Class 300 flange dimensions, ASME B16.5
Every dimension for 1/2" to 24" Class 300 flanges, the workhorse class for process plants, steam and hydrocarbon lines. Weld neck, slip-on, socket weld, threaded, lap joint and blind, with a drawing made to scale.
Class 300 flange finder with cross-section
Choose the size and type. Every dimension is marked on a drawing made to scale.
Flange dimension finder
Every ASME B16.5 dimension for weld neck, slip-on, socket weld, threaded, lap joint and blind flanges, ½ to 24 inch, Class 150 to 2500, and ASME B16.47 Series A and B weld neck and blind flanges, 26 to 60 inch. The section redraws to scale as you change type, size and class.
Dimensions per ASME B16.5 (½ to 24 inch) and ASME B16.47 (26 to 60 inch). The raised face is not included in thickness or hub length. Matching stud bolts come from Teshi Fasteners as a set.
Class 300 dimensions in mm
| Size | O | T | R | X | A | W (PCD) | Bolts | Y weld neck | Y slip-on / SW / thd | Y lap joint | B slip-on | B lap joint | C socket | D socket | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2" (15 NB) | 95.2 | 12.7 | 35.1 | 38.1 | 21.3 | 66.5 | 4 × 1/2" | 50.8 | 20.6 | 22.4 | 22.4 | 22.9 | 23.6 | 9.7 | Quote |
| 3/4" (20 NB) | 117.3 | 14.2 | 42.9 | 47.8 | 26.7 | 82.5 | 4 × 5/8" | 55.6 | 23.9 | 25.4 | 27.7 | 28.2 | 29.0 | 11.2 | Quote |
| 1" (25 NB) | 124.0 | 15.7 | 50.8 | 53.8 | 33.5 | 88.9 | 4 × 5/8" | 60.5 | 25.4 | 26.9 | 34.5 | 35.1 | 35.8 | 12.7 | Quote |
| 1-1/4" (32 NB) | 133.3 | 17.5 | 63.5 | 63.5 | 42.2 | 98.6 | 4 × 5/8" | 63.5 | 25.4 | 26.9 | 43.2 | 43.7 | 44.4 | 14.2 | Quote |
| 1-1/2" (40 NB) | 155.4 | 19.0 | 73.2 | 69.8 | 48.3 | 114.3 | 4 × 3/4" | 66.8 | 28.7 | 30.2 | 49.5 | 50.0 | 50.3 | 15.7 | Quote |
| 2" (50 NB) | 165.1 | 20.6 | 91.9 | 84.1 | 60.5 | 127.0 | 8 × 5/8" | 68.3 | 31.8 | 33.3 | 62.0 | 62.5 | 63.5 | 17.5 | Quote |
| 2-1/2" (65 NB) | 190.5 | 23.9 | 104.6 | 100.1 | 73.2 | 149.4 | 8 × 3/4" | 74.7 | 36.6 | 38.1 | 74.7 | 75.4 | 76.2 | 19.0 | Quote |
| 3" (80 NB) | 209.5 | 26.9 | 127.0 | 117.3 | 88.9 | 168.1 | 8 × 3/4" | 77.7 | 41.4 | 42.9 | 90.7 | 91.4 | 92.2 | 20.6 | Quote |
| 3-1/2" (90 NB) | 228.6 | 28.4 | 139.7 | 133.3 | 101.6 | 184.1 | 8 × 3/4" | 79.5 | 42.9 | 44.4 | 103.4 | 104.1 | – | – | Quote |
| 4" (100 NB) | 254.0 | 30.2 | 157.2 | 146.0 | 114.3 | 200.2 | 8 × 3/4" | 84.3 | 46.2 | 47.8 | 116.1 | 116.8 | – | – | Quote |
| 5" (125 NB) | 279.4 | 33.3 | 185.7 | 177.8 | 141.2 | 234.9 | 8 × 3/4" | 97.0 | 49.3 | 50.8 | 143.8 | 144.5 | – | – | Quote |
| 6" (150 NB) | 317.5 | 35.1 | 215.9 | 206.2 | 168.4 | 269.7 | 12 × 3/4" | 97.0 | 50.8 | 52.3 | 170.7 | 171.4 | – | – | Quote |
| 8" (200 NB) | 381.0 | 39.6 | 269.7 | 260.3 | 219.2 | 330.2 | 12 × 7/8" | 109.7 | 60.5 | 62.0 | 221.5 | 222.2 | – | – | Quote |
| 10" (250 NB) | 444.5 | 46.0 | 323.8 | 320.5 | 273.1 | 387.3 | 16 × 1" | 115.8 | 65.0 | 95.2 | 276.4 | 277.4 | – | – | Quote |
| 12" (300 NB) | 520.7 | 49.3 | 381.0 | 374.6 | 323.8 | 450.8 | 16 × 1-1/8" | 128.5 | 71.6 | 101.6 | 327.2 | 328.2 | – | – | Quote |
| 14" (350 NB) | 584.2 | 52.3 | 412.8 | 425.4 | 355.6 | 514.4 | 20 × 1-1/8" | 141.2 | 74.7 | 111.3 | 359.2 | 360.2 | – | – | Quote |
| 16" (400 NB) | 647.7 | 55.6 | 469.9 | 482.6 | 406.4 | 571.5 | 20 × 1-1/4" | 144.5 | 81.0 | 120.6 | 410.5 | 411.2 | – | – | Quote |
| 18" (450 NB) | 711.2 | 58.7 | 533.4 | 533.4 | 457.2 | 628.6 | 24 × 1-1/4" | 157.2 | 87.4 | 130.0 | 461.8 | 462.3 | – | – | Quote |
| 20" (500 NB) | 774.7 | 62.0 | 584.2 | 587.2 | 508.0 | 685.8 | 24 × 1-1/4" | 160.5 | 93.7 | 139.7 | 513.1 | 514.4 | – | – | Quote |
| 24" (600 NB) | 914.4 | 68.3 | 692.1 | 701.5 | 609.6 | 812.8 | 24 × 1-1/2" | 166.6 | 104.9 | 152.4 | 615.9 | 615.9 | – | – | Quote |
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Class 300 dimensions in inches
| Size | O | T | R | X | A | W (PCD) | Bolts | Y weld neck | Y slip-on / SW / thd | Y lap joint | B slip-on | B lap joint | C socket | D socket | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2" (15 NB) | 3.75 | 0.50 | 1.38 | 1.50 | 0.84 | 2.62 | 4 × 1/2" | 2.00 | 0.81 | 0.88 | 0.88 | 0.90 | 0.93 | 0.38 | Quote |
| 3/4" (20 NB) | 4.62 | 0.56 | 1.69 | 1.88 | 1.05 | 3.25 | 4 × 5/8" | 2.19 | 0.94 | 1.00 | 1.09 | 1.11 | 1.14 | 0.44 | Quote |
| 1" (25 NB) | 4.88 | 0.62 | 2.00 | 2.12 | 1.32 | 3.50 | 4 × 5/8" | 2.38 | 1.00 | 1.06 | 1.36 | 1.38 | 1.41 | 0.50 | Quote |
| 1-1/4" (32 NB) | 5.25 | 0.69 | 2.50 | 2.50 | 1.66 | 3.88 | 4 × 5/8" | 2.50 | 1.00 | 1.06 | 1.70 | 1.72 | 1.75 | 0.56 | Quote |
| 1-1/2" (40 NB) | 6.12 | 0.75 | 2.88 | 2.75 | 1.90 | 4.50 | 4 × 3/4" | 2.63 | 1.13 | 1.19 | 1.95 | 1.97 | 1.98 | 0.62 | Quote |
| 2" (50 NB) | 6.50 | 0.81 | 3.62 | 3.31 | 2.38 | 5.00 | 8 × 5/8" | 2.69 | 1.25 | 1.31 | 2.44 | 2.46 | 2.50 | 0.69 | Quote |
| 2-1/2" (65 NB) | 7.50 | 0.94 | 4.12 | 3.94 | 2.88 | 5.88 | 8 × 3/4" | 2.94 | 1.44 | 1.50 | 2.94 | 2.97 | 3.00 | 0.75 | Quote |
| 3" (80 NB) | 8.25 | 1.06 | 5.00 | 4.62 | 3.50 | 6.62 | 8 × 3/4" | 3.06 | 1.63 | 1.69 | 3.57 | 3.60 | 3.63 | 0.81 | Quote |
| 3-1/2" (90 NB) | 9.00 | 1.12 | 5.50 | 5.25 | 4.00 | 7.25 | 8 × 3/4" | 3.13 | 1.69 | 1.75 | 4.07 | 4.10 | – | – | Quote |
| 4" (100 NB) | 10.00 | 1.19 | 6.19 | 5.75 | 4.50 | 7.88 | 8 × 3/4" | 3.32 | 1.82 | 1.88 | 4.57 | 4.60 | – | – | Quote |
| 5" (125 NB) | 11.00 | 1.31 | 7.31 | 7.00 | 5.56 | 9.25 | 8 × 3/4" | 3.82 | 1.94 | 2.00 | 5.66 | 5.69 | – | – | Quote |
| 6" (150 NB) | 12.50 | 1.38 | 8.50 | 8.12 | 6.63 | 10.62 | 12 × 3/4" | 3.82 | 2.00 | 2.06 | 6.72 | 6.75 | – | – | Quote |
| 8" (200 NB) | 15.00 | 1.56 | 10.62 | 10.25 | 8.63 | 13.00 | 12 × 7/8" | 4.32 | 2.38 | 2.44 | 8.72 | 8.75 | – | – | Quote |
| 10" (250 NB) | 17.50 | 1.81 | 12.75 | 12.62 | 10.75 | 15.25 | 16 × 1" | 4.56 | 2.56 | 3.75 | 10.88 | 10.92 | – | – | Quote |
| 12" (300 NB) | 20.50 | 1.94 | 15.00 | 14.75 | 12.75 | 17.75 | 16 × 1-1/8" | 5.06 | 2.82 | 4.00 | 12.88 | 12.92 | – | – | Quote |
| 14" (350 NB) | 23.00 | 2.06 | 16.25 | 16.75 | 14.00 | 20.25 | 20 × 1-1/8" | 5.56 | 2.94 | 4.38 | 14.14 | 14.18 | – | – | Quote |
| 16" (400 NB) | 25.50 | 2.19 | 18.50 | 19.00 | 16.00 | 22.50 | 20 × 1-1/4" | 5.69 | 3.19 | 4.75 | 16.16 | 16.19 | – | – | Quote |
| 18" (450 NB) | 28.00 | 2.31 | 21.00 | 21.00 | 18.00 | 24.75 | 24 × 1-1/4" | 6.19 | 3.44 | 5.12 | 18.18 | 18.20 | – | – | Quote |
| 20" (500 NB) | 30.50 | 2.44 | 23.00 | 23.12 | 20.00 | 27.00 | 24 × 1-1/4" | 6.32 | 3.69 | 5.50 | 20.20 | 20.25 | – | – | Quote |
| 24" (600 NB) | 36.00 | 2.69 | 27.25 | 27.62 | 24.00 | 32.00 | 24 × 1-1/2" | 6.56 | 4.13 | 6.00 | 24.25 | 24.25 | – | – | Quote |
What the letters mean
- OOutside diameter of the flange
- TFlange thickness, without the raised face
- YLength through hub, from flange face to hub end (differs for weld neck, slip-on and lap joint)
- XHub diameter at the base of the hub
- AHub diameter at the weld point, equal to pipe OD
- BBore. Slip-on and lap joint bores are fixed; weld neck bore matches the pipe schedule
- RRaised face diameter. Raised face height is 1.6 mm (Class 150, 300) or 6.4 mm (Class 600 and above)
- WBolt circle, also called PCD (pitch circle diameter)
- CSocket bore of a socket weld flange
- DSocket depth of a socket weld flange
- TₜThread length of a threaded flange (NPT)
Questions buyers ask
What is the outside diameter of a 6 inch Class 300 flange?
Per ASME B16.5, a 6" Class 300 flange has an outside diameter of 317.5 mm (12.50 in), a bolt circle of 269.7 mm and 12 bolts of 3/4".
Which flange types are made in Class 300?
Weld neck, lap joint and blind flanges in every listed size. Slip-on and threaded in all sizes, socket weld up to 3 inch.
Is the raised face included in these dimensions?
No. Thickness T and length through hub Y exclude the raised face, which is 1.6 mm (1/16 in) high for Class 300.
Can Teshi make Class 300 flanges in stainless, duplex or nickel alloys?
Yes. We manufacture Class 300 flanges in carbon steel (A105N, LF2), alloy steel (F11 to F91), stainless steel (F304L, F316L, F321), 904L, duplex, super duplex, nickel alloys and titanium, with EN 10204 3.1 certificates.
Get a quotation from the manufacturer
Send your BOQ, drawing or tender reference. You deal directly with the manufacturer.
- Reply from our estimation team, usually within one working day
- Carbon steel to titanium on one order
- EN 10204 3.1 or 3.2 certificates, third-party inspection welcome
- ISO 9001:2015 certified and IBR approved, since 1971
Drawings and BOQ spreadsheets are easiest by email. Mention your project name.