Pipe Flange 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 B16.20 - Ring Joint Gaskets and Grooves for Steel Pipe Flanges
• ASME B16.21 - Nonmetallic Flat Gaskets for Pipe Flanges
• ASME B16.24 - Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500, and 2500
• ASME B16.34 - Large Diameter Steel Flanges (NPS 26 through NPS 60)
• 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 - Specification for Carbon Steel Forgings for Piping Applications
• ASTM A182 - Specification for Forged or Rolled Alloy Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service
• ASTM A193 - Specification for Alloy Steel and Stainless Steel Bolting Materials for High Temperature Service
• ASTM A194 - Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service
• ASTM A694 - Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service
• ASTM A707 - Specification for Flanges, Forged, Carbon and Allow Steel for Low Temperature Service

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-6 - Standard Finishes for Contact Faces Pipe Flanges and Connecting End Flanges of Valves and Fittings
• 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-53 - Quality Standards for Steel Castings and Forgings for Valves, Flanges and Fittings and Other Piping Components - Magnetic Particle
• MSS SP-54 - Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components - Radiographic
• MSS SP-55 - Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components - Visual
• MSS SP-75 - High Test Wrought Butt Welding Fittings
• 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).

Blind Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
• ASME B16.47 - Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard
  • Series A / MSS SP-44
    • For general use
    • Bolt circle diameter is larger than Series B
    • NOT interchangeable
  • Series B / API Std 605 (cancelled)
    • For compact use
    • Bolt circle diameter is smaller than Series A
    • NOT interchangeable

Ductile Iron Flange Standards

• ASME Standards
  • ASME B16.1 - Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
• AWWA Standards
  • AWWA C110 - Standard for Ductile-Iron and Gray-Iron Fittings
  • AWWA C115 - Standard for Flanged Ductile Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges

Expander Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Lap Joint Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Orifice Flange Standards

ASME Standards

• ASME B16.36 - Orifice Flanges
  • 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

Slip-On Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Socket Weld Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Standard Connection Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Studding Outlet Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Threaded Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

Weld Neck Flange Standards

ASME Standards

• ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
• ASME B16.36 - Orifice Flanges
• ASME B16.47 - Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard
  • Series A / MSS SP-44
    • For general use
    • Bolt circle diameter is larger than Series B
    • NOT interchangeable
  • Series B / API Std 605 (cancelled)
    • For compact use
    • Bolt circle diameter is smaller than Series A
    • NOT interchangeable