4.1.4. Calculation Formula

For a standard bolt set, the bolt length is calculated as follows:

Bolt length = Sum of connected flange thicknesses
            + (Nut thickness × Number of nuts)
            + (Washer thickness × Number of washers)
            + (Additional length × Number of additional parts)
            + THREAD DEPTH
            + Valve flange thickness × Number of valves (when connected to a valve)
            + Nozzle offset × Number of nozzles (if connected to a nozzle)
            + Gasket thickness × Number of gaskets (if gaskets are present)
            + Stub end offset × Number of stub ends (if present)

Example of the effect of gasket thickness: In a flange connection with a 2 mm thick gasket compared to an otherwise identical connection with a 10 mm thick gasket, there is a difference of 8 mm in the calculated bolt length. Different gasket thicknesses in the model are thus directly reflected in the calculation results.

Loose flange connections with stub end: For loose flange pairs, the flange offset of the connected stub end is additionally included in the calculation. For a stub end with e.g. 10 mm flange offset, the calculated bolt lengths will be correspondingly longer than for a comparable weld neck flange connection. The prerequisite is that the multiplier STUBEND is set in the configuration file and the flange offset is maintained on the stub end component.

The result is then rounded to the next standard length from the RoundLength table:

UP: Rounds up to the next length that is equal to or greater than the calculated value.
DOWN: Rounds down to the previous length that is equal to or less than the calculated value.

When using "Update Exactly", no rounding occurs.

If the calculated length exceeds the maximum available standard length, the bolt is marked as "Fail" in the report.