Corelation between gasket and gasket Seating Surface Finish

[bmoorthy]

1) Where can one find the types of gaskets (Various types of gaskets and not the supplier's brouchers) and the recommeded/Specified gasket Sating surface (In ASME or ASTM/ANSI/API/MSS SP or any such Code/Standard) for the respective gaskets (For standard flange.

ASME Sec VIII Div 1 appendix table lists the various gaskets types but the gasket finish (in the seating surface)for each type of gasket is elusive.

2)Also is 125Ra to 250Ra considered smooth or Serrated?

ANSI 16.5 and B 46.1 deals with the finish but to corelate the finish of the gasket seating finish with the type of gasket chosen is not clear.

 

[SnTMan]

bmoorthy, for flange surface finish vs gasket type I think you are going to have to rely on the gasket suppliers. They know their products.

For Sec VIII, Div. 1, Apx 2 design, all these parameters have only to do with adequate strength of the flange and bolting, you can meet all these requirements and still have a flange that leaks like a sieve.

Leak tightness requires another set of considerations.

I am not sure about smooth vs serrated, but I think you will find that a 125-250 spiral or "phonograph" finish will be suitable for most common gaskets, except perhaps where extreme leak tightness is required.

Regards,

Mike

 

[jehan17718]

bmoorthy,

You may also want to check with the project P&ID and corresponding PMS (piping material specifications) which specify the flange finish (in addition to the Gasket MOC, etc).

If there exixts a basis then this should be the input.

My comment is based from a Pressure vessel designer's point of view only.

-Jehan