ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
(OP)
Hi everybody!
I need to carry out a very accurate verification about flange leakage.
Instead of using tables 2-7.2. 2-7.3, 2-7.6 to find flange factors F, V, f it is possible to use formulas in table 2-7.1.
The problem is that I obtain right values of factor f, but unreasonable values of F and V comparing them with figures above mantioned. Has anyone experienced the same? Is there an error comprised within constant C37 and E6?
My calculation has been executed by means of a calc worksheet.
Thanks,
Marco
I need to carry out a very accurate verification about flange leakage.
Instead of using tables 2-7.2. 2-7.3, 2-7.6 to find flange factors F, V, f it is possible to use formulas in table 2-7.1.
The problem is that I obtain right values of factor f, but unreasonable values of F and V comparing them with figures above mantioned. Has anyone experienced the same? Is there an error comprised within constant C37 and E6?
My calculation has been executed by means of a calc worksheet.
Thanks,
Marco





RE: ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
Refer to ASME PCC-1 (the new version just came out) for guidance on how you should be handling flange in the field.
If you are still convinced that you need to do a then I would recommend that you either someone who has extensive experience in troubleshooting flanges, extremely experienced in FEA of bolted flange joints (very very rare, BTW), or both. The complex interaction between initial bolt-up, the initial bolt-up method (hammer wrench, torque wrench, hydraulic tensioners, etc) the gasket (especially if you use compound gaskets like spiral-wound gaskets), operating conditions (high temperature, gasket creep, bolt creep, bolt thread embedment, vibration, etc), operating fluid properties all make for a very difficult "calculation" for those who lack experience and expertise. You may spend a lot of time getting a complicated calculation sheet, but you'll end up with a very good looking wrong answer.
RE: ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
The verification I have to carry out still belongs to a design step, I'm not dealing with in-service equipment. I'm trying to make the calculation more automated, so I verified the possibility to use those formulas. Since the graphs I obtained for factors F and V don't correspond with tables 2-7.3, 2-7.6 I was wondering if anybody had the same problem. Anyway I really appreciated the suggestion "..but you'll end up with a very good looking wrong answer." , bacouse in the end this is the risk!
RE: ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
RE: ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"
I rememeber something about a problem with these constant, they should have been corrected in one of the subsequent Addenda. If possible, procure 2007 edition and compare the constants.
Regarding the methodology itself, I concur with TGS4; moreover, if you would like to accurately check flange behaviour, I suggest you to rely on EN 13445 Appendix G, wich details a completely different approach to flange desing.
In case of metal-to-metal flange, examine EN 1591-3.
Hope this helps..
Regards
RE: ASME VIII - Div. 1 App. 2, 2004 ed. "Flange factors in formula form"