General Flange Standards

Flange Standards

• Flange - ASME B16.36, Orifice Flange (1/2"-24")
  • Slip-on Flange: Class 300, Class 400, Class 600, Class 900, Class 1500
  • Threaded Flange: Class 300, Class 400, Class 600, Class 900, Class 1500
  • Weld Neck Flange: Class 300, Class 400, Class 600, Class 900, Class 1500, Class 2500

• Flange - Industry Standard Flange (also called Large Diameter Flange) (26"-larger)
  • Industry Standard Flanges have no national standard code or are they covered by any governing body.
    • Blind Flange: Class 75, Class 125, Class 175, Class 250, Class 350
    • Weld Neck Flange: Class 75, Class 125LW, Class 125, Class 175, Class 250, Class 350
    • Slip-on Flange: Class 75, Class 125LW, Class 125, Class 175, Class 250, Class 350

• Flange - AWWA Standard Flange
  • AWWA C207
    • Steel Ring Flange: Class B, Class D, Class E, Class F
    • Steel Hub Flange: Class D, Class E
    • Blind Flange: Class B, Class D, Class E, Class F
  • AWWA C207
    • Steel Ring Flange: Class B, Class D, Class E, Class F
    • Steel Hub Flange: Class D, Class E
    • Blind Flange: Class B, Class D, Class E, Class F

Standards

ASME Standards

• ASME B16.1 - Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
• ASME B16.24 - Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500, and 2500
• ASME B16.36 - Orifice Flanges
• ASME B16.42 - Ductile Iron Pipe Flanges and Flanged Fittings: Classes 150 and 300
• ASME B16.47 - Large Diameter Steel Flanges, NPS 26 Through NPS 60

ASTM Standards

• ASTM A105 / A105M - Specification for Carbon Steel Forgings for Piping Applications

AWWA Standards

• AWWA C115 - Standard for Flanged Ductile Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges

ISO Standards

• ISO 5251 - Stainless steel butt-welding fittings

MSS Standards

• MSS SP-9 - Spot Facing for Bronze, Iron and Steel Flanges
• MSS SP-25 - Standard Marking Systems for Valves, Fittings, Flanges, and Unions
• MSS SP-44 - Steel Pipeline Flanges
• MSS SP-106 - Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300

• ASME B16.5 and ASME B16.47 cover pipe flanges up to NPS 60 (B16.5 from 1/2" to 24" and B16.47 from 26" to 60"). ANSI B16.47 covers two series of flanges, Series A is equal to MSS SP-44-44, and Series B is equal to API 605 (API 605 has been canclled).