Air/Vacuum Flow through an Orifice Table

Pressure Flow Through Orifices

Figures in body of chart are in air flows in SCFM (Standard cubic feet / minute)

Size Of Orifice (In.) Pressure (psig)
2 5 10 15 20 25 30 35 40 45 50 60 70 80 90 100 125 150 200
1/64″ .024 .040 .061 .079 .096 .113 .129 .145 .161 .177 .193 .225 .256 .287 .319 .350 .428 .506 .661
1/32″ .098 .161 .243 .319 .384 .451 .516 .581 .645 .709 .772 .898 1.02 1.15 1.27 1.40 1.71 2.02 2.64
3/64″ .22 .363 .547 .71 .86 1.01 1.16 1.31 1.45 1.59 1.74 2.02 2.30 2.59 2.87 3.15 3.85 4.55 5.95
1/16″ .391 .645 .972 1.26 1.54 1.80 2.07 2.32 2.58 2.84 3.09 3.59 4.10 4.60 5.10 5.60 6.85 8.09 10.6
3/32″ .881 1.45 2.19 2.84 3.46 4.06 4.65 5.23 5.81 6.38 6.95 8.09 9.22 10.3 11.5 12.6 15.4 18.2 23.8
1/8″ 1.57 2.58 3.89 5.05 6.15 7.21 8.26 9.30 10.3 11.3 12.4 14.4 16.4 18.4 20.4 22.4 27.4 32.4 42.3
3/16″ 3.52 5.80 8.75 11.4 13.8 16.2 18.6 20.9 23.2 25.5 27.8 32.3 36.9 41.4 45.9 50.4 61.6 72.8 95.2
1/4″ 6.26 10.3 15.6 20.2 24.6 28.9 33.0 37.2 41.3 45.4 49.4 57.5 65.5 73.6 81.6 89.6 110 129 169
3/8″ 14.1 23.2 35.0 45.4 55.3 64.9 74.4 83.7 92.9 102 111 129 147 166 184 202 246 291 381
1/2″ 25.1 41.3 62.2 80.8 98.4 115 132 149 165 181 198 230 262 294 326 358 438 518 677
5/8″ 39.1 64.5 97.2 126 154 180 207 232 258 284 309 359 410 460 510 560 685 809 1058
3/4″ 56.4 92.9 140 182 221 260 297 335 372 408 445 518 590 662 734 806 986 1165 1523
7/8″ 76.7 126 191 247 301 354 405 455 506 556 605 704 803 901 999 1097 1342 1586 2073
1″ 100 165 249 323 393 462 529 595 661 726 791 920 1049 1177 1305 1433 1752 2071
1-1/8″ 127 209 315 409 498 584 669 753 836 919 1001 1164 1327 1490 1652 1814 2218
1-1/4″ 157 258 389 505 615 721 826 930 1032 1134 1236 1438 1639 1839 2039 2239
1-3/8″ 189 312 471 611 744 893 1000 1125 1249 1372 1495 1739 1983 2226 2468
1-1/2″ 225 371 560 727 885 1039 1190 1339 1486 1633 1779 2070 2360
1-3/4″ 307 506 762 990 1205 1414 1619 1822 2023 2223 2422
2″ 401 660 996 1293 1574 1847 2115 2380

Vacuum Flow Through Orifices

Figures in body of chart are in air flows in SCFM (Standard cubic feet / minute)

Orifice Diameter (In)” Vacuum in inches of mercury
2″ 4″ 6″ 8″ 10″ 12″ 14″ 18″ 24″
1/64″ .018 .026 .032 .037 .041 .045 .048 .055 .063
1/32″ .074 .100 .128 .148 .165 .180 .195 .220 .250
1/16″ .300 .420 .517 .595 .660 .725 .780 .880 1.00
1/8″ 1.20 1.68 2.06 2.37 2.64 2.89 3.12 3.53 4.04
1/4″ 4.78 6.74 8.25 9.52 10.6 11.6 12.4 14.0 16.2
3/8″ 10.8 15.2 18.5 21.4 23.8 26.0 28.0 31.8 36.4
1/2″ 19.1 27.0 33.0 38.5 42.3 46.3 50.0 56.5 64.6
5/8″ 30.0 42.2 51.7 59.5 66.2 72.6 78.0 88.0 101
3/4″ 43.0 60.6 74.0 85.3 95.2 104 112 127 145
7/8″ 58.8 82.6 101 116 130 142 153 173 198
1″ 76.5 108 131 152 169 185 200 225 258