ASME B16.5 Class 150 Flange Dimensions
This chart gives the dimensions of ASME B16.5 Class 150 pipe flanges in millimetres for NPS ½" to 24". It covers weld neck, slip-on, blind, socket weld, threaded and lap joint flanges, with drilling, stud bolt lengths and approximate weights.
For carbon steel flanges in ASTM A105 (material group 1.1) the Class 150 working pressure is 19.6 bar at −29 to 38 °C, falling as temperature rises — see the pressure–temperature ratings. Teshi Group manufactures these flanges as an OEM in carbon, stainless and alloy steel.
Key to dimensions
- O
- Outside diameter of flange
- tf
- Minimum flange thickness (also the blind flange thickness), excluding the raised face
- R
- Diameter of raised face
- X
- Hub diameter at base
- A
- Hub diameter at the welding end of a weld neck flange (pipe outside diameter)
- Y
- Length through hub — given separately for weld neck, slip-on / threaded / socket weld and lap joint flanges
- W
- Bolt circle diameter
- Holes
- Number and diameter of bolt holes
- Bolt
- Nominal bolt diameter in inches
ASME B16.5 Class 150 flange types — drawings
The table covers every flange type of this class. Each drawing shows which dimensions apply; open a type for its own chart.
ASME B16.5 Class 150 Flange dimensions — tables
Class 150 flange dimensions (mm)
| NPSin | DN | OOutside dia | tfMin thickness | RRaised face dia | XHub dia | AHub at weld | YWeld neck | YSlip-on / Thr / SW | YLap joint | WBolt circle | HolesNo. | Hole diamm | Boltin |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ½" | 15 | 90 | 9.6 | 34.9 | 30 | 21.3 | 46 | 14 | 16 | 60.3 | 4 | 15.9 | ½" |
| ¾" | 20 | 100 | 11.2 | 42.9 | 38 | 26.7 | 51 | 14 | 16 | 69.9 | 4 | 15.9 | ½" |
| 1" | 25 | 110 | 12.7 | 50.8 | 49 | 33.4 | 54 | 16 | 17 | 79.4 | 4 | 15.9 | ½" |
| 1¼" | 32 | 115 | 14.3 | 63.5 | 59 | 42.2 | 56 | 19 | 21 | 88.9 | 4 | 15.9 | ½" |
| 1½" | 40 | 125 | 15.9 | 73.0 | 65 | 48.3 | 60 | 21 | 22 | 98.4 | 4 | 15.9 | ½" |
| 2" | 50 | 150 | 17.5 | 92.1 | 78 | 60.3 | 62 | 24 | 25 | 120.7 | 4 | 19.1 | ⅝" |
| 2½" | 65 | 180 | 20.7 | 104.8 | 90 | 73.0 | 68 | 27 | 29 | 139.7 | 4 | 19.1 | ⅝" |
| 3" | 80 | 190 | 22.3 | 127.0 | 108 | 88.9 | 68 | 29 | 30 | 152.4 | 4 | 19.1 | ⅝" |
| 3½" | 90 | 215 | 22.3 | 139.7 | 122 | 101.6 | 70 | 30 | 32 | 177.8 | 8 | 19.1 | ⅝" |
| 4" | 100 | 230 | 22.3 | 157.2 | 135 | 114.3 | 75 | 32 | 33 | 190.5 | 8 | 19.1 | ⅝" |
| 5" | 125 | 255 | 22.3 | 185.7 | 164 | 141.3 | 87 | 35 | 36 | 215.9 | 8 | 22.2 | ¾" |
| 6" | 150 | 280 | 23.9 | 215.9 | 192 | 168.3 | 87 | 38 | 40 | 241.3 | 8 | 22.2 | ¾" |
| 8" | 200 | 345 | 27.0 | 269.9 | 246 | 219.1 | 100 | 43 | 44 | 298.5 | 8 | 22.2 | ¾" |
| 10" | 250 | 405 | 28.6 | 323.8 | 305 | 273.0 | 100 | 48 | 49 | 362.0 | 12 | 25.4 | ⅞" |
| 12" | 300 | 485 | 30.2 | 381.0 | 365 | 323.8 | 113 | 54 | 56 | 431.8 | 12 | 25.4 | ⅞" |
| 14" | 350 | 535 | 33.4 | 412.8 | 400 | 355.6 | 125 | 56 | 79 | 476.3 | 12 | 28.6 | 1" |
| 16" | 400 | 595 | 35.0 | 469.9 | 457 | 406.4 | 125 | 62 | 87 | 539.8 | 16 | 28.6 | 1" |
| 18" | 450 | 635 | 38.1 | 533.4 | 505 | 457.0 | 138 | 67 | 97 | 577.9 | 16 | 31.8 | 1⅛" |
| 20" | 500 | 700 | 41.3 | 584.2 | 559 | 508.0 | 143 | 71 | 103 | 635.0 | 20 | 31.8 | 1⅛" |
| 24" | 600 | 815 | 46.1 | 692.2 | 663 | 610.0 | 151 | 81 | 111 | 749.3 | 20 | 34.9 | 1¼" |
Class 150 bolting and approximate weights
| NPSin | StudsNo. | Stud diain | Stud lengthRaised face | Stud lengthRing joint | Weld neckkg, approx. | Slip-onkg, approx. | Blindkg, approx. |
|---|---|---|---|---|---|---|---|
| ½" | 4 | ½" | 55 | — | — | 0.5 | 0.5 |
| ¾" | 4 | ½" | 65 | — | — | — | — |
| 1" | 4 | ½" | 65 | 75 | 1.1 | 0.9 | 0.9 |
| 1¼" | 4 | ½" | 70 | 85 | 1.4 | 1.1 | 1.2 |
| 1½" | 4 | ½" | 70 | 85 | 1.8 | 1.4 | 1.6 |
| 2" | 4 | ⅝" | 85 | 95 | 2.6 | 2.3 | 2.6 |
| 2½" | 4 | ⅝" | 90 | 100 | 4.3 | 3.4 | — |
| 3" | 4 | ⅝" | 90 | 100 | 5.2 | 3.9 | — |
| 3½" | 8 | ⅝" | 90 | 100 | 5.5 | 5.0 | 5.9 |
| 4" | 8 | ⅝" | 90 | 100 | 7.3 | 5.8 | 7.4 |
| 5" | 8 | ¾" | 95 | 110 | 8.9 | 6.2 | 8.8 |
| 6" | 8 | ¾" | 100 | 115 | 11.3 | 7.4 | 11.3 |
| 8" | 8 | ¾" | 110 | 120 | 17.7 | 12.4 | 19.9 |
| 10" | 12 | ⅞" | 115 | 125 | 24.8 | 17.1 | 29.4 |
| 12" | 12 | ⅞" | 120 | 135 | 39.0 | 27.7 | 43.7 |
| 14" | 12 | 1" | 135 | 145 | 51.7 | 35.2 | 59.4 |
| 16" | 16 | 1" | 135 | 145 | 64.4 | 42.2 | 77.1 |
| 18" | 16 | 1⅛" | 145 | 160 | 74.8 | 49.7 | 94.8 |
| 20" | 20 | 1⅛" | 160 | 170 | 89.4 | 65.5 | 123 |
| 24" | 20 | 1¼" | 170 | 185 | 120 | 90.5 | 188 |
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.
Equivalent and related standards to ASME B16.5 Class 150 Flange Dimensions
All equivalents| Region | Standard | Relationship |
|---|---|---|
| Europe | EN 1759-1 Class 150 | Class-rated steel flanges based on ASME B16.5 dimensions (metric bolting) |
| China | HG/T 20615 Class 150 (PN 20) | Chemical-industry Class flanges — ASME B16.5 dimensions |
| China | GB/T 9124.2 Class 150 | National standard steel pipe flanges, Class series — ASME B16.5 dimensions |
| China | SH/T 3406 Class 150 | Petrochemical steel pipe flanges — ASME B16.5 dimensions |
| UK | BS 1560 Class 150 (withdrawn) | Former British adoption of ASME B16.5 |
| International | ISO 7005-1 Class 150 series | ISO steel flanges, Class designations aligned with ASME B16.5 |
| USA | ASME B16.47 Series A / MSS SP-44 | Same classes for NPS 26 and larger |
| Japan | JIS B2220 (K ratings) | Not interchangeable — JIS uses its own 5K–30K pressure ratings and dimensions |
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.
Dimension finder
Pick a product, standard and size — or just type — to see every dimension and download a watermarked PDF for that one size.
ASME B16.5 Class 150 Flange Dimensions — size by size
Every size has its own page with a drawing, mm and inch values and a one-size PDF.
FAQ
ASME B16.5 Class 150 flange dimensions: common questions
What is the pressure rating of a Class 150 flange?
For ASTM A105 carbon steel (ASME B16.5 material group 1.1) a Class 150 flange is rated 19.6 bar at −29 to 38 °C. The rating depends on material group and decreases with temperature.
What are the dimensions of a 4 inch Class 150 flange?
A NPS 4" Class 150 flange has an outside diameter of 230 mm, a minimum thickness of 22.3 mm, a bolt circle of 190.5 mm and 8 bolt holes for ⅝" bolts.
Does the flange thickness include the raised face?
No. For Class 150 the 2 mm raised face is additional to the minimum flange thickness tf shown in the chart.
Related products, data sheets and standards
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