material decrease. Intermediate values may generally be interpolated linearly.
Does table-based selection replace the tightness verification of the flanged joint?
For standard cases within the rating tables, yes. With high additional loads from piping, special gaskets, or tightness requirements (e.g. the German TA Luft clean-air regulation), the complete joint should additionally be verified to DIN EN 1591-1, since the table rating accounts for neither external moments nor the real gasket behavior.