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  1. dig1

    Pressure vessel internal and external corrosion - effective as one side corroded vessel ?

    Hello Mariolucas, I think the best way to look at this is to determine if the remaining thickness is less than the required thickness (by calculation). Depending on the Post Construction Code/Jurisdiction/etc. there may be additional requirements which will be written in those documents. This...
  2. dig1

    Versions of ASCE 7 for Section VIII, Division 1 Vessels

    Thank you AWDMIKE, Fortunately we are doing both the vessel design for the fabricator and the foundation design so it is easier to handle the engineering aspect. Both the building code and ASME have what I consider equivalent legal standing in this instance. Maybe for the 2025 edition of the...
  3. dig1

    Versions of ASCE 7 for Section VIII, Division 1 Vessels

    I'm wondering if anyone else has run into this situation. Currently designing a vessel to the 2023 ed. of Section VIII, Div. 1. Table U-3 states that ASCE 7-22 be used. The jurisdiction where the vessel is going has adopted IBC 2018 (w/ some State specific amendments that do not apply for this...
  4. dig1

    PV-Elite flat bottom tank

    Europeeng, I don't think it can be done correctly. The flat head, as has been mentioned earlier, will not be calculated correct so it will show as failing under internal pressure. You could build the model w/ a welded flat on the bottom and then attach a shell and use lugs on the shell. Unless...
  5. dig1

    PV-Elite flat bottom tank

    It really doesn’t work for what you want. I’ve tried a long time ago. JStephen is correct. Would EN 14015 be more appropriate? If the tank is pressurized to any extent the shell to bottom joint and anchorage needs to be looked at in detail.
  6. dig1

    Clarification for Warning in PVElite

    SmallInfo, I just ran a very quick model w/ SA240-UNS S32205 (ASME Section VIII, Div. 1, 2021 edition) where the design temperature for internal pressure was -20F and the external design temperature was 500F. The S value for internal pressure was correct and for the external pressure 'B' value...
  7. dig1

    Vessel Design and Analysis

    Alk2415, HTURKAK brings up great points. As a STAAD user I would not design a pressure vessel, with respect to local stress analysis, with STAAD. When looking at local stresses for this type of vessel designed to ASME the rules of Section VII, Division 2, Part 5 Design by Analysis is the proper...
  8. dig1

    (Temporary) Stiffener Sizing for Boiler / Tower cut out.

    ER Azza, You may want to look at Tubular Steel Structures Theory and Design by Troitsky; there are sections on on the analysis of breech openings including the stiffener design; it may not be 100% applicable to your situation but you should be able to adapt the methodology. Typically when we do...
  9. dig1

    HP 15c re-release, Anyone still using calculators

    I still use an HP11c and HP-41CX daily. Not for programming but I have used them since the mid-1980s. The 11C and 15C are actually great to take in the field because they fit easily in a shirt pocket and you can always run a quick number. Almost all of our field work is in industrial plants and...
  10. dig1

    Weathering Steel vs HDG

    Ideem, We do a lot of work in mining and waste-to-energy (WTE) plants. The ash is generally stabilized with lime and is wet and hangs to everything. Our experience is that, in general, a properly specified and applied 3-coat paint system holds up very well. HDG does not hold up more than a few...
  11. dig1

    position of hydro test

    saravanan.E. I don't know if this interpretation helps answer your question; I remember when this was issued. "Subject Description: Section VIII, Division 1 (1992 Edition, 1993 Addenda); UG-99(b) Date Issued: 01/12/1995 Record Number: BC94-414 Interpretation Number : VIII-1-95-27...
  12. dig1

    Actual vessel thickness greater than nameplate

    Geoff13, Thank you; this makes sense to what I have seen on older drawings and ties into with what I have been told before.
  13. dig1

    Actual vessel thickness greater than nameplate

    LittleInch says what I have seen on older vessels as well (1960s vintage) on the shells and heads. Heads I can understand more, especially in the "spherical" portion of 2:1 elliptical. What I was told by a long retired and now deceased CB&I engineer is that first the plate thickness always ran...
  14. dig1

    MDMT temperature

    static engineer 07, The required MDMT is a user input and information on that is in UG-20(b). The required MDMT may be related to the surroundings but is most likely process driven. Again, please read UG-20(b). Please study UCS-66. As GD2 stated the Curve for the SA105 depends on the condition...
  15. dig1

    MDMT temperature

    Static Engineer 07, The MDMT would be an input. I believe it is on the "Design Constraints" tab on the lower left and is under "Miscellaneous Design Data". The specifier of the vessel needs to make the determination of the MDMT using the definition in UG-20, assuming Div. 1. I hope this helps.
  16. dig1

    Structural height on ASCE-7 seismic calculation

    ftoran, You have taken the definition from Chapter 11. You are likely in Chapter 15 but possibly Chapter 13. In Chapter 15 Table 15.4-2 the structural heights are no limit (NL) for skirt supported vessels. Is the question over the mass distribution? I've been designing vessels for over 30...
  17. dig1

    Opinion on IDEA statica - connection design software

    Canpro, You responding while I was writing. Great points.
  18. dig1

    Opinion on IDEA statica - connection design software

    waren1991, Great question. We perform FEA regularly but mainly for pressure vessels using ASME Section VIII, Div. 2, Part 5. While my comments are skewed in that direction we also do a fair amount of structural steel work mainly for non-building structures. I also prefer manual calculations...
  19. dig1

    Seismic Calculations in Compress Without Supports

    Did you try making the bottom a welded flat and attach the lugs to the shell? You will undoubtedly fail the bottom but it may work. Is the tank/vessel mechanically or self-anchored? Why don't you simply write a spreadsheet or do hand calculations? I strongly dislike the type of work around I...
  20. dig1

    Responsible Charge and Independent Contractors

    There is a Administrator's Interpretation No. 2015-1 - BLR which helps clarify or perhaps muddy the situation https://www.blr.com/html_email/ai2015-1.pdf Typically if we hire a 1099 person (typically out-sourced drafting of red lines) they work for multiple clients, tell us when they are...

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