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  1. nashof

    Pressure Equipment Directive

    ASME is of course an accepted code by PED, but as it was said in this post, if you design using ASME VII for example you will have some additional requirements. However, there are certain rules that are considered "Harmonized", so, if you use them as your design code the compliance with PED is...
  2. nashof

    PWHT UCS-79(d)

    I suppose if you use a CAP (234-WPB) that would be done using hot conforming, and in that case PWHT would not be neeeded. Can anyone confirm?
  3. nashof

    ASME section VIII div.1 2,3

    tananT.... Your question is toooo much "easy" for a tooo much "difficult" question.. I suggest you try to find good information in internet, books, manuals, reading ASME codes, and asking more expert engineers.
  4. nashof

    Material of Construction for -46 deg C

    rkdpv, You should check with ASME VIII Div.1 (with the assumption you're talking about pressure vessel). In UCS-66 you can check, because it depends of the thickness. For 20 kg/cm2 I think your thickness will be more than 15mm (of course it depends on the dimensions on the vessel..) so you will...
  5. nashof

    The minimum allowable temperature for SA 516-70N

    JStephen is right. It dependes on the application, I was supposing your question was for a pressure vessel.
  6. nashof

    The minimum allowable temperature for SA 516-70N

    You should refer to ASME VIII Div.1 UCS-66 to see if impact test is required (Curve D for SA-516 Grade 70 Normalized) Generally carbon steel is no "adequate" for temperatures below -29ºC (-20ºF), but SA-516 if normalized has good working below that temperature. For example, if temperature is...
  7. nashof

    Extra Stud (Size>1 1/2") Length For Hydralic Tensioner

    For your first question, I think a good practice would be to have a extra length of One Diameter in the whole bolt.
  8. nashof

    Two Legged supported Vessel

    FrancKx, I don't think that will be a good design, but maybe you could calculate it correctly and demostrate it will be ok. Is it possible to use LUGS instead of LEGS? With that design it would be easier to calculate the use of two supports.
  9. nashof

    Fatigue Analysis - AD-160

    Thank you all for your help. I couldn't find any information in order to know which number should be consider for temperature variation. I will contact an expert about this, becasue I'm not in the position to decide, but I find strange that nobody has experience with this so to know if the...
  10. nashof

    Fatigue Analysis - AD-160

    Thank you for your quick responses! Maybe I was wronk, but I thought ASME VIII Div.2 Ed.2007 was not complusory at this moment. I also think my vessel will need a fatigue analysis, but I wanted to know how to consider the temperature changes I have previously told (from 20ºC to -170ºC). In ASME...
  11. nashof

    Fatigue Analysis - AD-160

    Hello All, I have two doubts regarding cyclic service / fatigue analysis thay I can't understand, and I'd be very pleased if you could give me a hand: 1- The vessel (horizontal drum, thickness 1/2")has temperature cyclic service. The vessel is at ambient temperature (20ºC = 68ºF), and when the...
  12. nashof

    Question regarding Sec VIII Div 1 and closest approach welds can have

    I don't find specially strange that a pad covers a seam, as weldtek sayed. You should revise your client specifications, because it is quite common that include something about it. For example UOP specifications, which quite a good reference for all petrochemical projects, asks to have 3"...
  13. nashof

    Vessel on Two Lugs

    Hello All, I am currently designing a small vessel, which needs to be supported on lugs, and I have a doubt. The vessel dimensions are Tl-TL 2000mm aprox 79") and diameter 600mm (24"). MAterial SA-240 304, the same as lugs. Due to piping needs if we install it on four lugs it's really difficult...
  14. nashof

    Leak Test on Branches Reinforment Pads

    Good point, gr2vessels. I've found a maximum of aprox. 15 PSI a usual practice. Some clients specify a minimum of 6 PSI. I think a pressure between 6 and 15 PSI are good values, and enough to know if pad is ok. Cheers,
  15. nashof

    Maximum Length for LWN

    Thank you for all the comments! 9" and 12", as DG72 is saying, I think are most common lengths. Our LWN are stainless steel (SA-182 Gr. F304L) and they need to be LWN or self reinforced WN, as the vessel is in cyclic service. Do you consider if the vendor considers difficult to find (or the...
  16. nashof

    Maximum Length for LWN

    Hello All, Could someone confirm me if there is a maximum length for long weld necks? The client is asking for a vessel in cyclic service to provide self-reinforced nozzles for those bigger than 2" and LWN nozzles for 2" and less. (Something quite usual). The problem is this vessel will have...
  17. nashof

    Leak Test on Branches Reinforment Pads

    Just one opinion to add, Some client specifications ask yo provide one drilled hole (1/4" npt for example) for pads in nozzles through 12" and two drlled holes hor nozzles bigger that 12". What pressure do you consider good fot the test? Some clients specify 0.4 kg/cm2 (aprox 6 PSI).
  18. nashof

    304 versus 316

    For cryogenic service I agre with unclesyd: 304 has better properties than 316, but the difference is so small, that I think that the main reason which makes 304 to be used for cryogenic service is the money. For cryogenic service (typical LNG or LN2) corrosion is not a problem (usually) so both...
  19. nashof

    Vessel in Cyclic Service

    Thank you for your opinon yl0525! My doubt about wich temperatures should we study was because in the inner wall of the vessel temperature will change from -170 to 100, and in the ouside wall it will change from 200 to ... (I'm not sure what temperature). My company, as you said, will not...
  20. nashof

    Vessel in Cyclic Service

    Thank you very much for all the responses! The MDMT is -170ºC, which corresponds to LNG going into the vessel, once the LNG is in the vessel we have an electrical heater in lower outside part of the vessel which gets 200ºC and heats the LNG to a temperature of aprox. 100 ºC, and then it goes to...

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