API Pressure Rating Flange Ring Groove Bolt Studs
Nominal Size Outside Diameter T P E Width Ring No D Bolt Circle No. Size Stud Length
in mm in mm in mm in mm in mm in mm in mm
2000 psi 13.8 MPa (R or RX Gasket) 21/16 52.4 61/2 165 15/16 33.3 31/4 82.55 15/32 11.91 23 5 127.0 8 5/8 41/2 108
29/16 65.1 71/2 191 17/16 36.5 4 101.60 15/32 11.91 26 57/8 149.2 8 3/4 5 127
31/8 79.4 81/4 210 19/16 39.7 47/8 123.83 15/32 11.91 31 65/8 168.3 8 3/4 51/4 133
41/16 103.2 103/4 273 113/16 46.0 57/8 149.23 15/32 11.91 37 81/2 215.9 8 7/8 6 152
51/8 130.0 13 330 21/16 52.4 71/8 180.98 15/32 11.91 41 101/2 266.7 8 1 63/4 165
71/16 179.4 14 356 23/16 55.6 85/16 211.14 15/32 11.91 45 111/2 292.1 12 1 7 178
9 228.6 161/2 419 21/2 63.5 105/8 269.88 15/32 11.91 49 133/4 349.3 12 11/8 8 203
11 279.4 20 508 213/16 71.4 123/4 323.85 15/32 11.91 53 17 431.8 16 11/4 83/4 222
135/8 346.1 22 559 215/16 74.6 15 381.00 15/32 11.91 57 191/4 489.0 20 11/4 9 229
163/4 425.5 27 686 35/16 84.1 181/2 469.90 15/32 11.91 65 233/4 603.3 20 11/2 101/4 260
211/4 539.8 32 813 37/8 98.4 23 584.20 17/32 13.49 73 281/2 723.9 24 15/8 113/4 298
3000 psi 20.7 MPa (R or RX Gasket) 21/16 52.4 81/2 216 113/16 46.0 33/4 95.25 15/32 11.91 24 61/2 165.1 8 7/8 6 152
29/16 65.1 95/8 244 115/16 49.2 41/4 107.95 15/32 11.91 27 71/2 190.5 8 1 61/2 165
31/8 79.4 91/2 241 113/16 46.0 47/8 123.83 15/32 11.91 31 71/2 190.5 8 7/8 6 152
41/16 103.2 111/2 292 21/16 52.4 57/8 149.23 15/32 11.91 37 91/4 235.0 8 11/8 7 178
51/8 130.0 133/4 350 25/16 58.8 71/8 180.98 15/32 11.91 41 11 279.4 8 11/4 73/4 195
71/16 179.4 15 381 21/2 63.5 85/16 211.14 15/32 11.91 45 121/2 317.5 12 11/8 8 203
9 228.6 181/2 470 213/16 71.4 105/8 269.88 15/32 11.91 49 151/2 393.7 12 13/8 9 229
11 279.4 211/2 546 31/16 77.8 123/4 323.85 15/32 11.91 53 181/2 469.9 16 13/8 91/2 241
135/8 346.1 24 610 37/16 87.3 15 381.00 15/32 11.91 57 21 533.4 20 13/8 101/4 260
163/4 425.5 273/4 705 315/16 100.0 181/2 469.90 21/32 16.67 66 241/4 616.0 20 15/8 113/4 298
203/4 527.1 333/4 857 43/4 120.7 23 584.20 25/32 19.84 74 291/2 749.3 20 2 141/2 368
5000 psi 34.5 MPa (R or RX Gasket) 21/16 52.4 81/2 216 113/16 46.0 33/4 95.25 15/32 11.91 24 61/2 165.1 8 7/8 6 152
29/16 65.1 95/8 244 115/16 49.2 41/4 107.95 15/32 11.91 27 71/2 190.5 8 1 61/2 165
31/8 79.4 101/2 267 23/16 55.6 53/8 136.53 15/32 11.91 35 8 203.2 8 11/8 71/4 184
41/16 103.2 121/4 311 27/16 61.9 63/8 161.93 15/32 11.91 39 91/2 241.3 8 11/4 8 203
51/8 130.0 143/4 375 33/16 81.0 75/8 193.68 15/32 11.91 44 111/2 292.1 8 11/2 10 255
71/16 179.4 151/2 394 35/8 92.1 85/16 211.14 17/32 13.49 46 121/2 317.5 12 13/8 103/4 273
9 228.6 19 483 41/16 103.2 105/8 269.88 21/32 16.67 50 151/2 393.7 12 15/8 12 305
11 279.4 23 584 411/16 119.1 123/4 323.85 21/32 16.67 54 19 482.6 12 17/8 133/4 349
API Pressure Rating Flange Ring Groove Bolt Studs
Nominal Size Outside Diameter T P E Width Ring No D Bolt Circle No. Size Stud Length
in mm in mm in mm in mm in mm in mm in mm
5000 psi 34.5 MPa (BX Gasket) 135/8 346.1 261/2 673 47/16 112.7 16.063 408.00 0.786 19.96 BX-160 231/4 590.6 16 15/8 121/2 318
163/4 425.5 303/8 772 51/8 130.2 18.832 478.33 0.705 17.91 BX-162 265/8 676.3 16 17/8 141/2 368
183/4 476.3 355/8 905 617/32 165.9 22.185 563.50 1.006 25.55 BX-163 315/8 803.3 20 2 171/2 445
211/4 539.8 39 991 71/8 181.0 24.904 632.56 1.071 27.20 BX-165 347/8 885.8 24 2 183/4 476
10,000 psi 69.0 MPa (BX Gasket) 113/16 46.0 73/8 187 121/32 42.1 3.062 77.77 0.466 11.84 BX-151 53/4 146.1 8 3/4 5 127
21/16 52.4 77/8 200 147/64 44.1 3.395 86.23 0.498 12.65 BX-152 61/4 158.8 8 3/4 51/4 133
29/16 65.1 91/8 232 21/64 51.2 4.046 102.77 0.554 14.07 BX-153 71/4 184.2 8 7/8 6 152
31/16 77.8 105/8 270 219/64 58.3 4.685 119.00 0.606 15.39 BX-154 81/2 215.9 8 1 63/4 171
41/16 103.2 127/16 316 249/64 70.2 5.930 150.62 0.698 17.73 BX-155 103/16 258.8 8 11/8 8 203
51/8 130.2 141/16 357 31/8 79.4 6.955 176.66 0.666 16.92 BX-169 1113/16 300.0 12 11/8 83/4 222
71/16 179.4 187/8 479 41/16 103.2 9.521 241.83 0.921 23.39 BX-156 157/8 403.2 12 11/2 111/4 286
9 228.6 213/4 552 47/8 123.8 11.774 299.06 1.039 26.39 BX-157 183/4 476.3 16 11/2 13 330
11 279.4 253/4 654 59/16 141.3 14.064 357.23 1.149 29.18 BX-158 221/4 565.2 16 13/4 15 381
135/8 346.1 301/4 768 65/8 168.3 17.033 432.64 1.279 32.49 BX-159 261/2 673.1 20 17/8 171/4 438
163/4 425.5 345/16 872 65/8 168.3 18.832 478.33 0.705 17.91 BX-162 309/16 776.3 24 17/8 171/2 445
183/4 476.3 4015/16 1040 825/32 223.0 22.752 577.90 1.290 32.77 BX-164 367/16 925.5 24 21/4 221/2 572
211/4 539.8 45 1143 91/2 241.3 25.507 647.88 1.373 34.87 BX-166 401/4 1022.4 24 21/2 241/2 622
15,000 psi 103.5 MPa (BX Gasket) 113/16 46.0 83/16 208 125/32 45.2 3.062 77.77 0.466 11.84 BX-151 65/16 160.3 8 7/8 51/2 140
21/16 52.4 83/4 222 2 50.8 3.395 86.23 0.498 12.65 BX-152 67/8 174.6 8 7/8 6 152
29/16 65.1 10 254 21/4 57.2 4.046 102.77 0.554 14.07 BX-153 77/8 200.0 8 1 63/4 171
31/16 77.8 115/16 287 217/32 64.3 4.685 119.00 0.606 15.39 BX-154 91/16 230.2 8 11/8 71/2 191
41/16 103.2 143/16 360 33/32 78.6 5.930 150.62 0.698 17.73 BX-155 117/16 290.5 8 13/8 91/4 235
71/16 179.4 197/8 505 411/16 119.1 9.521 241.83 0.921 23.39 BX-156 167/8 428.6 16 11/2 123/4 324
9 228.6 251/2 648 53/4 146.1 11.774 299.06 1.039 26.39 BX-157 213/4 552.5 16 17/8 153/4 400
11 279.4 32 813 73/8 187.3 14.064 357.23 1.149 29.18 BX-158 28 711.2 20 2 191/4 489
135/8 346.1 347/8 886 81/16 204.8 17.033 432.60 1.279 32.50 BX-159 307/8 784.2 20 21/4 211/4 540
183/4 476.3 453/4 1162 101/16 255.6 22.752 577.90 1.290 32.77 BX-164 4 1016.0 20 3 263/4 679
20,000 psi 138.0 MPa (BX Gasket) 113/16 46.0 101/8 257 21/2 63.5 3.062 77.77 0.466 11.84 BX-151 8 203.2 8 1 71/2 191
21/16 52.4 115/16 287 213/16 71.4 3.395 86.23 0.498 12.65 BX-152 91/16 230.2 8 11/8 81/4 210
29/16 65.1 1213/16 325 31/8 79.4 4.046 102.77 0.554 14.07 BX-153 105/16 261.9 8 11/4 91/4 235
31/16 77.8 141/16 357 33/8 85.7 4.685 119.00 0.606 15.39 BX-154 115/16 287.3 8 13/8 10 254
41/16 103.2 179/16 446 43/16 106.4 5.930 150.62 0.698 17.73 BX-155 141/6 357.2 8 13/4 121/4 311
71/16 179.4 2513/16 656 61/2 165.1 9.521 241.83 0.921 23.39 BX-156 2113/16 554.0 16 2 171/2 445
9 228.6 3111/16 805 81/16 204.8 11.774 399.06 1.039 26.39 BX-157 27 685.8 16 21/2 223/8 568
11 279.4 343/4 883 813/16 223.8 14.064 357.23 1.149 29.18 BX-158 291/2 749.3 16 23/4 233/4 603
135/8 346.1 353/4 1162 111/2 292.1 17.033 432.64 1.279 32.49 BX-159 40 1016.0 20 31/8 30 762