ASME B16.36 Orifice Flange Dimensions
This chart gives ASME B16.36 weld neck orifice flange dimensions in millimetres for Class 300 and Class 600, NPS 1" to 24". Orifice flanges are supplied in pairs to hold an orifice plate for flow measurement; each flange carries pressure taps and a jack screw.
Outside diameter, raised face and drilling are the same as ASME B16.5 flanges of the same class, so orifice flanges mate with standard flanges and pipe. The minimum thickness is 36.6 mm (1.44") to leave room for the radial taps. Teshi Group manufactures orifice flange sets with jack screws, plugs and stud bolts.
Key to dimensions
- O
- Outside diameter of flange
- T
- Minimum flange thickness, excluding the raised face
- R
- Diameter of raised face
- X
- Hub diameter at base
- Y
- Length through hub
- W
- Bolt circle diameter
- Holes
- Number of bolt holes
- Bolt
- Nominal stud bolt diameter in inches
- Stud
- Stud bolt length for a raised-face orifice flange pair
ASME B16.36 Orifice Flange Dimensions — tables
Class 300 orifice flange dimensions (mm)
| NPSin | OOutside dia | TMin thickness | RRaised face dia | XHub dia | YLength thru hub | WBolt circle | HolesNo. | Hole diamm | Boltin | StudLength, mm |
|---|---|---|---|---|---|---|---|---|---|---|
| 1" | 125 | 36.6 | 50.8 | 54 | 81 | 88.9 | 4 | 19.1 | ⅝" | 125 |
| 1½" | 155 | 36.6 | 73.0 | 70 | 84 | 114.3 | 4 | 22.2 | ¾" | 135 |
| 2" | 165 | 36.6 | 92.1 | 84 | 84 | 127.0 | 8 | 19.1 | ⅝" | 125 |
| 2½" | 190 | 36.6 | 104.8 | 100 | 87 | 149.2 | 8 | 22.2 | ¾" | 135 |
| 3" | 210 | 36.6 | 127.0 | 117 | 87 | 168.3 | 8 | 22.2 | ¾" | 135 |
| 4" | 255 | 36.6 | 157.2 | 146 | 90 | 200.0 | 8 | 22.2 | ¾" | 135 |
| 6" | 320 | 36.6 | 215.9 | 206 | 98 | 269.9 | 12 | 22.2 | ¾" | 135 |
| 8" | 380 | 39.7 | 269.9 | 260 | 110 | 330.2 | 12 | 25.4 | ⅞" | 145 |
| 10" | 445 | 46.1 | 323.8 | 321 | 116 | 387.4 | 16 | 28.6 | 1" | 165 |
| 12" | 520 | 49.3 | 381.0 | 375 | 129 | 450.8 | 16 | 31.8 | 1⅛" | 180 |
| 14" | 585 | 52.4 | 412.8 | 425 | 141 | 514.4 | 20 | 31.8 | 1⅛" | 185 |
| 16" | 650 | 55.6 | 469.9 | 483 | 144 | 571.5 | 20 | 34.9 | 1¼" | 195 |
| 18" | 710 | 58.8 | 533.4 | 533 | 157 | 628.6 | 24 | 34.9 | 1¼" | 205 |
| 20" | 775 | 62.0 | 584.2 | 587 | 160 | 685.8 | 24 | 34.9 | 1¼" | 215 |
| 24" | 915 | 68.3 | 692.2 | 702 | 167 | 812.8 | 24 | 41.3 | 1½" | 240 |
Class 600 orifice flange dimensions (mm)
| NPSin | OOutside dia | TMin thickness | RRaised face dia | XHub dia | YLength thru hub | WBolt circle | HolesNo. | Hole diamm | Boltin | StudLength, mm |
|---|---|---|---|---|---|---|---|---|---|---|
| 1" | 125 | 36.6 | 50.8 | 54 | 81 | 88.9 | 4 | 19.1 | ⅝" | 125 |
| 1½" | 155 | 36.6 | 73.0 | 70 | 84 | 114.3 | 4 | 22.2 | ¾" | 135 |
| 2" | 165 | 36.6 | 92.1 | 84 | 84 | 127.0 | 8 | 19.1 | ⅝" | 125 |
| 2½" | 190 | 36.6 | 104.8 | 100 | 87 | 149.2 | 8 | 22.2 | ¾" | 135 |
| 3" | 210 | 36.6 | 127.0 | 117 | 87 | 168.3 | 8 | 22.2 | ¾" | 135 |
| 4" | 275 | 38.1 | 157.2 | 152 | 102 | 215.9 | 8 | 25.4 | ⅞" | 150 |
| 6" | 355 | 47.7 | 215.9 | 222 | 117 | 292.1 | 12 | 28.6 | 1" | 180 |
| 8" | 420 | 55.6 | 269.9 | 273 | 133 | 349.2 | 12 | 31.8 | 1⅛" | 195 |
| 10" | 510 | 63.5 | 323.8 | 343 | 152 | 431.8 | 16 | 34.9 | 1¼" | 220 |
| 12" | 560 | 66.7 | 381.0 | 400 | 156 | 489.0 | 20 | 34.9 | 1¼" | 230 |
| 14" | 605 | 69.9 | 412.8 | 432 | 165 | 527.0 | 20 | 38.1 | 1⅜" | 240 |
| 16" | 685 | 76.2 | 469.9 | 495 | 178 | 603.2 | 20 | 41.3 | 1½" | 260 |
| 18" | 745 | 82.6 | 533.4 | 546 | 184 | 654.0 | 20 | 44.5 | 1⅝" | 280 |
| 20" | 815 | 88.9 | 584.2 | 610 | 190 | 723.9 | 24 | 44.5 | 1⅝" | 300 |
| 24" | 940 | 101.6 | 692.2 | 718 | 203 | 838.2 | 24 | 50.8 | 1⅞" | 335 |
Notes
- Dimensions are in millimetres unless stated otherwise. Bolt holes and bolt diameters follow ASME B16.5 (inch); the mm values are conversions.
- The bore is machined to the pipe inside diameter specified by the purchaser.
- Each flange has two pressure taps, usually ½" NPT, on opposite sides; other tap sizes and orientations are supplied on request.
- One jack screw per flange, set 180° apart, is used to separate the flanges to change the orifice plate.
- Raised face height is 2 mm for Class 300; for Class 600 it is 2 mm at NPS 1–3 and 7 mm at NPS 4–24.
- Stud lengths include an allowance of about 6 mm for the orifice plate and gaskets (NPS 1–12).
- Class 600 orifice flanges from NPS 1 to 3 have the same dimensions as Class 300.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
Equivalent and related standards to ASME B16.36 Orifice Flange Dimensions
All equivalents| Region | Standard | Relationship |
|---|---|---|
| China | HG/T 20615 / SH/T 3406 | Orifice flanges to ASME B16.36 dimensions |
| USA | ASME MFC-3M | Orifice metering practice using B16.36 flanges |
Teshi Group manufactures flanges and fittings to all of these standards on request, including Chinese GB / HG / SH and European EN dimensions for export projects. Always confirm bolting, facing and thickness when substituting one standard for another.
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ASME B16.36 Orifice Flange Dimensions — size by size
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FAQ
ASME B16.36 Orifice Flange dimensions: common questions
What is the thickness of a Class 300 orifice flange?
ASME B16.36 sets a minimum thickness of 36.6 mm (1.44") for Class 300 orifice flanges up to NPS 6, which is thicker than a standard Class 300 flange so the pressure taps can be drilled radially. From NPS 8 the standard ASME B16.5 thickness applies.
What size are the pressure taps on an orifice flange?
Two taps per flange, normally ½" NPT, drilled on opposite sides. Other sizes, such as ¾" NPT or socket weld taps, are made on request.
Can orifice flanges be supplied as a complete set?
Yes. Teshi Group supplies orifice flanges in matched pairs with jack screws, tap plugs, stud bolts and nuts, and can include the gaskets.
Related products, data sheets and standards
Weld Neck Flange
OEM manufacturer
View online · PDFASME B16.5ASME B16.5 Class 300 flange dimensions
Class 300 flange outside diameter, thickness, hub and drilling dimensions, NPS ½–24, in mm.
View online · PDFASME B16.5ASME B16.5 Class 600 flange dimensions
Class 600 flange dimensions and bolting, NPS ½–24, in mm.
View online · PDFASME B1.20.1NPT thread dimensions (ASME B1.20.1)
Threads per inch, pitch, engagement lengths and pitch diameters of NPT taper pipe threads.
View online · PDFASME B16.5Stud bolt chart for ASME B16.5 flanges
Number, diameter and length of stud bolts for raised-face and ring-joint flanges, Class 150–2500.
View online · PDF
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