Tongue and Groove Flanges 1

[Bobfromoh]

Our customer is builing a 6' diameter vessel, 600 psi @ 1000F. Initially, the vessel was specified with raised face
body flanges. After futher review the cusomer is interested in using tongue & groove flanges.

Is ther any guidlines for when a raised face joint won't work and a T & G flange is neded.

 

[unclesyd]

We normally go with RTJ flanges when we are concerned there could be problems with a RF flange.
We stay away from T&G flanges especially if they will there be frequent making and breaking due to potential damage to the tongue. Also some T&G gaskets are quite fragile.

We don't have any trouble with RF flanges as we used the appropriate spiral wound gaskets and kinda insist on proper make up using new gaskets each time.

What was the clients specific concerns?

 

[MJCronin]

Ohio Bob...

In response to your question, no... there are no hard and fast rules about flange face selection and yes... there is overlap in acceptable pressure ranges

I would suggest that you stay with the RF flanges mostly for the reasons stated above. In my opinion, only when you have exceeded the design condition of ASME Class 900 for the flanges should you consider someting other than RF.

-MJC

 

[gr2vessels]

Hi Bob,
The raised face flanging advantages are coming from the principle of the gasket being located by the flange bolting, allowing easy handling and good sealing performance. It also lends itself for standardization, thus allowing costs reduction, safe operating limits and conditions...However, larger sized equipment like heat exchangers or horizontal vessels with girth flanges, requiring custom design sealing system, particularly in corrosive service, can make use of the tongue and groove arrangement to facilitate the location of a relative narrow gasket in a groove, where the depth of the groove may also be considered as part of the pressure retaining thickness of the flange. It could be significant saving. However, there are also many reasons to not use tongue and groove sealing arrangement in some services, where other arrangements are more suitable.
cheers,
gr2vessels