Class 300 Flange Dimensions
Table of Content
- Class 300 Flange Dimensions
- ANSI 300 LB Flange Pressure Rating
- 300# Flange Thickness
- Class 300 Flange Number Of Holes
- Application of ANSI B16.5 Class 300 Flange
- What Is The Difference Between Class 300 And 600 Flange
- Class 300 Flange Working Pressure
- Class 300 Flange Gasket Dimensions in mm
- Class 300 Flange Weight
- Class 300 LB Flange Standard
- Types Of Class 300 Forged Flange
Class 300 flange are pressure-level classifications based on ASME B16.5 standard. 300 flange pressure ratings can be indicated in 300#, Class 300, 300 Lb, 300 Lbs. 300 LB flange ideal for high pressure to moderate pipelines. Guide to class 300 flange dimensions.
| NPS | Hub Diameter at Base | Flange Outside Diameter | Flange Thickness | Raised Face Diameter | Length Thru Hub | ||
| Lap Joint Flange | Weld Neck Flange | Socket Weld Flange, Slip On Flange, Threaded Flange | |||||
| X | O | Q | R | Y | Y | Y | |
| 24 | 27-5/8 | 36 | 2-3/4 | 27-1/4 | 6 | 6-5/8 | 4-3/16 |
| 20 | 23-1/8 | 30-1/2 | 2-1/2 | 23 | 5-1/2 | 6-3/8 | 3-3/4 |
| 18 | 21 | 28 | 2-3/8 | 21 | 5-1/8 | 6-1/4 | 3-1/2 |
| 16 | 19 | 25-1/2 | 2-1/4 | 18-1/2 | 4-3/4 | 5-3/4 | 3-1/4 |
| 14 | 16-3/4 | 23 | 2-1/8 | 16-1/4 | 4-3/8 | 5-5/8 | 3 |
| 12 | 14-3/4 | 20-1/2 | 2 | 15 | 4 | 5-1/8 | 2-7/8 |
| 10 | 12-5/8 | 17-1/2 | 1-7/8 | 12-3/4 | 3-3/4 | 4-5/8 | 2-5/8 |
| 8 | 10-1/4 | 15 | 1-5/8 | 10-5/8 | 2-7/16 | 4-3/8 | 2-7/16 |
| 6 | 8-1/8 | 12-1/2 | 1-7/16 | 8-1/2 | 2-1/16 | 3-7/8 | 2-1/16 |
| 5 | 7 | 11 | 1-3/8 | 7-5/16 | 2 | 3-7/8 | 2 |
| 4 | 5-3/5 | 10 | 1-1/4 | 6-3/16 | 1-7/8 | 3-3/8 | 1-7/8 |
| 3-1/2 | 5-1/4 | 9 | 1-3/16 | 5-1/2 | 1-3/4 | 3-3/16 | 1-3/4 |
| 3 | 4-5/8 | 8-1/4 | 1-1/8 | 5 | 1-11/16 | 3-1/8 | 1-11/16 |
| 2-1/2 | 3-15/16 | 7-1/2 | 1 | 4-1/8 | 1-1/2 | 3 | 1-1/2 |
| 2 | 3-5/16 | 6-1/2 | 7/8 | 3-5/8 | 1-5/16 | 2-3/4 | 1-5/16 |
| 1-1/2 | 2-3/4 | 6-1/8 | 13/16 | 2-7/8 | 1-3/16 | 2-11/16 | 1-3/16 |
| 1-1/4 | 2-1/2 | 5-1/4 | 3/4 | 2-1/2 | 1-1/16 | 2-9/16 | 1-1/16 |
| 1 | 2-1/8 | 4-7/8 | 11/16 | 2 | 1-1/16 | 2-7/16 | 1-1/16 |
| 3/4 | 1-7/8 | 4-5/8 | 5/8 | 1-11/16 | 1 | 2-1/4 | 1 |
| 1/2 | 1-1/2 | 3-3/4 | 9/16 | 1-3/8 | 7/8 | 2-1/16 | 7/8 |
| Nominal Pipe Size | Bore and Diameter | Socket Depth | Diameter of Hub at Bevel | Fillet Radius | ||
| Lap Joint Flange | Slip On Flange & Socket Weld Flange | Welding Neck Flange and Socket Weld Flange | ||||
| B | W | J | Z | H | r | |
| 24 | 24.25 | 24.25 | 23.25 | – | 24.00 | 1/2 |
| 20 | 20.25 | 20.20 | 19.25 | – | 20.00 | 1/2 |
| 18 | 18.20 | 18.18 | 17.25 | – | 18.00 | 1/2 |
| 16 | 16.19 | 16.16 | 15.25 | – | 16.00 | 1/2 |
| 14 | 14.18 | 14.14 | 13.25 | – | 14.00 | 1/2 |
| 12 | 12.92 | 12.88 | 12.00 | – | 12.75 | 1/2 |
| 10 | 10.92 | 10.88 | 10.02 | – | 10.75 | 1/2 |
| 8 | 8.75 | 8.72 | 7.98 | – | 8.63 | 1/2 |
| 6 | 6.75 | 6.72 | 6.07 | – | 6.63 | 1/2 |
| 5 | 5.69 | 5.66 | 5.05 | – | 5.56 | 7/16 |
| 4 | 4.60 | 4.57 | 4.03 | 15/16 | 4.50 | 7/16 |
| 3-1/2 | 4.10 | 4.07 | 3.55 | 7/8 | 4.00 | 3/8 |
| 3 | 3.60 | 3.57 | 3.07 | 13/16 | 3.50 | 3/8 |
| 2-1/2 | 2.97 | 2.94 | 2.47 | 3/4 | 2.88 | 5/16 |
| 2 | 2.46 | 2.44 | 2.07 | 11/16 | 2.38 | 5/16 |
| 1-1/2 | 1.97 | 1.95 | 1.61 | 5/8 | 1.90 | 1/4 |
| 1-1/4 | 1.72 | 1.70 | 1.38 | 9/16 | 1.66 | 3/16 |
| 1 | 1.38 | 1.36 | 1.05 | 1/2 | 1.32 | 1/8 |
| 3/4 | 1.11 | 1.09 | .82 | 7/16 | 1.05 | 1/8 |
| 1/2 | .90 | .88 | .62 | 3/8 | .84 | 1/8 |
Understanding 300 LB Flange Pressure Rating
ANSI 300 LB Flange Pressure Rating
| Temperature | Class 300 Flange Pressure Rating |
| 475°C | 17.4 bar |
| 450°C | 23.0 bar |
| 425°C | 28.8 bar |
| 400°C | 34.7 bar |
| 375°C | 36.4 bar |
| 350°C | 37.6 bar |
| 300°C | 39.8 bar |
| 250°C | 41.9 bar |
| 200°C | 43.8 bar |
| 150°C | 45.1 bar |
| 100°C | 46.6 bar |
| 50°C | 50.1bar |
| -29 – 38°C | 51.1 bar |
Check 300# Flange Thickness and Bolt Holes as per ASME B16.5
| Size | Thickness | Outer Diameter |
|---|---|---|
| 24 | 2.750 | 36.00 |
| 20 | 2.500 | 30.50 |
| 18 | 2.375 | 28.00 |
| 16 | 2.250 | 25.50 |
| 14 | 2.125 | 23.00 |
| 12 | 2.000 | 20.50 |
| 10 | 1.875 | 17.50 |
| 8 | 1.625 | 15.00 |
| 6 | 1.438 | 12.50 |
| 4 | 1.250 | 10.00 |
| 3.5 | 1.188 | 9.00 |
| 3 | 1.125 | 8.25 |
| 2.5 | 1.000 | 7.50 |
| 2 | 0.875 | 6.50 |
| 1.5 | 0.813 | 6.13 |
| 1.25 | 0.750 | 5.25 |
| 1 | 0.688 | 4.88 |
| 0.75 | 0.625 | 4.63 |
| 0.5 | 0.563 | 3.75 |
Class 300 Flange Number Of Holes
| Class | Diameter Of Bolt Circle | Bolt Holes Number |
| Class 300 | 26″ | 12 |
Class 300 Pipe Flange Used in Petrochemical and Marine Application
Application of ANSI B16.5 Class 300 Flange
What Is The Difference Between Class 300 And 600 Flange
- 300 LB flange are designed for low pressure applications.
- Class 600 flanges are designed for high pressure applications
- MPa = 515 (min)
- 300# flanges temperature is 570 psi
- 600 lb flange temperature is 1,150 psi
- 600# flanges are generally thicker than 300 lbs flanges
- 300# flanges are used in water distribution and chemical processing
- 600 lbs flanges are used in oil and gas production and industrial applications
Class 300 Flange Working Pressure
| Temperature | Class 300 Stainless Steel 316 Flange (psig) | Class 300 Carbon Steel Flange (psig) |
| 800°F | 260 | Not Recommended |
| 600°F | 410 | 425 |
| 400°F | 540 | 580 |
| 200°F | 620 | 680 |
| -20 to 100°F | 720 | 740 |
Class 300 Flange Gasket Dimensions in mm
| Class 300 Full Face Gasket | ||||
| Nominal Bore | Bolt Holes Number | Holes Diameter | Diameter of Bolt Circle | O.D. |
| 24 | 24 | 1 5/8 | 32 | 36 |
| 20 | 24 | 1 3/8 | 27 | 30 1/2 |
| 18 | 24 | 1 3/8 | 24 3/4 | 28 |
| 16 | 20 | 1 3/8 | 22 1/2 | 25 1/2 |
| 14 | 20 | 1 1/4 | 20 1/4 | 23 |
| 12 | 16 | 1 1/4 | 17 3/4 | 20 1/2 |
| 10 | 16 | 1 1/8 | 15 1/4 | 17 1/2 |
| 8 | 12 | 1 1/8 | 13 | 15 |
| 6 | 12 | 7/8 | 10 5/8 | 12 1/2 |
| 5 | 8 | 7/8 | 9 1/4 | 11 |
| 4 | 8 | 7/8 | 7 7/8 | 10 |
| 3 1/2 | 8 | 7/8 | 7 1/4 | 9 |
| 3 | 8 | 7/8 | 6 5/8 | 8 1/4 |
| 2 1/2 | 8 | 7/8 | 5 7/8 | 7 1/2 |
| 2 | 8 | 3/4 | 5 | 6 1/2 |
| 1 1/2 | 4 | 7/8 | 4 1/2 | 6 1/8 |
| 1 1/4 | 4 | 3/4 | 3 7/8 | 5 1/4 |
| 1 | 4 | 3/4 | 3 1/2 | 4 7/8 |
| 3/4 | 4 | 3/4 | 3 1/4 | 4 5/8 |
| NPS | WeldNeck Flange | Blind Flange | Slip On Flange | Socket Weld Flange |
| 24 | 261 | 360 | 220.5 | 213.8 |
| 22 | 209.3 | 288 | 166.5 | 166.5 |
| 20 | 180 | 231.8 | 141.8 | 141.8 |
| 18 | 144 | 186.3 | 113.9 | 112.5 |
| 16 | 112.5 | 141.8 | 94.5 | 85.5 |
| 14 | 92.7 | 112.5 | 74.3 | 74.3 |
| 12 | 63.9 | 83.3 | 51.8 | 51.8 |
| 10 | 45 | 55.8 | 36.5 | 36.5 |
| 6 | 20.3 | 22.5 | 17.6 | 17.6 |
| 5 | 16.2 | 16.7 | 13.0 | 12.6 |
| 4 | 11.9 | 12.6 | 10.6 | 9.9 |
| 3½ | 9 | 9.5 | 7.7 | 7.7 |
| 3 | 8.1 | 7.2 | 5.9 | 5.9 |
| 2½ | 5.4 | 5.4 | 4.5 | 4.5 |
| 2 | 4.1 | 3.6 | 3.2 | 3.2 |
| 1½ | 3.2 | 3.2 | 2.9 | 2.7 |
| 1¼ | 2.3 | 2.7 | 2 | 1.8 |
| 1 | 1.8 | 1.8 | 1.4 | 1.4 |
| 3/4 | 1.4 | 1.4 | 1.4 | 1.4 |
| 1/2 | 0.9 | 0.9 | 0.9 | 1.4 |
| USA | Korea | Malaysia | Australia | Canada | Europe |
|---|---|---|---|---|---|
| ASME, ASTM, MSS SP44, AWWA, API-605 | KS | MS 816, MS 253 | AS 2129 | CSA B16.5/ B16.47 | EN |
| Russia | Japan | Europe | France | Germany | China |
| Ghost | JIS | ISO 7005, BS EN 1092-2 (Iron), PN | NF E 29-200/ NF E 29-203 | DIN | GB/T 9112 / 9119 |
| Italy | Europe | Europe | USA | Australia and UK | – |
| UNI 2276/ 6091 | BS EN 1092-1 (Steel) | BS EN 1092-3 (Alloy) | ANSI | BS 10 | – |
Types Of Class 300 Forged Flange
300 lb Blind Flange
300# Weld Neck Flange
ANSI 300 lb Long Weld Neck Flange
Class 300 Slip On Flange
ASME B16.5 Class 300 Socket Weld Flange
300# Threaded Flange
300 Lbs Lap Joint Flange
class 300 Orifice Flange
class 300 Spectacle Blind Flange
Class 300 RF Flange
Class 300 FF Flange
Class 300 RTJ Flange