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  • Users: Rubje
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  1. Rubje

    Wrong Tensile Strength on 2 different U1A

    Hi all, A client of mine has two ASME VIII stamped pressure vessels made by different companies in the 60s. Both are made of SA-7 and what puzzles me is the Tensile Strength on each vessel is 55k but the code says there is a 0.92 quality factor thus giving an allowable stress of 12,650 psig...
  2. Rubje

    API-ASME: 579: General vs Local Corrosion

    579 doesn't draw a clear distinction between general(part 4) and local corrosion (part 5) Any guidance on how I can determine which part (4 or 5) to use depending on the situation? thank you
  3. Rubje

    Have you ever seen a 3:1 ellipsoidal head used on a vessel?

    I only seen the standard 2:1 ellipsoidal head used on vessels and I'm curious if anyone seen any other ratio used before. If so, what was the reason why that particular ratio was used and not 2:1?
  4. Rubje

    Piping Considerations for Pipeline with Sand Erosion

    I'm working with a client that is dealing with high erosion rates due to sand in the well. I'm brainstorming some piping changes that can be made to decrease to erosion rates. Here they are: -Avoid 90 elbows and rely on 45 elbows -Size piping to have a flow velocity less than 10 m/s -Avoid...
  5. Rubje

    ASME VIII 1943 Sections U-68 and U-69

    Hi All, In the 1943 year of ASME VIII they list two different joint efficiencies to use for non-seamless components in U-68 and U-69. It's not clear which one I should use. I tried reading U-68 and U-69 and it doesn't make sense. Any help is appreciated.
  6. Rubje

    API-ASME 1943 code?

    I found a document that says API-ASME 1943 and then i found one that ASME 1943. While there are many similarities I notice the minimum thickness equations and efficiency values are different. How do I know which one to use? anyone know the history behind this?
  7. Rubje

    ASTM A7, A30, A70

    Hello, I'm having a very hard time finding the chemical composition requirements for these 3 obsolete material specs. Does anyone have a source or know the answer? thanks
  8. Rubje

    UG-46 requirement for vessel

    Hi everyone, We are having a vendor fabricating a 48" dia. vessel for us. We have an issue with a manhole for inspection purposes. According to ASME VIII UG-46; all vessels greater than 36" in diameter shall have a manhole, except when the shape of the vessel or use of a manhole is...
  9. Rubje

    Concerns about ASME B31.3 Socket Welds

    There appears to be a recent change (2022) to 328.5.2e. It now says the following: "In making socket welded joints, a gap as shown in Figure 328.52b, illustration (c ) and Figure 328.5.2C shall be provided prior to welding. After welding, a gap is not required to be present or verified" I...
  10. Rubje

    Pressure Control in two-stage refrigeration system

    I have a system similar to the one in the image above. It's a two stage mechanical refrigeration unit with a flash economizer, using propane as a refrigerant to cool a process stream. The compressor is a screw compressor, so positive displacement. If I'm understanding this system correctly, the...
  11. Rubje

    B31.8 vs B31.3: Toughness Requirements

    In the following thread: thread378-116351 I saw this post by SJones: "I don't think that there will be a problem as the design factor in 31.3 is lower than B31.8. However, B31.3 may not address Charpy toughness testing in the same manner as 31.8 (in the sense that 31.8 demands the designer to...
  12. Rubje

    AP 510 Section 9.3.3.1 c (2014)

    Hello, 9.3.3.1 c says the following: "calculations in accordance with the requirements of the construction code to which the pressure vessel was built or by computations that are determined using the appropriate formulas in the latest edition of ASME code, if all the essential details comply...
  13. Rubje

    Examples of failures due to Mechanical integrity or Inspection Issues

    Besides CSB, I'm looking for more examples and case studies of a failure/accident in the oil, gas and chemical industry that was due to a poor integrity program and/or inspections.
  14. Rubje

    What fluid state to use when sizing a Relief Valve for a fire case if the shell-side fluid is steam?

    Context: -We are trying to add a Relief Valve to protect the shell-side of a shell and tube heat exchanger -The over pressurization scenario for the exchanger is the external fire case. -The shell-side fluid is steam which gets condensed. The exchanger is equipped with a steam trap to...
  15. Rubje

    PSV lifted below Set Pressure

    We have a PSV on a boiler that is set to lift at 465#. It lifted at 465# (process upset). It lifted again about a week later at only 430#. We assumed it had an issue after the first lift so we removed it and shop tested it, expecting to find an issue. Upon removal we didn't see anything that...
  16. Rubje

    Determining Material Spec

    We are expanding the chemical unit I’m working at to increase production. It’s going to be a combination of buying new equipment and using vessels that have been out of service. There is this one particular vessel that we used only for about a year back in the 80s but it hasn’t been used since...
  17. Rubje

    Improper Installation of PSV

    All, CSB released the final report the Ethylene Release and Fire at Kuraray America, Inc. EVAL Plant. One of the contributing factors that made this incident worse was that the PSV had a tail pipe that was installed in a horizontal position which ended up released flammable vapor towards an...
  18. Rubje

    New MI Engineer

    Hi everyone, I recently switched over to the Mechanical integrity (MI) group where I will be focusing on integrity engineering of pipes, vessels, etc. Besides reading the codes such as API 510, what other reading or learning material do you recommend? It's hard to find good youtube videos on...
  19. Rubje

    Calculate required thickness for Plate and Frame heat exchanger and fin fin header boxes

    HI all, It looks like ASME VIII only gives guidance calculating minimum wall thickness for cylindrical equipment like vessels and piping. How can I determine the minimum thickness required for the header box on Air Cooled Heat Exchangers? How about plate and frame heat exchangers? We are...
  20. Rubje

    IRIS on Heat Exchanger tubes

    hi all, I had two different contractors perform IRIS on one of my heat exchangers. Their data and findings are very different. Any suggestions on how to move forward with this? our budget is limited so contracting a third technician may not be doable. What questions should I ask them to...

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