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  1. akpipelineengr

    Pressure vessel under negative Pressure

    Composites don't do great in compression. Just because it hasn't failed yet, doesn't mean you aren't accumulating damage. Titan_submersible_implosion
  2. akpipelineengr

    Tie-In Issue: 10”x10S SS316L to 24”x10S SS316L – Weld Clearance & Flange Type

    Neither option leaves any room for bolting those flanges or making the necessary welds, let alone the stress concentration issues (in Sch 10S!). There has to be a better way. Move the tie-in up- or downstream to where you have some real pipe to work with. Use an appropriate branch connection.
  3. akpipelineengr

    Practical Implications of Impact Testing

    Yes, but it is possible. To your example of A333 Grade 6 at -55F, it is simply a matter of specifying additional testing and ensuring you have the material to test. The manufacturer may be able to just lower their test temperature, but only if you are buying in large quantity. More typically...
  4. akpipelineengr

    Tangential Radiography of 16" pipe

    The typical application of tangential radiography is for external corrosion, particularly CUI. You aren't looking for penetration of the steel, only the insulation around the pipe. This gives you a tangential view of the pipe surface, from which you can see CUI damage due to the expansive...
  5. akpipelineengr

    What is the P&ID symbol of a double block and bleed valve (DBB) (Not two independent valves and a bleed valve) ?

    We use symbols like these for single body DIB valves.
  6. akpipelineengr

    Natural gas pipe temperature

    By running multiple cases and determining which gives you the largest diameter.
  7. akpipelineengr

    B31.4 Existing Pipe is Overstressed -what's the path forward?

    He says it fails occasional stresses, so I'm guessing that because it is not adequately anchored, when you model the line, the wind and/or seismic cases cause gross displacement of the line resulting in overstress. "Inadequate support" may also mean that spans are too long and you're getting...
  8. akpipelineengr

    Natural gas pipe temperature

    What kind of gas? What kind of pipe? Do you have a design code? How long is the pipe? Design temperature is important, but we're going to need a lot more detail from you.
  9. akpipelineengr

    B31.4 Existing Pipe is Overstressed -what's the path forward?

    What is "required" depends entirely on the owner's requirements and any applicable regulations. In general, you don't have to go back and bring the line up to meet current code requirements, but you do need to determine if any of the issues you have identified are fitness for service issues...
  10. akpipelineengr

    Piping Material Grade Query

    B31.4 does not consider the manufacturing tolerance separate from design factor. 0.443" would be the Code minimum wall thickness, exclusive of any corrosion allowance. Refer to para. 403.2.1: "In setting design factor, due consideration has been given to and allowance has been made for the...
  11. akpipelineengr

    Piping Material Grade Query

    What is the design code? Assuming design pressure is 1480 psig, 0.500" wall thickness is thin in the low yield flange material, but how thin will depend on your design code.
  12. akpipelineengr

    End Face Dimension - ASME B31.8 831.4.2(j)(3)

    ASME PCC-2 is written a little more clearly for the design of pressure sleeves. Refer to Figure 206-3.5-2. I would do your pressure containment calculations as you have for example 1. Note that that if your fitting has a long seam weld, your weld efficiency of that seam will be based on your...
  13. akpipelineengr

    pressure test piping of natural gas 150 Barg by N2

    @GD2 What am I missing? Try running the numbers here. If we assume this is a B31.8 pipeline, the maximum design pressure is ~875 psig, assuming the highest allowable design factor of 0.8. That results in a hydrotest pressure of 1094 psig, which is about half of the proposed test pressure here...
  14. akpipelineengr

    pressure test piping of natural gas 150 Barg by N2

    Am I missing something? That hydrotest pressure on that grade of low yield pipe results in hoop stress almost double the yield strength. This looks like a bomb to me. What is the design pressure? What is the basis for the test pressure?
  15. akpipelineengr

    Carbon Equivalent Number for different steel

    https://en.wikipedia.org/wiki/Equivalent_carbon_content
  16. akpipelineengr

    Acceptable tolerance for surface defects on pressure piping

    Start with the design code. Then perhaps API 579.
  17. akpipelineengr

    Pig Kicker line size

    Those main line and kicker line sizes are in the range that I've typically seen. I've seen operators' specifications limit the kicker to no less than 1/4 of the main line diameter (so DN 50 for your DN 200 main line), and many installations are larger than that. You'll need to check fluid...
  18. akpipelineengr

    Jacketed Gaskets and ASME B16.20

    I'm guessing you are looking at an old version of B16.20 and a newer version of B16.5. The reference only works if you refer to B16.5 from around the same time as the version of B16.20 you are using. Consider using a current version. Both standards have been significantly revised.
  19. akpipelineengr

    ASME B31.3 2018 - Minimum impact test exemption temperature reduction

    I interpret condition 3 to require action to prevent impact loading, if you are going to take credit for that reduction. That may mean removing small bore valves from the system or taking administrative action (like car seals) to prevent impact loading at cold temperatures, as well as guarding...
  20. akpipelineengr

    Underground Oil & Water Pipelines

    Could you elaborate on your pipeline? Pipeline details like size, wall thickness, material grade, design code, design pressure, environmental conditions, and fluid properties would all be helpful to understand your request, as well as corrosion rates observed, corrosion inhibition, details of...

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