Join between RF and FF flanges
Join between RF and FF flanges
(OP)
How can I joint RF and FF Flanges? Do I will need an special gasket?
Orangel Roca
Orangel Roca
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Join between RF and FF flanges
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RE: Join between RF and FF flanges
http://www.gouldspumps.com/pom_0007.html
RE: Join between RF and FF flanges
Don't!
Only join mated flanges. Some -if not most- flat flanges are inherently made of Cast Iron. If you try to match a flat cast iron flange against a steel raised face flange, the steel variety will win the contest. The flat flange will break up when the bolts are torqued.
RE: Join between RF and FF flanges
Paul Ostand
www.ostand.com
RE: Join between RF and FF flanges
RE: Join between RF and FF flanges
For such reasons, I know that some manufacturers in the water and wastewater industries (e.g. ACIPCO) went with all-ductile iron companion flanges decades ago (even though others insisted on selling and keeping gray cast iron companion flanges in some standards).
I would offer up that in general ductile iron and steel flanges will be much harder to break than say gray cast iron items, when subjected to adverse loading by bolts or otherwise. I also remember there was some additional guidance offered up in some manufacturers literature and at least ANSI/AWWA standards I think with regard to a sort of unsupported bolting (see under "Bolts and Gaskets" heading at http://www.acipco.com/adip/pipe/flanged/dda.cfm, "Also, per the Appendix of AWWA C110 and C115, high-strength bolts should not be used when a gray iron flange is involved in the connection." I guess the rationale (that could conceivably also be of interest here or other situations) is that lower strength bolts might at least make a not-too-delicate contractor etc. to at least work a little harder to break the gray cast iron flanges!
RE: Join between RF and FF flanges
RE: Join between RF and FF flanges
RE: Join between RF and FF flanges
The original post asked about mating a FF to a RF. Not specifically #125 or #250 cast iron to B16.5 steel RF flanges.
If both RF and FF flanges were #150 ASTM A105 flanges what specific section of an ASME piping code prohibits mating these together?
I certainly do not defend mating FF to RF as a recommended practice; however, sometimes life is not always convenient. What is important is to understand the consequence of the decision to mate FF to RF and decide if the benefit outweighs the risk.
RE: Join between RF and FF flanges
RE: Join between RF and FF flanges
make a 1/16" thk steel ring plate equal to the height of the raised face and to cover the area outside the bolt hole on the raised flange. So, it makes like a flat face flange. It is working fine on the water service at 150psig.
RE: Join between RF and FF flanges
I suspect this has probably "worked" for some folks in some applications based on these posts; however, it could be argued that this concept might in essence defeat any sealing (or bolt torquing?) intent of the original product or standard raised face designer. Also, I think that (at least for some products and per some standards) it is possible the height of the raised face might not necessarily be a specifically (or precisely) controlled dimension, perhaps resulting in unintended joining mismatch or concerns. Therefore, it may be adviseable to carefully consider these points, including the dimensions of the actual raised face and ring etc. to be joined, if an outer annular ring or adaptor s to be placed around same.
RE: Join between RF and FF flanges
RE: Join between RF and FF flanges