Flanged Fitting

[Mike4321]

I am trying to get a flanged fitting certified to ASME B31 Process Piping standard and am having some confusion with paragraph 302. On the fitting one end is flanged and the other has a threaded JIC end.

The fitting is one solid machined piece. In 302.2 it mentions listed and unlisted components. Do I treat the whole piece as a unlisted component and then do an stress finite element analysis or do I treat the threaded end and flanged end as components (which conform to SAE and ASME standards) and still do a finite element analysis to show the pressures the whole piece can withstand.

Sorry if this is a dumb question. I've just finished school and started a job and am finding these certification codes confusing.

Thanks,
Mike4321

 

[Mike4321]

Thanks for the help

 

[deanc]

Mike4321-You appear to be unhappy. Perhaps your question was not clear enough. There are some really sharp people that respond on this group. I have learned alot myself and have a great deal of respect for alot of them.

Have you talked to your AI about this? I think you will need to justify the entire part. FEA may or may not be acceptable. You may need to calc.this out. Take a look at SecVIII Appendix 2 for some guidance.

 

[Mike4321]

Thank you deanc. I was looking for guidance, like you gave, to get started because these codes seem a little overwhelming at first.

Here is some more information:
The adapter is for the lube and scavenge pump on a gas turbine. It is attached using the stock bolts and gasket from the turbine for the flanged end and a JIC-12 crimped hose connection on the other.

There are actually three that I am trying to certify (for three different turbines). Two have four bolt flanges (the dimensions of one conforms to a military standard) and the third is a three bolt flange.

So far I've done an FEA analysis for an internal pressure of 500psi (the max designed pressure, even though the pressure in the lines is nowhere near that) and the stresses within the adapter fall well below the allowable stresses outline by B31.3
I've also gone through the code (most of which doesn't apply because it is for whole systems) noting any comments or information for the adapter to show its conformance.

The flanged end of the adapters are identical to the connection already used on the turbine. Two of these adapters have been in use since '99 and the three bolt for about six months (with no problems of course).

Will the Section VIII Appendix 2 calculation be necessary for B31.3 certification? (I believe it only mentions the Section VIII, Division2 Appendix 4, Article 4-1 for documenting the FEA results in the B31.3 code)

Any help or advice is greatly appreciated.

 

[deanc]

Mike-You need to design to the Code you build to. The reference to SecVIII is only for an accepted calc.for help.
Perhaps write-up what you have said here and run it past the AI. Sounds like you have done your homework. He may buy off on it.

 

[bvi]

The first question is whether it is a listed or unlisted component. A listed component is a component that is in accordance with one of the standards listed in Chapter IV of ASME B31.3. These include, for example, B16.5, B16.9, etc. These normally will have a stamp on them, from the manufacturer, indicating that they are in accordance with these standards.

What you have is an unlisted component. So, following the Code, you have arrived at 304.7.2(d) and qualification by FEA. You would qualify the entire component for pressure design in accordance with 304.7.2. Note that, with an unlisted component, you did have the option of using the other design rules in 304 if you determined that the composition, mechanical properites, method of manufacture and quality control are comparable to the corresponding characteristics of listed components (see 302.2.3). Note that the rules would have to apply; for unusual shapes, etc, one would need to go to 304.7.2 in any case.