Flange facing roughness 2

[FIF99]

Hi,

Within ASME B16.5 a standard RF flange facing roughness is specified between 125 and 250 AARH (smooth finish). Is this roughness suitable for all gasket types?
For rubber type of flange gaskets I thought it is recommended to specify stock finish (between 250 and 500 AARH).

Anybody who would like to share some experience?

Thanks in advance!

Regards,
FKE

 

[codeeng]

As a general rule smooth finish is for metal gaskets, stock finish for sheet gaskets.

 

[EEG]

Per the latest edition of ASME B16.5, there longer is a stock and smooth finish. The Standard finish for all flanges built to B16.5 is 125 to 250.

 

[Cockroach]

250 Ra, that's why a gasket seals! Cruise the Flexatallic wetsite, 125 Ra is a bit fine.

I agree with earlier postings.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[FIF99]

Hi,

All, thanks for your input.

Yes, ASME B16.5 is specifying smooth finish as standard, but gasket suppliers recommend stock finish (6.3 mu - 12.5 mu or 250AARH - 500AARH) for Rubber type gaskets due to better sealing.

Since most vendors are quoting according B16.5, i.e. smooth finish, we regularly have to ask the manufacturers to pay attention in order to apply stock finish.

Nevertheless it seams that nowadays smooth finish will result in an acceptable level of sealing quality for the whole range of RF gasket types.

Anyway, thank you all again for your input.

Regards,
FKE