1. Class 300 flanges except Lap Joint will be furnished with 0.06 (1.6mm) raised face, which is included in ‘Thickness’ (C) and ‘Length through Hub’ (Y1), (Y3).
2. For Slip-on, Threaded, Socket Welding and Lap Joint Flanges, the hubs can be shaped either vertical from base to top or tapered within the limits of 7 degrees.
3. Blind Flanges may be made with the same hub as that used for Slip-on Flanges or without hub.
4. The gasket surface and backside (bearing surface for bolting) are made parallel within 1 degree. To accomplish parallelism, spot facing is carried out according to MSS SP-9, without reducing thickness (C).
5. Depth of Socket (D) is covered by ANSI B 16.5 only in sizes through 3 inch, over 3 inch is at the manufacturer’s option.