Methods for flange leakage checking by Pressure Equivalent Method using Caesar II

Few days back I had published a post on Methods for checking flange leakage. In that article the I had mentioned the theoritical background (analysis criteria, basic theory behind flange leakage checking, analysis methodology etc) for checking flange leakage. So click here to refer the article once again before you proceed on this article. In this current write up I will explain the step by step method for performing flange leakage analysis methodology following Pressure Equvalent Method using Caesar II. Click here to check the ASME Section VIII method.
Fig. 1: Typical flange in Caesar II model
Caesar II methodology for Pressure Equivalent method:
  • Model the stress system from stress isometric. After modelling is complete select the flange which need checking as per pressure equivalent method. In Fig. 1, node 20-30 and node 30-40 denotes the flange assembly. And flange leakage checking is required for node 30.
  • Now select the Flange Node(From/To/Both) and Calculation Type as shown in Fig. 2.
  • Select Flange Class/Grade through ‘Read from File’ button and refer to ASME B 16.5/ ASME B 16.47 material tables.
  • Required data will automatically be filled. By default the value of G will be taken as the mean gasket diameter. User to update the value of G as per ASME B 16.20 & ASME Sec. VIII Div. 1, Appendix 2, Table 2-5-2. based on following equation:
    • b0 = 1/4, G = Mean diameter of the gasket contact face
    • b0 > 1/4, G = Outside diameter of gasket contact face less 2b, b=basic gasket width from code. check the above mentioned link for details.
Fig. 2: Caesar II Spread sheet typical input
  • Now go to the load case editor and select the temperature at which flange leakage checking to be performed as shown in Fig. 3. Now run the analysis to check the results. In case the generated stress exceeds the allowable results will be shown in red colour. Check Fig. 4 for output results.
Fig. 3: Load Case Options module in Caesar II
                                   Fig. 4: Caesar II flange leakage pressure equivalent output 
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Anup Kumar Dey

I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.

6 thoughts on “Methods for flange leakage checking by Pressure Equivalent Method using Caesar II

  1. Dear Sirs,

    Thank you for this reference, as currently I am calculating this Pe using caesar but why caesar using force perpendicular to my axis instead of axial force, let say my piping is in z direction (as axial = Fz) but caesar using force Fx for this calculation?


  2. Hi Anup
    When i model a valve or flange use Cadworx database, the dimension and weight of valves/flange different with vendor data. How can I create an other databases for valves/flange or modify the database of Cadworx (I modify the cadworx catalog in C:\ProgramData\Intergraph CAS\CAESAR II\5.30 but the dimension and weight of valves/flange didn’t change in model)

  3. Dear Sir/Madam

    your website is so informative and I appreciate it.
    in this article figures 2~4 have not loaded and I was wondering if you could send me these figures.

    thank you in advance.

  4. GRP piping and metal lap-joint flange check

    i have a GRP system and lap-joint flanges (metal flanges and GRP stub-end).

    The flanges connect the two stub-ends and between every couple of metal flange there are the two GRP stub-end ends, so metal flange don’t connect direcly, there is GRP between them.

    How to perform flange check in this situation?

    thank you

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