Flange end-Raised Face per ASME B16.5, standard 3.2/6.3 Ra flange facing finish per ASME B46.1, ASME16.34, API594. The flange facing is required to be serrated raised face. I am asking if the above spec clarifies the face to be serrated. Sounds like a ball valve smooth finish to me. Serrated flanges have roughness in the 125-250 range. 3.2-6.3 is slick as nasal exudate on a portal fastener. BUT more significantly your spec should say "Serrated Gasket Surface". AND there are phonograpic (spiral)serrations OR (expensive) Concentric grooves. Smooth surfaces are used for Flexitallic-type spiral-wound gaskets. Serrated flanges are used with rubber or composition gaskets. The spiral of a Flexitallic usually does not match the spiral of the serration, so you get the hard spots of the gasket perched up on the high spots of the flange serrations with likely leakage.

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