ASME B16.5 Class 2500 Lap Joint Flange Dimensions
Lap Joint flange dimensions to ASME B16.5 Class 2500 in millimetres: outside diameter, thickness, raised face, hub, length through hub, bolt circle and drilling, NPS ½" to 12". A lap joint flange is a loose backing flange used with a stub end. The flange rotates freely for easy bolt-hole alignment and can be in carbon steel while the wetted stub end is in stainless or alloy.
Key to dimensions
- O
- Outside diameter of flange
- tf
- Minimum flange thickness
- X
- Diameter of hub at base
- Y
- Length through hub (lap joint)
- W
- Bolt circle diameter
Lap joint flanges are made NPS ½ to 24 (to 12 in Class 2500).
ASME B16.5 Class 2500 lap joint flange dimensions (mm)
| NPSin | DN | OOutside dia | tfMin thickness | XHub dia | YThis type | WBolt circle | HolesNo. | Hole diamm | Boltin |
|---|---|---|---|---|---|---|---|---|---|
| ½" | 15 | 135 | 30.2 | 43 | 40 | 88.9 | 4 | 22.2 | ¾" |
| ¾" | 20 | 140 | 31.8 | 51 | 43 | 95.2 | 4 | 22.2 | ¾" |
| 1" | 25 | 160 | 35.0 | 57 | 48 | 108.0 | 4 | 25.4 | ⅞" |
| 1¼" | 32 | 185 | 38.1 | 73 | 52 | 130.2 | 4 | 28.6 | 1" |
| 1½" | 40 | 205 | 44.5 | 79 | 60 | 146.0 | 4 | 31.8 | 1⅛" |
| 2" | 50 | 235 | 50.9 | 95 | 70 | 171.4 | 8 | 28.6 | 1" |
| 2½" | 65 | 265 | 57.2 | 114 | 79 | 196.8 | 8 | 31.8 | 1⅛" |
| 3" | 80 | 305 | 66.7 | 133 | 92 | 228.6 | 8 | 34.9 | 1¼" |
| 4" | 100 | 355 | 76.2 | 165 | 108 | 273.0 | 8 | 41.3 | 1½" |
| 5" | 125 | 420 | 92.1 | 203 | 130 | 323.8 | 8 | 47.6 | 1¾" |
| 6" | 150 | 485 | 108.0 | 235 | 152 | 368.3 | 8 | 54.0 | 2" |
| 8" | 200 | 550 | 127.0 | 305 | 178 | 438.2 | 12 | 54.0 | 2" |
| 10" | 250 | 675 | 165.1 | 375 | 229 | 539.8 | 12 | 66.7 | 2½" |
| 12" | 300 | 760 | 184.2 | 441 | 254 | 619.1 | 12 | 73.0 | 2¾" |
Notes
- Dimensions are in millimetres unless stated otherwise.
- Flange thickness tf and length through hub Y do not include the 7 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.
- ASME B16.5 has no Class 2500 slip-on or socket weld flange; the slip-on column applies to threaded flanges only.
- 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 2500 flange types
Lap Joint flange dimensions in other classes
FAQ
Class 2500 lap joint flange: common questions
What is the outside diameter of a 4" Class 2500 lap joint flange?
355 mm, with a minimum thickness tf of 76.2 mm, bolt circle 273.0 mm and 8 bolt holes of 41.3 mm.
Which sizes are covered?
This chart covers NPS ½" to 12" (DN 15 to 300). Lap joint flanges are made NPS ½ to 24 (to 12 in Class 2500).
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 2500 lap joint 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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