Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hydraulic Fitting - Max Temperature

  1. Jun 16, 2008 #1
    Customer of mine is wanting me to confirm that a hydraulic fitting I am selling him will withstand 800F. The fitting is a standard issue hydraulic fitting (#12 BPP Female Coupling) that will be welded to 6" SHD 80 pipe. The pipe is on the exhaust side of a diesel engine onboard a cruise ship. No real pressure to speak of because it's venting to atmosphere. I haven't had much luck finding a clear cut answer. Since i'm in bearings and PT now I don't have the same contacts I use to. Any ideas?
  2. jcsd
  3. Jun 16, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I've never heard of a #12 BPP, but if this is a US application, the stress allowables for the material from ASME B31.3 at the given temperature apply unless there's a specification for the fitting such as an MSS spec. Note that pressure on a vent header is just one consideration. Bending moments imposed by the venting of fluid are another consideration, so simply saying there's no pressure load is misleading.

    In Europe, there's an equivalent pressure code, but I'm not familiar with it.

    If this is US, provide the ASTM material spec, grade and temper and I can see what the code gives for stress allowable.

    Once you have that, you can either do calculations on the wall thickness (you'll need to post a drawing) or you can derate the component by using the stress allowable at temperature divided by stress allowable at ambient times the pressure rating at ambient (assuming you have a pressure rating at ambient).
  4. Jun 16, 2008 #3


    User Avatar
    Science Advisor

    Last edited: Jun 16, 2008
  5. Jun 16, 2008 #4
    Yep, 3/4 Brittish Pipe E/E. Will have to look up the Parker number, I don't remember any of the nomenclature for anything other than pipe, JIC, or OFS.
  6. Jun 16, 2008 #5
    I'll try to find an available drawing and post, but most of the informaiton out of the cats won't have anything besides the configuration of the adapter. I knew I should of just told this customer I don't handle anything fluid power anymore. Me and my award winning customer service.:tongue:
  7. Apr 7, 2009 #6
    I am having problems to locate the standards for hydraulic piping up to 300 bars accoording to ASME B31.3.
    Here on sight in Brazil the main contractor wants to use sleeves to join the pipes together and weld them as a filled weld.
    can they do that and where do i find these standards in ASME.
    Thanks for your help.
  8. Apr 8, 2009 #7


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    See ASME B31.3, para. 306.1.

    "Listed Fittings" per para. 306.1.1 cover standard fittings (ex: elbows and tees) such as socket weld fittings per ASME B16.11 and buttweld fittings per ASME B16.9. These would be most like the fittings you're describing but since they meet the ASME standard, you can be sure of the pressure rating without doing calculations.

    "Unlisted Fittings" per para. 306.1.2 would cover the fittings you describe that consist of a sleeve with fillet welds. If you use an unlisted fitting as you're proposing, it is incumbant on the system owner to prove the fitting meets the piping code.

    Generally, I'd suggest simply butt welding pipe together as this is considered the strongest method of joining pipe.

    Don't forget about radiograph and leak testing of your system.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook