... : Bolted, cover, swing type disc, threaded, or welded seat ring 2) Standard compliance: A) Basic design: BS 1868 B) Face to ... ) End to end dimension: ANSI B16.10 D) Flanged ends: I) 2 - 24" to ANSI B16.5 II) 24" to MSS SP ... . W. Ends to ANSI B16.25 E) Shell wall thickness: I) 2 - 24" to API 600 II) > 24" to manufacturer's standard ...