Bolted Flange Design

ASME BPVC Section VIII Division 1 Appendix 2

This is the documentation page for the Bolted Flange Design module. You'll find here everything you need to understand how to use our application.

1. Drawing

All the flange drawing shown in the application came from the ASME BPVC Section VIII Division 1 Appendix 2, that's why the only way to change it is through the Dimensions->Flange Type drop down list. After selecting the desired type the drawing will automatically change. The drawing with the real dimensions will only be shown in the results page but we are trying to implement it in the input page. If you want to follow all the upcoming changes see the Development Page

In the future we'll also show the drawing of the gasket[1], bolt and top view of the flange as it may help the user to better understand what is being designed.

2. Fields

Below is a list of all the available fields in the Module.

2.1. Project Information

  • Description: brief description of what you are designing. For example: heat exchanger cover or flange for inlet nozzle. It'll help you identify which part of the pressure vessel this calculation belong.
  • Use Registered Project: if checked, the application will load all the projects registered by the user and will automatically fill the Customer and Report Number fields. Please, see the Project Management documentation for more information.
  • Choose a Project to add this Module: this field will appear only if the user checked the Use Registered Project checkbox.
  • Project Name: every project have a name and such a name will be important to identify it. Can't be blank.
  • Customer: the name of the company or the person that you are designing the flange for. It can be left blank.
  • Report Number: all engineering documentation must have an unique code (can be alphanumeric) to identify it so it can easily be tracked if necessary.
  • Auto-Generate Module ID: if checked, the application will automatically create an unique ID for the module.
  • Module ID: the user must create (or let the application generate it, as explained above) an unique ID for every calculation generated so it can be tracked.
  • System of Units: the application current support two types of units: International System of Units (also known as SI) and Imperial System of Units. The type of units can be changed any time as all the values from the fields are updated according to the system choosen.
    Description International System of Units Imperial System of Units
    Pressure MPa psig
    Area mm^2 in^2
    Length mm in
    Density kg/m^3 lbf/in^3
    Force N lbf

2.2. Process Information

  • Fluid: although this field can be left blank, we highly advise the user to fill it, because it's a common pratice to use a project as reference to another one and the fluid is an important variable while designing a pressure vessel, specially regarding the material specification.
  • Internal Design Temperature: design temperate as specified in the UG-20.
  • Internal Design Pressure: design pressure as specified in the UG-21.

2.3. Dimensions

  • Flange Type: flange figure according to Appendix 2, 2-4. For now the application don't support blind and reverse flanges.
  • Flange Construction: integral, loose or optional. See Appendix 2, 2-4 for more detail.
  • Corrosion Allowance: margin that can be used in the calculation if the user chooses so.
  • Use Corrosion Allowance in the Calculation: if the user tick this box, the value from the corrosion allowance field will be used in the calculation. Otherwise it'll only appear in the input part of the calculation report.
  • Joint Efficiency of the Pipe: factor used to calculate tn (nominal thickness of shell or nozzle wall to which flange or lap is attached).
  • Use "B1" instead of "B" if B < 20 * g1: when B (flange inside diameter) is less than 20 * g1, it will be optional for the designer to substitute B1 for B in the formula for longitudinal stress SH.

Note: some fields that are self-explanatory won't be shown in the list below (for example: flange outside diameter and flange thickness).

2.4. Bolting

  • Bolt Unit Type: it can be Imperial (ASME B1.1) or Metric (BS 3643).
  • Bolt Size: it'll show the bolt size according to the select bolt type.
  • Bolt Root Area: section area of the bolt calculated using its root diameter.
  • Number of Bolts: number of bolts defined by the user, by obvious reason it can't be decimal and it's a good pratice to use even number and if possible, multiple of four.

Note: some fields that are self-explanatory won't be shown in the list below (for example: bolt circle diameter).

2.5. Material Properties

  • Material Name: for now only ASME material can be used in the Bolted Flange module, so this field show all ASME material included in our database and which can be used to fabricate the flange (it exclude, for example, fasteners materials). Have a look in our Material Database page.
  • Material Listing: this field is used when a material have more than one properties value but keep the same name and UNS number. It's the case when a material have the G5 note, which change the allowable stress values. The user should check the Material Database page the right listing number and material properties before using it.
  • Yield Strength at Design Temperature: this field is automatically filled with the information from ASME BPVC Section II, but the user can change it if needed to.
  • Allowable Stress at Design Temperature: value taken from ASME BPVC Section II for the design temperature (see tab Process Information). Basicaly it's the tensile strength or yield strength with safety factor. Please, see ASME BVPC Section II Part D Appendix 1 for more detail.
  • Allowable Stress at Ambient Temperature: the same as the field above but using the room temperature (we consider 25°C) instead of design temperature.
  • Material Density: this field is used to calculate the flange weight.
  • P-Number Thickness: P-Numbers are assigned to base metals for the purpose of reducing the number of welding and brazing procedure qualifications required.
  • External Pressure Chart: taken from Section II, it were established in order to facilitate a conservative approach in determining external pressure ratings for components covering a wide range of geometries, materials, and conditions.
  • UCS-66 Curve: curve used to establish impact testing exemptions for steels listed in Part UCS from Section VIII. When such a curve is used, impact testing is required for a combination of minimum design metal temperature (see UG-20) and thickness, which is below the curve assigned to the subject material. See UCS-66.
  • Elastic Modulus at Operating Condition: value taken from Section II using the design temperature and material as input.
  • Elastic Modulus at Seating Condition: same as above but using room temperature as input.
  • Is the Material Normalized: tick the box if the material is normalized. It'll automatically update the UCS-66 Curve.

Note #1: the content of the Material Properties section is divided between Flange and Bolt material but the field name and its description is same for both.

Note #2: some fields from this section can be edited by the user (for example, the allowable stresses and elastic modulus) and a message saying that the user have changed the value from application will appear in the results page.

2.6. Gasket

  • Use Gasket Database: we have a database with standard values for gasket factor and unit seating load for different type of gaskets. If the user check the box, a drop down list called Gasket Type will appear and the user can choose the closest to the one he'll actually use.
  • Gasket Factor:
  • Gasket or Joint-Surface Unit Seating Load:
  • Flange Facing Sketch:
  • Column from Table 2-5.2:
  • Flange Face Width:
  • Serration Depth:
  • Nubbin Width:

Note: some fields that are self-explanatory won't be shown in the list below (for example: gasket thickness).

2.7. Settings

  • Show Factors Calculation: if the user choose yes then, the result page will show the step-by-step calculation of the factors (K, Y, U, T, Z, h0, A, C to C37, E1 to E6, V, VL, subf, d, F, FL, sube and L); if the user choose Only Results then, a table with the results value will be shown; last if the user choose No then, no calculation or calculated values will be shown.
  • Show Results with Toggle/Accordion Effect: if the user choose yes then, the results will be shown with toggle or accordion effect separated by section, just like in the input page, where the user must click in the desired section to show its content.
  • Show Flange Image in the DOCX file: if the user choose yes then, the flange image with actual dimensions (inserted by the user) will be in the DOCX file, if the user choose no then the DOCX file will have no image.

Note: this settings will affect the results page and the DOCX gerated by it.

3. Projects

Every Module must be stored inside a Project which must have an unique Report Number. A Customer may have as much project as needed and a Project can have as much Modules as needed too.

For example: imagine a customer named XYZ and we need to design two equipment for them Pressure Vessel ABC and Pressure Vessel DEF (these can be the Project Name), with report number SKABC and SKDEF respectively. These two vessels will have each an head, shell, flange and saddle support.

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1 Manageable DocX, 2013, boots