Mating surfaces of flanges 1

[ww2]

Can someone advice me where I can find the norm (what norm?) for finish, flatness and waviness specifications, for mating surfaces of flanges.
Many thanks
koekoek

 

[monk75]

Try ASME/ANSI B16.5 Table 3 titled Permissable Imperfections in Flange Facing Finish for B16.5 flanges.

MSS SP-6 for B16.1 for cast iron flanges

 

[ww2]

Thank you monk75, this helps me with the finish of the mating surfaces. The question on flatness and waviness remains open, anyone else, please?

 

[tothepoint]

I went looking for the very same information today and could not find it. B16.5 and Taylor Forge- nothing about the surface flatness was mentioned. Anyone else??

 

[bmoorthy]

Flatness of Girth flanges in a heat exchanger are delt with in API standard for refinery Heat exchangers. I am not sure whether it is API 660 or API 661. One of it is air fin exchanger the other is the exchanger for refinery service. This is tabulated against the diameter of the girth flange. 0.3mm for flange of dia 2500mm.

For Surface finish also refer B46.

Also you may Refer to TEMA this gives allowable defects in Raised face of Gasket face. Scratch marks, scoring etc are given here. you may use these as Norms.

 

[ww2]

Thank you bmoortly, to my feeling this is a step in the wright direction. I'll see if a can get hold of API 660 and 661.
koekoek

 

[bvi]

It is API 660, which is more stringent than the TEMA flatness requirements. The same information is provided in ASME PCC-1, Guidelines for Pressure Boundary Bolted Flange Joint Assembly, so you may wish to get that document, which deals specifically with bolted joints, rather than the heat exchanger standard.

 

[ww2]

Thank you cb4 I believe we are getting somewhere
koekoek

 

[bmoorthy]

CB4

Great stuff, does it (ASME PCC1) give acceptable defect size in RTJ type flanges?

 

[bvi]

I had remembered wrong. ASME PCC-1 repeats the flange flatness requirements of PIP VESV1002, Vessel/S&T Heat Exchanger Fabrication Specification.

It doesn't have any flatness requirements specific to ring joint flanges. Note B16.5 has a surface finish requirement for ring joint flange grooves.