Bolt Sets

In the Project Environment dialog, in [library or project] > Components > Bolt Sets you can manage Dimension Tables that describe bolt sets for flanged connections. A bolt set defines a range of bolt sizes, using the following properties: the nominal size of the connection, bolt length, bolt diameter, and the number of bolts, nuts, and washers in the set.

Defining bolt sets

Define the required bolt sets.

Prerequisites

  • There is a Catalog Part for the bolt, the nut, and the washer, and you have the Object IDs for these parts. You need the IDs when defining the bolt set.

Do the following:

  1. In the Project Environment dialog, browse to [project or library] > Components > Bolt Sets.

  2. Select New > Bolt Set. The Dimension Table Edit dialog opens.

  3. Enter a name for the bolt set.

  4. You can skip the following settings:

    • Geometry Type – This is automatically set to DM_GT_AUXCOMP (3).

    • Geometric Shape – This is automatically set to "No Shape".

    • Isometric Drawing – This is automatically set to "no iso symbol".

  5. In the Dimensions section, define the dimension attributes of the bolts:

    1. Click Attributes. The Edit Dimension Attributes dialog opens, showing the following attributes:

      • NS (NS) – Nominal size of the pipes in the flanged connection.

      • bd (Diam) – Diameter of the bolt, nut, and washer.

      • bl (Length) – Length of the bolt.

      • bolt (Pieces) – Number of bolts.

      • nut (Pieces) – Number of nuts per bolt.

    2. Add the following attribute, if needed:

      • wash (Pieces) – Number of washers per bolt.

    3. For bolt, nut, and washer, set Alt Dim Enable to yes, copy the relevant Object ID from the Catalog Part to the Alt Dim Name field, and insert a plus sign (+) before the ID value.

    Then click OK.

  6. In the Dimensions section, define the range of bolt sizes in the bolt set.

    1. Click Values. The Dimension Table Edit Tool dialog opens.

    2. Click Open Line, and enter the required dimension values. Leave the alternative dimension fields of bolts, nuts, and washers empty.

    3. Click Open Line to add another size in the same way.

    4. When all the sizes are defined, click OK.

  7. Click OK.

Next, you can assign the bolt set to the required piping specifications, as described in Assigning bolt sets and gaskets to flange joints.

Using automatic bolt length calculation

The default bolt length of a flanged connection is a fixed value that is based on the nominal size of the connection. However, project administrator can enable automatic bolt length calculation, which enables bolt length to be dynamically calculated based on factors such as flange thickness, gasket thickness, and the number and thickness of nuts and washers.

Configuring the bolt set | Configuring the joint materials | Configuring GDLs | How bolt length is calculated | How bolt length is selected

Configuring the bolt set

To enable automatic bolt length calculation, set the "Bolt length method" attribute in the bolt set to "Automatic". As a result, Plant Modeller ignores the bolt length value defined in the bolt set and chooses a bolt of suitable length instead.

The threaded extension of the bolt can be defined using the "thread_extension" length dimension in the bolt set. If this dimension is not defined, then bolt length calculation automatically uses 1/3 of bolt diameter for the threaded extension.

Note: If the flanged connection uses stud bolts, the automatic calculation multiplies the threaded extension by two.

Configuring the joint materials

In automatic bolt length calculation, all the joint materials (bolt, washer, nut) must have the "Joint material" attribute set to the appropriate value:

  • "Bolt" or "Stud bolt"

  • "Nut"

  • "Washer"

Also, the bolt, the washer, and the nut must have a Length dimension defined in their Dimension Table. If the nut has no length defined, automatic bolt length calculation uses bolt diameter to define nut length.

Configuring GDLs

If the flange uses GDL, automatic bolt length calculation requires that the connection node in the GDL has either "Flange thickness" or "Bolt length for tapped holes" defined. In addition, you can define a minimum bolt length for tapped holes.

For more information on these settings, see Node.

How bolt length is calculated

Flange thickness:

  • For shape-based flanges, flange thickness is taken from the respective value in the Dimension Table.

  • For GDL-based flanges, flange thickness is taken from the "Flange thickness" value of the connection node.

Gasket thickness:

  • The thickness of the gasket between the flange and the connected object.

Threaded extension:

  • If the bolt set has the "thread_extension" length dimension, then its value is used.

  • If the bolt set does not have "thread_extension", then 1/3 of bolt diameter is used.

Tapped hole minimum length:

  • If GDL node has "Minimum length for tapped holes" set to zero, then 1.5 * bolt diameter is used.

  • If GDL node has "Minimum length for tapped holes" set to greater than zero, then its value is used.

The calculations that are performed to determine the required length of a bolt or stud bolt when a flange is connected to another flange or when there is a piece of equipment between the flanges are described below.

Flange – flange

Machine bolt

Minimum bolt length when bolt passes through both flanges:

flange thickness + gasket thickness + other flange thickness + thickness of all washers + thickness of all nuts + threaded extension

Minimum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + tapped hole minimum length + thickness of all washers + thickness of all nuts

Maximum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + other flange "Bolt length for tapped holes" + thickness of all washers + thickness of all nuts

Stud bolt

Minimum bolt length when bolt passes through both flanges:

flange thickness + gasket thickness + other flange thickness + thickness of all washers + thickness of all nuts + 2 * threaded extension

Minimum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + tapped hole minimum length + thickness of all washers + thickness of all nuts +threaded extension

Maximum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + other flange "Bolt length for tapped holes" + thickness of all washers + thickness of all nuts + threaded extension

Flange – wafer valve – flange

Machine bolt

Minimum bolt length when bolt passes through both flanges:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + other flange thickness + thickness of all washers + thickness of all nuts + threaded extension

Minimum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + tapped hole minimum length + thickness of all washers + thickness of all nuts

Maximum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + other flange "Bolt length for tapped holes" + thickness of all washers + thickness of all nuts

Stud bolt

Minimum bolt length when bolt passes through both flanges:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + other flange thickness + thickness of all washers + thickness of all nuts + 2 * threaded extension

Minimum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + tapped hole minimum length + thickness of all washers + thickness of all nuts + threaded extension

Maximum bolt length when bolt only passes through one flange:

flange thickness + gasket thickness + wafer valve length + other gasket thickness + other flange "Bolt length for tapped holes" + thickness of all washers + thickness of all nuts + threaded extension

Flange – wafer valve with tapped holes – flange

Valves that have a wafer-style body but also a lug with tapped holes require two bolt sets whose lengths are calculated as follows:

  • The bolt length for the wafer-style connection is calculated in the same as way as in Flange – wafer valve – flange.

  • The bolt length for the lug-style connection is calculated in the same way as in Flange – flange with tapped holes. The values for "Bolt length for tapped holes" and "Minimum bolt length for tapped holes" are taken from the valve node.

How bolt length is selected

After performing automatic bolt length calculation, the program selects the bolt as follows:

  • If the bolt passes through both flanges, the program selects a bolt whose length is equal to or greater than the calculated minimum length. There is no upper limit for bolt length in this connection type.

  • If the bolt only passes through one of the flanges, the program selects a bolt whose length is equal to or greater than the calculated minimum length AND equal to or less than the calculated maximum length.

    If there are multiple candidates, the program selects the bolt whose length is nearer to the maximum length.

Related Topics

Bolt information

Bolt, nuts and washers

Gaskets