ASME B16.5 Class 300 Blind Flange Dimensions
Blind flange dimensions to ASME B16.5 Class 300 in millimetres: outside diameter, thickness, raised face, hub, length through hub, bolt circle and drilling, NPS ½" to 24". A blind flange is a solid disc that closes the end of a pipe, valve or vessel nozzle. It has the same outside diameter, thickness and drilling as the other flange types of the same size and class.
Key to dimensions
- O
- Outside diameter of flange
- tf
- Minimum flange thickness
- R
- Diameter of raised face
- W
- Bolt circle diameter
ASME B16.5 Class 300 blind flange dimensions (mm)
| NPSin | DN | OOutside dia | tfMin thickness | RRaised face dia | WBolt circle | HolesNo. | Hole diamm | Boltin |
|---|---|---|---|---|---|---|---|---|
| ½" | 15 | 95 | 12.7 | 34.9 | 66.7 | 4 | 15.9 | ½" |
| ¾" | 20 | 115 | 14.3 | 42.9 | 82.6 | 4 | 19.1 | ⅝" |
| 1" | 25 | 125 | 15.9 | 50.8 | 88.9 | 4 | 19.1 | ⅝" |
| 1¼" | 32 | 135 | 17.5 | 63.5 | 98.4 | 4 | 19.1 | ⅝" |
| 1½" | 40 | 155 | 19.1 | 73.0 | 114.3 | 4 | 22.2 | ¾" |
| 2" | 50 | 165 | 20.7 | 92.1 | 127.0 | 8 | 19.1 | ⅝" |
| 2½" | 65 | 190 | 23.9 | 104.8 | 149.2 | 8 | 22.2 | ¾" |
| 3" | 80 | 210 | 27.0 | 127.0 | 168.3 | 8 | 22.2 | ¾" |
| 3½" | 90 | 230 | 28.6 | 139.7 | 184.2 | 8 | 22.2 | ¾" |
| 4" | 100 | 255 | 30.2 | 157.2 | 200.0 | 8 | 22.2 | ¾" |
| 5" | 125 | 280 | 33.4 | 185.7 | 235.0 | 8 | 22.2 | ¾" |
| 6" | 150 | 320 | 35.0 | 215.9 | 269.9 | 12 | 22.2 | ¾" |
| 8" | 200 | 380 | 39.7 | 269.9 | 330.2 | 12 | 25.4 | ⅞" |
| 10" | 250 | 445 | 46.1 | 323.8 | 387.4 | 16 | 28.6 | 1" |
| 12" | 300 | 520 | 49.3 | 381.0 | 450.8 | 16 | 31.8 | 1⅛" |
| 14" | 350 | 585 | 52.4 | 412.8 | 514.4 | 20 | 31.8 | 1⅛" |
| 16" | 400 | 650 | 55.6 | 469.9 | 571.5 | 20 | 34.9 | 1¼" |
| 18" | 450 | 710 | 58.8 | 533.4 | 628.6 | 24 | 34.9 | 1¼" |
| 20" | 500 | 775 | 62.0 | 584.2 | 685.8 | 24 | 34.9 | 1¼" |
| 24" | 600 | 915 | 68.3 | 692.2 | 812.8 | 24 | 41.3 | 1½" |
Class 300 blind flange bolting and approximate weight
| NPSin | StudsNo. | Stud diain | Stud lengthRF, mm | Weightkg, approx. |
|---|---|---|---|---|
| ½" | 4 | ½" | 65 | — |
| ¾" | 4 | ⅝" | 75 | — |
| 1" | 4 | ⅝" | 75 | 1.4 |
| 1¼" | 4 | ⅝" | 85 | — |
| 1½" | 4 | ¾" | 90 | — |
| 2" | 8 | ⅝" | 90 | — |
| 2½" | 8 | ¾" | 100 | 4.8 |
| 3" | 8 | ¾" | 110 | 6.8 |
| 3½" | 8 | ¾" | 110 | 9.5 |
| 4" | 8 | ¾" | 115 | 12.0 |
| 5" | 8 | ¾" | 120 | 16.0 |
| 6" | 12 | ¾" | 120 | 21.2 |
| 8" | 12 | ⅞" | 140 | 34.6 |
| 10" | 16 | 1" | 160 | 55.3 |
| 12" | 16 | 1⅛" | 170 | 78.9 |
| 14" | 20 | 1⅛" | 180 | 107 |
| 16" | 20 | 1¼" | 190 | 139 |
| 18" | 24 | 1¼" | 195 | 177 |
| 20" | 24 | 1¼" | 205 | 223 |
| 24" | 24 | 1½" | 230 | 342 |
Notes
- Dimensions are in millimetres unless stated otherwise.
- Flange thickness tf and length through hub Y do not include the 2 mm raised face.
- Blind flanges have the same outside diameter, thickness tf and drilling as the other flange types of the same size and class.
- The bore of a weld neck or socket weld flange is machined to match the inside diameter of the pipe schedule stated in the order.
- Bolt holes are tabulated in inches in ASME B16.5; the millimetre values shown are direct conversions (bolt diameter plus ⅛").
- Stud bolt lengths do not include the height of the points. Weights are approximate catalogue values and vary with bore and manufacturer.
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.
Other Class 300 flange types
Blind flange dimensions in other classes
FAQ
Class 300 blind flange: common questions
What is the outside diameter of a 4" Class 300 blind flange?
255 mm, with a minimum thickness tf of 30.2 mm, bolt circle 200.0 mm and 8 bolt holes of 22.2 mm.
Which sizes are covered?
This chart covers NPS ½" to 24" (DN 15 to 600).
Are dimensions the same for all flange types of one class?
Outside diameter, thickness and drilling are the same for every flange type of the same size and class; the hub length Y, hub and bore differ by type.
Does Teshi Group manufacture Class 300 blind flanges?
Yes. Teshi Group is an OEM manufacturer of ASME B16.5 flanges in India, in carbon, low-temperature, chrome-moly, stainless, duplex, super duplex and nickel alloys, with EN 10204 3.1 certificates and IBR certification on request.
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