01
Weld Neck Flange
ASME B16.5 Class 150 Flange Dimensions
02
Threaded Flange
03
Slip On Flange
04
Lap Joint Flange
05
Socket Weld Flange
06
Blind Flange
Texas Flange been providin' ASME B16.5 (ANSI) Class 150 flanges since 1986, and the table down below gives the full 150# dimensions for ever' nominal size from 1/2" clear through 24". For drawings, see our CAD and 3D flange drawings, or holler at us for a quote.
Filter by
| Nom. Pipe Size | O | T | TJ | R | X | #/Dia of Holesa | Bolt Circle Dia | B | B2b | B3 | H | L | L2 | L3c | r | D | Thr |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ½ | 3.50 | 0.38 | 0.44 | 1.38 | 1.19 | 4-0.62 | 2.38 | 0.88 | 0.62 | 0.90 | 0.84 | 0.56 | 1.81 | 0.62 | 0.12 | 0.38 | 0.62 |
| ¾ | 3.88 | 0.44 | 0.50 | 1.69 | 1.50 | 4-0.62 | 2.75 | 1.09 | 0.82 | 1.11 | 1.05 | 0.56 | 2.00 | 0.62 | 0.12 | 0.44 | 0.62 |
| 1 | 4.25 | 0.50 | 0.56 | 2.00 | 1.94 | 4-0.62 | 3.12 | 1.36 | 1.05 | 1.38 | 1.32 | 0.62 | 2.12 | 0.69 | 0.12 | 0.50 | 0.69 |
| 1¼ | 4.62 | 0.56 | 0.62 | 2.50 | 2.31 | 4-0.62 | 3.50 | 1.70 | 1.38 | 1.72 | 1.66 | 0.75 | 2.19 | 0.81 | 0.19 | 0.56 | 0.81 |
| 1½ | 5.00 | 0.62 | 0.69 | 2.88 | 2.56 | 4-0.62 | 3.88 | 1.95 | 1.61 | 1.97 | 1.90 | 0.81 | 2.38 | 0.88 | 0.25 | 0.62 | 0.88 |
| 2 | 6.00 | 0.69 | 0.75 | 3.62 | 3.06 | 4-0.75 | 4.75 | 2.44 | 2.07 | 2.46 | 2.38 | 0.94 | 2.44 | 1.00 | 0.31 | 0.69 | 1.00 |
| 2½ | 7.00 | 0.81 | 0.88 | 4.12 | 3.56 | 4-0.75 | 5.50 | 2.94 | 2.47 | 2.97 | 2.88 | 1.06 | 2.69 | 1.12 | 0.31 | 0.75 | 1.12 |
| 3 | 7.50 | 0.88 | 0.94 | 5.00 | 4.25 | 4-0.75 | 6.00 | 3.57 | 3.07 | 3.60 | 3.50 | 1.12 | 2.69 | 1.19 | 0.38 | 0.81 | 1.19 |
| 3½ | 8.50 | 0.88 | 0.94 | 5.50 | 4.81 | 8-0.75 | 7.00 | 4.07 | 3.55 | 4.10 | 4.00 | 1.19 | 2.75 | 1.25 | 0.38 | 0.88 | 1.25 |
| 4 | 9.00 | 0.88 | 0.94 | 6.19 | 5.31 | 8-0.75 | 7.50 | 4.57 | 4.03 | 4.60 | 4.50 | 1.25 | 2.94 | 1.31 | 0.44 | 0.94 | 1.31 |
| 5 | 10.00 | 0.88 | 0.94 | 7.31 | 6.44 | 8-0.88 | 8.50 | 5.66 | 5.05 | 5.69 | 5.56 | 1.38 | 3.44 | 1.44 | 0.44 | 0.94 | 1.44 |
| 6 | 11.00 | 0.94 | 1.00 | 8.50 | 7.56 | 8-0.88 | 9.50 | 6.72 | 6.07 | 6.75 | 6.63 | 1.50 | 3.44 | 1.56 | 0.50 | 1.06 | 1.56 |
| 8 | 13.50 | 1.06 | 1.12 | 10.62 | 9.69 | 8-0.88 | 11.75 | 8.72 | 7.98 | 8.75 | 8.63 | 1.69 | 3.94 | 1.75 | 0.50 | 1.25 | 1.75 |
| 10 | 16.00 | 1.12 | 1.19 | 12.75 | 12.00 | 12-1.00 | 14.25 | 10.88 | 10.02 | 10.92 | 10.75 | 1.88 | 3.94 | 1.94 | 0.50 | 1.31 | 1.94 |
| 12 | 19.00 | 1.19 | 1.25 | 15.00 | 14.38 | 12-1.00 | 17.00 | 12.88 | 12.00 | 12.92 | 12.75 | 2.12 | 4.44 | 2.19 | 0.50 | 1.56 | 2.19 |
| 14 | 21.00 | 1.31 | 1.38 | 16.25 | 15.75 | 12-1.12 | 18.75 | 14.14 | 13.25 | 14.18 | 14.00 | 2.19 | 4.94 | 3.12 | 0.50 | 1.63 | 2.25 |
| 16 | 23.50 | 1.38 | 1.44 | 18.50 | 18.00 | 16-1.12 | 21.25 | 16.16 | 15.25 | 16.19 | 16.00 | 2.44 | 4.94 | 3.44 | 0.50 | 1.75 | 2.50 |
| 18 | 25.00 | 1.50 | 1.56 | 21.00 | 19.88 | 16-1.25 | 22.75 | 18.18 | 17.25 | 18.20 | 18.00 | 2.62 | 5.44 | 3.81 | 0.50 | 1.94 | 2.69 |
| 20 | 27.50 | 1.62 | 1.69 | 23.00 | 22.00 | 20-1.25 | 25.00 | 20.20 | 19.25 | 20.25 | 20.00 | 2.81 | 5.62 | 4.06 | 0.50 | 2.13 | 2.88 |
| 22 | 29.50 | 1.75 | 1.81 | 25.25 | 24.25 | 20-1.38 | 27.25 | 22.22 | 21.25 | 22.25 | 22.00 | 3.07 | 5.82 | 4.25 | 0.50 | 2.38 | 3.13 |
| 24 | 32.00 | 1.81 | 1.88 | 27.25 | 26.12 | 20-1.38 | 29.50 | 24.25 | 23.25 | 24.25 | 24.00 | 3.19 | 5.94 | 4.38 | 0.50 | 2.50 | 3.25 |
Dimensions are in inches.
(a)- Bolt hole diameter 1/8 in. larger than bolt diameter. (b)- Standard bore dimensions provided. See bore chart for other wall thicknesses. (c)- This dimension is commonly associated with “true” lap joints. Industry standard is to make to the slip on length through the hub.
4 Inch Weld Neck Flange Dimensions by Class
The 4 inch weld neck is one of the most common flanges we ship. The Class 150 dimensions are in the table above. Here is how they change as the class goes up. All values in inches.
| Class | Outside diameter | Bolt circle | Bolt holes | Studs (count x diameter) | Stud length, raised face |
|---|---|---|---|---|---|
| 150 | 9.00 | 7.50 | 8 at 0.75 | 8 x 0.63 | 3-1/2 |
| 300 | 10.00 | 7.88 | 8 at 0.88 | 8 x 0.75 | 4-1/2 |
| 600 | 10.75 | 8.50 | 8 at 1.00 | 8 x 0.88 | 5-3/4 |
| 900 | 11.50 | 9.25 | 8 at 1.25 | 8 x 1.13 | 6-3/4 |
| 1500 | 12.25 | 9.50 | 8 at 1.38 | 8 x 1.25 | 7-3/4 |
| 2500 | 14.00 | 10.75 | 8 at 1.63 | 8 x 1.50 | 10 |
Hub and bore dimensions vary by pipe schedule. See the weld neck flange bore chart, the flange bolt chart for stud sizes, or download a 4 inch Class 150 weld neck CAD drawing from our CAD and 3D flange drawings library.
Questions Folks Ask Us
- What kinda pressure can a Class 150 flange handle?
- An ASME B16.5 Class 150 flange in A105 carbon steel is rated to 285 psi at 100°F. Even with dat "150" in the name, the workin' pressure is 285 psi at ambient temperature and it drops down as the temperature rises (to 'bout 170 psi at 500°F). Y'all always make sure to confirm the pressure-temperature rating for your specific material grade.
- What sizes do dem Class 150 flanges come in?
- ASME B16.5 covers Class 150 flanges from NPS 1/2" clear up to 24". For dem larger diameters, the equivalent standard is ASME B16.47 Series A and B, yessir.
- What's the difference 'tween Class 150 and Class 300?
- Class 300 carries a higher pressure rating than Class 150 (740 psi vs 285 psi at 100°F in A105) and uses a thicker flange with a different, non-interchangeable bolt pattern. Choose the class from the pressure-temperature rating your service requires.
- What flange types are available in Class 150?
- Class 150 is available in every ASME B16.5 type we produce: weld neck, slip-on, blind, threaded, socket weld, and lap joint, in raised face (RF) or flat face (FF).
- How many bolts does a Class 150 flange use?
- It depends on the size, y’all. ASME B16.5 bolt-hole counts are always a multiple of four, from 4 bolts on small sizes up to 20 on a 24" flange. See our flange bolt chart for the exact bolt count and bolt size for each diameter, and the table on this page for the bolt circle.
- What are the bolt hole dimensions for a Class 150 flange?
- Bolt hole dimensions for an ASME B16.5 Class 150 flange are set by the nominal pipe size. Ever' size calls out a bolt circle diameter, a bolt hole diameter, and a bolt count. A 4 inch Class 150 flange, for example, has 8 holes of 0.75 inch diameter on a 7.50 inch bolt circle, with a 9.00 inch outside diameter. Y'all can find the full bolt hole dimensions for ever' size from 1/2 inch clear through 24 inch in the Class 150 dimension table on this here page, and bolt and stud sizes are over on the Texas Flange bolt chart.
- What does the # symbol mean in 150# flange?
- Dat # symbol is just shorthand for pressure class, so 150# and Class 150 mean the exact same thing. It's a class designation, not a weight and not a direct pressure ratin'. A Class 150 carbon steel flange in Material Group 1.1 is rated to 285 psig at -20 to 100 degrees F, and dat ratin' falls as the temperature rises.
- What's the difference 'tween Class 150 and Class 600 flanges?
- Class 600 flanges are rated for roughly five times the working pressure of Class 150 at the same temperature. In Material Group 1.1 at -20 to 100 degrees F, Class 150 is rated to 285 psig and Class 600 to 1480 psig. Class 600 flanges are thicker, heavier, and in most sizes use larger bolting, so the two are not interchangeable even where bolt circles appear similar. See the Class 600 dimension tables.
- Are Class 150 flange dimensions the same as ANSI B16.5 and ASME B16.5?
- Yessir. ANSI B16.5 and ASME B16.5 are talkin' 'bout the exact same standard, so a flange called ANSI B16.5 Class 150 and one called ASME B16.5 Class 150 got the exact same dimensions. ANSI does the accreditin' and ASME puts out the standard. Dem dimensions on this page work just fine no matter which name y'all use.
