Kalp Alloys is a leading manufacturer and supplier of Class 150 Flanges (also known as 150 lb flanges or 150# flanges) conforming to ASME B16.5 standard. We supply Class 150 pipe flanges in all standard types — Slip-On (SOF), Welding Neck (WNF), Socket Welding (SWF), Threaded (THDF), Lap Joint (LJF), and Blind (BLF) — in sizes ranging from NPS 1/2″ to NPS 24″. Our flanges are manufactured in a wide range of materials including Stainless Steel (SS 304, 316L, 321), Carbon Steel, Alloy Steel, Duplex, and Nickel Alloys to meet the most demanding industrial requirements.
A Class 150 flange is a pressure-class designation under the ASME B16.5 standard (Steel Pipe Flanges and Flanged Fittings). The “150” refers to the pressure class — the lowest and most commonly used class in industrial piping. Class 150 flanges are rated at approximately 285 psi (19.6 bar) at ambient temperature (38°C) for carbon steel.
They are widely used in oil & gas, chemical, petrochemical, water treatment, pharmaceutical, and general industrial piping systems where low-to-medium pressures are encountered. Because of their versatility and cost-effectiveness, ASME B16.5 Class 150 flanges are one of the most demanded flange types globally.
| NPS | Outside Diam. D | Diam. of Hub X | OD of RF G | Thickness (Min) | Bore | Length Thru Hub | Depth of Socket Y | Drilling | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| WNF SWF B1 | SOF SWF (Min) | LJF (Min) | WNF T1 | SOF THDF SWF | LJF T3 | BCD C | Number of Bolt Holes N | Diam. of Bolt Holes (*) H | |||||||
| B2 | B3 | T2 | |||||||||||||
| t | t1 | ||||||||||||||
| 1/2 | 90 | 30 | 34.9 | 9.6 | 11.2 | See Note (1) To be specified by Purchaser | 22.2 | 22.9 | 46 | 14 | 14 | 10 | 60.3 | 4 | 15.9 |
| 3/4 | 100 | 38 | 42.9 | 11.2 | 12.7 | 27.7 | 28.2 | 51 | 14 | 14 | 11 | 69.9 | 4 | 15.9 | |
| 1 | 110 | 49 | 50.8 | 12.7 | 14.3 | 34.5 | 34.9 | 54 | 16 | 15 | 13 | 79.4 | 4 | 15.9 | |
| 1 1/4 | 115 | 59 | 63.5 | 14.3 | 15.9 | 43.2 | 43.7 | 56 | 19 | 19 | 14 | 88.9 | 4 | 15.9 | |
| 1 1/2 | 125 | 65 | 73.0 | 15.9 | 17.5 | 49.5 | 50.0 | 60 | 21 | 20 | 16 | 98.4 | 4 | 15.9 | |
| 2 | 150 | 78 | 92.1 | 17.5 | 19.1 | 61.9 | 62.5 | 62 | 24 | 23 | 17 | 120.7 | 4 | 19.1 | |
| 2 1/2 | 180 | 90 | 104.8 | 20.7 | 22.3 | 74.6 | 75.4 | 68 | 27 | 27 | 19 | 139.7 | 4 | 19.1 | |
| 3 | 190 | 108 | 127.0 | 22.3 | 23.9 | 90.7 | 91.4 | 68 | 29 | 28 | 21 | 152.4 | 4 | 19.1 | |
| 3 1/2 | 215 | 122 | 139.7 | 22.3 | 23.9 | 103.4 | 104.1 | 70 | 30 | 30 | – | 177.8 | 8 | 19.1 | |
| 4 | 230 | 135 | 157.2 | 22.3 | 23.9 | 116.1 | 116.8 | 75 | 32 | 31 | – | 190.5 | 8 | 19.1 | |
| 5 | 255 | 164 | 185.7 | 22.3 | 23.9 | 143.8 | 144.4 | 87 | 35 | 34 | – | 215.9 | 8 | 22.2 | |
| 6 | 280 | 192 | 215.9 | 23.9 | 25.4 | 170.7 | 171.4 | 87 | 38 | 38 | – | 241.3 | 8 | 22.2 | |
| 8 | 345 | 246 | 269.9 | 27.0 | 28.6 | 221.5 | 222.2 | 100 | 43 | 42 | – | 298.5 | 8 | 22.2 | |
| 10 | 405 | 305 | 323.8 | 28.6 | 30.2 | 276.2 | 277.4 | 100 | 48 | 47 | – | 362.0 | 12 | 25.4 | |
| 12 | 485 | 365 | 381.0 | 30.2 | 31.8 | 327.0 | 328.2 | 113 | 54 | 54 | – | 431.8 | 12 | 25.4 | |
| 14 | 535 | 400 | 412.8 | 33.4 | 35.0 | 359.2 | 360.2 | 125 | 56 | 77 | – | 476.3 | 12 | 28.6 | |
| 16 | 595 | 457 | 469.9 | 35.0 | 36.6 | 410.5 | 411.2 | 125 | 62 | 85 | – | 539.8 | 16 | 28.6 | |
| 18 | 635 | 505 | 533.4 | 38.1 | 39.7 | 461.8 | 462.3 | 138 | 67 | 95 | – | 577.9 | 16 | 31.8 | |
| 20 | 700 | 559 | 584.2 | 41.3 | 42.9 | 513.1 | 514.4 | 143 | 71 | 102 | – | 635.0 | 20 | 31.8 | |
| 24 | 815 | 663 | 692.2 | 46.1 | 47.7 | 616.0 | 616.0 | 151 | 81 | 109 | – | 749.3 | 20 | 34.9 | |
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