Flange Equipment Design and Calculations

Once you have created or imported your Flange FLOCs, you can assign design parameters for each of the Flanges. This can be completed from the Flange Design section of the Flange’s Details page.

To define a Flange’s design:

• Go to the Flange Equipment Details page.

• Scroll to the Flange Design section.

• Click Edit.

• Use the top right buttons to highlight the applicable fields on the Design tab.

Color coding scheme:

The Design section is color codes as follows: All the calculated values, as well as the values from the lookup tables (based on entered parameters), are colored in green. If you alter a value, or select a value different from the suggested value, the field will be colored in red to indicate a discrepancy with the standards. Recommended fields are colored in blue, and optional fields remain white.

Recommended

On the Design tab – specify the Tightening data and Recommended Specs:

• Click the Recommended button (top right) to highlight the applicable fields (see above figure).

• Tightening Step 1– Used for Torque or Tensioning calculations:

  • Flange Standard - Select the Flange construction code or specify if not listed. The selected Standard will determine which specific Flanges are (or are not) available to select. If the selected Standard is “ASME B16.47A”, then you will only be able to select Flange Sizes between NPS 26 and NPS 60.

  • Flange Size - this is inherited from the level 4 Equipment (if it has Pipe Size). Note: The steps in flange size are in accordance with the ASME B16.5 standard.

  • Class Rating (dropdown).

When Flange Size and Class Rating is inputted:

• Tightening Step 2 fields are auto filled with default values.

• IMS calculates the minimum Torque / Tension value. See Appendix A: Flange Calculations.

  • Click the arrow < to apply the calculated Torque / Tension value, or

  • Input another value. Note: A warnings is given if this is below the calculated value.

• Tightening Step 2 - auto filled with default values, based on Flange Size and Class Rating entered in Step 1:

  • Stud Size (a=nominal bolt diameter) – When overwritten the suggested lookup value will be shown.

  • Target Bolt Stress - If Flange Size or Class Rating is missing, IMS will suggest 70% of the Bolt Yield Stress at Amb Temp (if available). (IMS also calculates a Target Gasket Stress based on the Target Bolt Stress.

  • Tightening Method (dropdown) – the options are based on the Stud Size.

  • Nut Factor = K (range: 0-1). Note: This is also used for the integrity calculations (see below).

  • Bolting Tool (search functionality).

Note: Predefined Default values can be changed.

• Recommended Specs – Flange management recommendations:

  • Operating Temperature – this is inherited from the level 4 Equipment (if available). Note: Warnings are given if Recommended Specs are not aligned with the Operating Temperature.

  • Flange Type (dropdown) – default is "RAISED FACE"

  • Stud Coating (dropdown)

  • Flange Coating (dropdown) 

  • Stud Grade (dropdown) – default is "A193-B7". Note: Warning to "Review target bolt stress" is given if Stud Grades other than A193-B7 or B16 are selected.

  • Nut Material (dropdown)

  • Gasket Type (dropdown) – default is "SPIRAL-WOUND"

  • Gasket Material (dropdown) – available material depends on Flange Type

  • Gasket Material Addition Info

  • Lubricant (dropdown)

  • Heat Trace ("Yes"/"No") - If set to “NO”, IMS will auto fill “NO HEAT TRACE” for Heat Trace LOTO ID in the Specs Section.

  • Heat Trace LOTO – only shown if Heat Trace = "Yes"

  • Insulation ("Yes"/"No") 

  • Washers ("Yes"/"No")

  • Washer Type – only shown if Washer = "Yes"

  • Isolation (dropdown)

  • Drawing

  • Pipe Schedule

  • Pipe Wall Thickness - default based on “Flange Size”, and “Pipe Schedule” and lookup table ASME B36.10M-2018 - Welded and Seamless Wrought Steel Pipe.

  • Pipe Specification

  • Thread Series (dropdown) – default is "COURSE"

  • Isometric Number

  • P&ID

  • Bolt Length

  • Bolt A/F Size

  • Number Of Threads Per Inch – default based on Lookup values coming from ASME BPVC.II.D.M-2019 (see References).(You can click on the info button and go to lookup table in settings via the hyperlink)

  • Bolt Tensile Stress Area - A = (π / 4) (nominal diameter - 0.9743/number of threads per inch)². (You can click on the info button and go to lookup table in settings via the hyperlink)

Note 1: Predefined Default values can be changed.

Note 2: Where Lookup values apply, you can click on the info button and navigate to Lookup table (in settings) via the hyperlink. 

Note 3: If OTHER is selected from a dropdown, an additional field will appear where another option can be specified.

Several warnings can be displayed in this section, depending on data inputted:

• Warning if Flange meets critical joint criteria.

• Warning if Torque or Tension value is lower than calculated value.

• Temperature warning if studs are not suitable for operating temperature.

• Warning if Flange meets criteria for hot torquing.

Note 3: All lookup values can be reviewed in Settings \ Maintenance \ FCM Specific Data \ Lookup tables.

Integrity Calculations - Assembly Bolt Stress Determination

IMS FCM can also be used for joint integrity calculations. These calculations can help to assure the integrity of bolted joints in pressure equipment. The calculations provide Flange stress limits and checks that it can be used to ensure that a designed joint cannot be over-stressed and thus damaged. The calculations can also be used to determine the root cause of joint leakage, since it will highlight limiting components.

The basic principle of the calculations is that in order to avoid joint leakage, the joint must be assembled to a bolt stress level, which provides adequate stress to seat the gasket, adequate stress to provide sufficient residual stress on the gasket during operation, and also be sufficiently low such that no damage occurs to any of the joint components during assembly or operation. 

The following calculations are implemented in IMS:

• WRC538 – WRC Bulletin 538 Analysis – See Reference.

• ASME Section VIII - ASME Sec VIII Div 1 2019 App 2 – See Reference.

• PCC-1 - ASME PCC-1 Appendix O Analysis – See Reference.

Input the integrity calculations data on the Design tab:

• Click the applicable calculation’s button (top right) to highlight the applicable fields.

• Enter the data.

• Click Save when done.

Review the integrity calculation results:

• Click on the different calculation tabs (WRC538, ASME Section VIII, and PCC-1) to review the results.

• Use the calculations to maximize the Flange Bolt Stress (Sf_max).

Assumptions

• The Maximum and Minimum Bolt Stress (S_bmax and S_bmin) utilized in the PCC-1 calculations (Step 2 and Step 3) are assumed 70% and 40% of the Bold Yield Stress at Amb Temp (S_ya).

• The calculations use a constant related to the friction coefficient, called the Nut Factor (K). In most applications at ambient temperature K is approximately equal to the coefficient of friction plus 0.04 (i.e., 0.17 for uncoated studs properly lubricated with nickel-based anti-seize and 0.12 for Teflon-coated studs is used). However, this is a user defined value and you can specify anything between 0 and 1. You will find it under Tightening (step 2), since it is also used in the Torque calculation.

Flange and Bolt Material Lookup

Lookup tables (based on Operating Temperature, Flange Material and Flange Thickness) are used to determine the:

• Allowable Stress at Amb Temp

• Allowable Stress at Oper Temp

• Yield Stress at Amb Temp

• Yield Stress at Oper Temp

Lookup tables (based on Stud Size, Operating Temperature, and Stud Grade) are used to determine the:

• Bolt Allowable Stress at Amb Temp

• Bolt Allowable Stress at Design Temp

• Bolt Yield Stress at Amb Temp

Note 1: The lookup values can be reviewed in Settings \ Maintenance \ FCM Specific Data \ Material lookups. You can also just click on the info button of a specific value and then navigate to the applicable Lookup table (in settings) via the hyperlink. 

Note 2: For the fields with reference to the Ambient Temperature, values for the lowest temperature in the lookup table is suggested.

Note 3: When no lookup information is available, IMS will show a warning.Flange Material and Bolt Material fields are populated based on lookups. 

Locking Flange Design

If you do not want your flange design to be edited by others, you can Lock your flange design. By locking a flange design, only you can edit it. This functionality is available for the FCM ADMIN and FCM GENERAL roles. The FCM ADMIN role can override the lock of others but other roles will not be able to change the flange design.

To lock the design:

• Click the blue Lock icon.

The lock icon will turn red to indicate that the design is locked.

To unlock a Flange Design:

• Click the red Lock icon.

The lock icon will turn blue to indicate that the design is not locked.