Orifice Flange Unions

Quality Beyond Compare

EExceptional performance and superior durability are the hallmarks of Daniel Orifice Flange Unions. Available in line sizes 2-inch to 8-inch and ANSI 600 to 2500 with carbon steel or stainless steel assembly. Every Daniel OFU is expertly manufactured to meet or exceed AGA 3/API 14.3 standards.

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Mechanical Ratings Standard: 2-in to 8-in, ANSI 600-2500

Consult factory for other options

Flange Face And End Connections Standard: Raised face weldnek and ring-joint weldnek
Assembly Carbon Steel: furnished complete with studs (ASTM A-193 GR B7), nuts (ASTM A-194 GR 2H), (2) 0.0625-in non-asbestos gaskets and (2) jackscrews

Stainless Steel: furnished complete with zinc plated studs (ASTM A-193 GR B7), nuts (ASTM A-194 GR 2H), (2) 0.0625-in non-asbestos gaskets and (2) jackscrews

Differential Pressure Taps Location and number of tap holes

  • Standard: 2 tap holes with orientation on top and bottom 180 deg apart, in accordance with API 14.3 (AGA3) or ISO 5167
  • Consult factory for other tap location and number of tap options

Process connection

  • Standard: .50-in NPT standard
  • Consult factory for other options

Types of tap connections

  • Standard: Threaded
  • Optional: Socket weld
  • Consult factory for other options

Line bore tolerances

  • Standard size: Sch 40 and 80
  • Consult factory for other options
Temperature Range Standard: -20°F to +250°F (-29°C to +121°C)

Standard (low temperature): -100°F to +250°F (-73°C to +121°C)

Consult factory for other options

Material Specifications Standard: A105 Carbon Steel and A350 LF-2 (low temperature applications)

Consult factory for other options

Flow Measurement Code API 14.3


Design Code ASME B16.36
Gaskets Standard gaskets for RF flanges are 0.625-in thick. (0.125-in thick gaskets are available as an option.)

  • Grafoil gasket
  • Spiral wound gasket without inner ring
  • Garlock gylon
  • Spiral wound gasket with inner ring

RTJ Flanges use Daniel model 560 or 590 style plate holders. The plate holder is designed with an equivalent ring gasket to match the R-number based on size and pressure class.

  • Bore Tolerances are well within the latest recommendations of API-14.3.
  • Pressure Tap Hole Location is closely controlled. Tap hole centers are 0.938-in from bearing faces of raised face flanges, placing their centerline 1-in from the face of the orifice plate when 0.063-in gasket thickness is included.
    • 1. For 3-in and smaller flanges, tap location tolerance is ± 0.016-in.
    • 2. For 4-in and larger flanges, tap location tolerance is ± 0.031-in.
  • Pressure Tap Holes – Tap hole edges on the flange bore surface are carefully inspected to be free from burrs. All roughness is eliminated. Sizes are shown in the following tables.
  • Flange Tap Connections – Standard connections are .50-in NPT. Other sizes and types are available on request.
  • Gaskets – Two 0.063-in thick(1) precision die-cut gaskets are furnished with all raised face orifice flanges. Non-asbestos gaskets are standard.
  • Dowel pins: Alignment dowel pins of the knock-out type are furnished as standard on all 2-in to 8-in raised face orifice flanges. These dowel pins assure correct alignment of the flange bores as well as centering the orifice plate bore to the flange bores within the tolerances of API-14.3.
Line Size DN50 to DN200 (2-in to 8-in)
Fluid Type Liquid
Operating Temperature Range -29º C to +66º C (-20º F to +150º F)
Operating Pressure Range ANSI 150 to 300
Materials: Valve Body Carbon Steel, ASTM A352 GR LCC
Materials: Valve Cylinder DN50 to DN 200 (2-in to 4-in): Stainless Steel, ANSI 150 to 600; DN250 to DN 300 (6-in to 8-in) Carbon Steel, Nickel Coated, ANSI 150 to 600
Materials: Valve Piston Standard: Stainless Steel
Materials: Seat Ring DN50 to DN200 (2-in to 6-in) Stainless Steel; DN300 (8-in) Carbon Steel, Nickel Coated
Materials: O-Rings Standard: Viton; Optional: Neoprene, EPR, Kalrez / Teflon AP (Aggressive Products)