Pipe flange check
Pipe flange check
(OP)
The ASME Sec VIII Division 1 Mandatory Appendix 2 'Rules for bolted flange connections with ring type joints' does not consider additional tension or bending moment but only pressure, internal or external. I observed that people used pressure equivalent method alsong with this to check flanges (thread378-18541: Flange Bending Moments http://www.eng-tips.com/viewthread.cfm?qid=18541).
We have ASME Sec VIII Division 2 Para 4.16 'Design Rules for Flanged joints' and here both the external loading, additional tension as well as bending moment are considered. The question is why then we have to go for Div1 method along with peq instead of Div2 method all the time? Also, for API 6B and 6BX flanges, can we use ASME Div 2 method in addition to API 6AF, 6AF1 and 6AF2 methods?
We have ASME Sec VIII Division 2 Para 4.16 'Design Rules for Flanged joints' and here both the external loading, additional tension as well as bending moment are considered. The question is why then we have to go for Div1 method along with peq instead of Div2 method all the time? Also, for API 6B and 6BX flanges, can we use ASME Div 2 method in addition to API 6AF, 6AF1 and 6AF2 methods?





RE: Pipe flange check
Since both are approved Codes, you should be able to use either, thus use Div 2 to consider external loads.
Why would you need to calculate API flanges when allowable loads are all quoted in 6AF2 ? The values in 6AF2 are all results from extensive 3D finite element analyses, which is far superior to Div 1 + Peq and Div 2.
RE: Pipe flange check
https://www.scribd.com/doc/206851934/Eq-Pressure
Internally we use a modified Div 1 method for flange calculations, in which the rules of the document provided in the link have been used.
Apart from the equivalent pressure method, there's an enhanced/updated method to this which has been published by BFJ-gutu Warren Brown;
http://proceedings.asmedigitalcollection.asme.org/...
RE: Pipe flange check
By the way, how should I interpret the word "Integral" in the title of API 6AF2 "Technical Report on capabilities of API integral flanges under combination of Loading - Phase II"? IN ASME BPVC Sec VII Div 1 and 2 in comparison to API Spec 6A define the type "integral" differently. Or is it only me?