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Recent content by GD2

  1. GD2

    Determining flow through a half full gravity return oil line

    1. For gravity drain, the pipe size and the flow rates are matched to the available energy. The available energy is the elevation difference (termed head) between the supply and delivery points. For maximum natural flow, the available energy equals the friction loss in the pipe. You can choose a...
  2. GD2

    When would piping need to be replaced due to an overpressure event where the Yield Stress was exceeded?

    Wait a minute. How a stress analysis or hydrotest will tell that YS is exceeded or not exceeded? And wasn't the piping protected for overpressure? By Code, it should be. In the context of overpressure, I would assume that the system had exceeded the design pressure. If you are talking of...
  3. GD2

    A333 Gr 6 Minimum Temperature

    Remember, the calculated stress ratio is the greatest of the three stress criteria given in ASME B31.3 Fig. 323.2.2B. The 3rd criteria is essentially the equivalent Primary and Secondary load criteria in PV design. For displacement loads, you should include thermal, restraint movement and...
  4. GD2

    Bolt Torque and Bolt preload query

    Hi Dan, The key to find your answer is follow Appendix O and determine Sbsel following Joint Component Approach O-4.2. Integrity of a flange joint is dependent on integrity of all the assembly components - the flange, gasket and bolt. Para O-4.2 is a stress check for all the components both at...
  5. GD2

    Piping Class Design relationship with PED

    PED 2014-68-EU is for stationary pressure equipment. PED had recognized and accepted ASME B31.3 - process piping code indirectly through two supporting documents: ISO 15649: Petroleum and Natural Gas Industries - Piping. EEMUA Publication No. 202: Guide to the use of ISO 15649. These...
  6. GD2

    Flare line connection

    The Code will not tell you if you can tie-in to a flanged connection or not. Many Owners will have their own specification not allowing flanged connections to a flare header - the reason being - to avoid ingress of air/oxygen to form a combustible mixture with the vented/flared gas. Of course...
  7. GD2

    Bolt Torque and Bolt preload query

    Dan, The key to keeping the appropriate bolt preload at both ambient (installation) and operating condition (500C) is to determine the bolt stress (Sbsel) is as per Appendix-O. O-4.2 will take you through all the checks at both ambient and operating conditions for the flange assembly - bolt...
  8. GD2

    Creep design - EN 13445

    You should revisit your design. The top part of 310S you said will be operating at creep (650-675C) and 100,000 hrs. (say 12 operating years ). One of the things designers overlook is the design life when taking stress values from BPVC Sec II Part D. For vessel that predominantly operates in the...
  9. GD2

    Ring Joint Flanges for 38 inch and larger size as per ASME B16.47 Series A

    That's the direction I would go in absence of any dimensions not found in a standard (example ASME B16.47) acceptable to the construction Code - qualify by Sec VIII Div1 Appendix 2.
  10. GD2

    ASME B31.8 831.4.2(c) vs. 831.4.2(j)(3) - Reinforcement members and Pressurized Sleeves, End face thicknesses & fillet welds

    You should treat B31.8 831.4.2(c) and 831.4.2(j)(3) separately for understanding. Whereas 831.4.2(c) talks about a complete encirclement reinforcement type that we encounter in daily life, 831.4.2(j)(3) talks about hot tapping/plugging fittings, where the reinforcing sleeve is pressurised and is...
  11. GD2

    Very High Temperature Piping Stresses

    I will be a bit skeptical on the 1200C. What is that process that uses 1200C? Furnace heater tubes goes upto 900C and the high temperature nuclear reactor cores made of graphite materials. Typically Ni-Fe-Cr alloys can see the max temperature. If you are talking about Pyrolysis process, users...
  12. GD2

    Pipe Wall Thickness Calculation - EN 13480 Part 3

    Sorry, I am not used to EN standard. I am an ASME guy. I can’t therefore validate your strength numbers. As for creep, it is when the material time-dependent properties kicks-in. Examples are heater tubes where the tubes has to be designed for both elastic and rupture (creep). If you haven’t...
  13. GD2

    Pipe Wall Thickness Calculation - EN 13480 Part 3

    Why do you even have to do the time-dependent evaluation? CS @204 C will never cross to the creep regime. Temperature limit to define the creep range for EN 10217-2 Gr P235GH material will be 343C-371C depending on the reported tensile strength.
  14. GD2

    Minimum pipe length for Process Vent

    There is no standard available. You have to make one for your company or the project. Process vent should be a proper vent assembly with valves that will be used for the life cycle of the plant during start up, shutdown, maintenance etc. It should be based on the piping class. Different vent...
  15. GD2

    B16.5 Max Flange Hydrostatic Test Pressure

    If I am reading/interpreting B16.5 P8.2.2 correctly, CL150 reads 20 bar (290 PSI) at 38C X1.5 =30 bar (435PSI) max flange pressure. Or would it be 21 bar? The test pressure would be 450 psig rounding off to next higher 25 psig. It's the max test pressure. However, note that you won't be only...

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