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Velocity in Schedule 80 Plastic Pipe for Water - Safe Flow Velocity
Hayward establishes a generally accepted safe flow velocity for plastic piping systems. For systems without fast opening or closing valves, a maximum velocity of 8 feet per second is recommended. However, for systems equipped with such valves (like solenoid or pneumatically actuated valves lacking speed controls), the maximum velocity is typically limited to 5 feet per second. In contrast, metal piping systems are often designed to accommodate flow rates of up to 15 feet per second, significantly higher than those acceptable for plastic systems. This distinction is crucial when considering the installation of plastic components such as valves, strainers, or filters within a metal system.
| Discharge | Velocity in Schedule 80 Plastic Pipe for Water @ 15.5°C (60°F) | ||||||||||
| Lt/Hour | Lt/Min | GPM (US) | Cubic Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec | Feet / Sec |
| 1/4" | 3/8" | 1/2" | 3/4" | 1" | 1-1/4" | 1-1/2" | |||||
| 45 | 0.8 | 0.2 | 0.000446 | — | 0.824 | — | — | — | — | — | — |
| 68 | 1.1 | 0.3 | 0.000668 | — | 1.237 | 0.651 | 0.392 | — | — | — | — |
| 91 | 1.5 | 0.4 | 0.000891 | — | 1.646 | 0.867 | 0.529 | — | — | — | — |
| 114 | 1.9 | 0.5 | 0.00111 | — | 2.061 | 1.083 | 0.653 | 0.359 | — | — | — |
| 136 | 2.3 | 0.6 | 0.00134 | — | 2.476 | 1.303 | 0.782 | 0.431 | — | — | — |
| 182 | 3.0 | 0.8 | 0.00178 | — | 3.295 | 1.728 | 1.043 | 0.574 | — | — | — |
| 227 | 3.8 | 1 | 0.00223 | — | 4.122 | 2.167 | 1.311 | 0.718 | 0.435 | — | — |
| 454 | 7.6 | 2 | 0.00446 | — | 8.245 | 4.335 | 2.609 | 1.432 | 0.871 | 0.525 | — |
| 681 | 11.4 | 3 | 0.00668 | — | 12.38 | 6.502 | 3.919 | 2.161 | 1.306 | 0.788 | 0.538 |
| 908 | 15.1 | 4 | 0.00891 | 2" | 16.50 | 8.67 | 5.218 | 2.876 | 1.747 | 1.051 | 0.717 |
| 1136 | 18.9 | 5 | 0.01114 | — | — | 10.837 | 6.528 | 3.592 | 2.181 | 1.313 | 0.896 |
| 1363 | 22.7 | 6 | 0.01337 | 0.65 | 2-1/2" | 13.01 | 7.827 | 4.308 | 2.614 | 1.579 | 1.076 |
| 1817 | 30.3 | 8 | 0.01782 | 0.86 | — | — | 10.448 | 5.741 | 3.482 | 2.105 | 1.434 |
| 2271 | 37.9 | 10 | 0.02228 | 1.08 | 0.752 | 3" | 13.057 | 7.185 | 4.351 | 2.632 | 1.798 |
| 3407 | 56.8 | 15 | 0.03342 | 1.61 | 1.134 | — | — | 10.778 | 6.531 | 3.941 | 2.697 |
| 4542 | 75.7 | 20 | 0.04456 | 2.15 | 1.505 | 0.986 | — | — | 8.712 | 5.252 | 3.596 |
| 5678 | 94.6 | 25 | 0.0557 | 2.69 | 1.886 | 1.238 | — | 4" | 10.881 | 6.574 | 4.484 |
| 6814 | 113.6 | 30 | 0.06684 | 3.23 | 2.256 | 1.476 | — | — | 13.062 | 7.884 | 5.383 |
| 7949 | 132.5 | 35 | 0.07798 | 3.78 | 2.638 | 1.726 | — | 0.973 | 15.232 | 9.193 | 6.282 |
| 9085 | 151.4 | 40 | 0.08912 | 4.32 | 3.009 | 1.976 | — | 1.114 | 17.413 | 10.515 | 7.171 |
| 10221 | 170.3 | 45 | 0.1003 | 4.84 | 3.391 | 2.215 | — | 1.247 | — | 11.838 | 8.069 |
| 11356 | 189.3 | 50 | 0.1114 | 5.39 | 3.761 | 2.465 | — | 1.391 | — | 13.147 | 8.969 |
| 13627 | 227.1 | 60 | 0.1337 | 6.47 | 4.513 | 2.953 | — | 1.665 | — | 15.779 | 10.778 |
| 15899 | 265.0 | 70 | 0.156 | 7.55 | 5.266 | 3.453 | — | 1.942 | — | — | 12.577 |
| 18170 | 302.8 | 80 | 0.1782 | 8.62 | 6.018 | 3.942 | — | 2.228 | — | 6" | 14.360 |
| 20441 | 340.7 | 90 | 0.2005 | 9.69 | 6.771 | 4.442 | — | 2.504 | — | — | 16.162 |
| 22712 | 378.5 | 100 | 0.2228 | 10.77 | 7.523 | 4.931 | — | 2.781 | — | 1.225 | 17.960 |
| 28391 | 473.2 | 125 | 0.2785 | 13.48 | 9.409 | 6.168 | — | 3.475 | — | 1.534 | 22.445 |
| 34069 | 567.8 | 150 | 0.3342 | 16.18 | 11.28 | 7.395 | — | 4.171 | — | 1.893 | — |
| 39747 | 662.4 | 175 | 0.3899 | 18.87 | 13.17 | 8.63 | — | 4.865 | — | 2.141 | 8" |
| 45425 | 757.1 | 200 | 0.4456 | 21.56 | 15.07 | 9.86 | — | 5.561 | — | 2.451 | — |
| 51103 | 851.7 | 225 | 0.5013 | — | 16.94 | 11.10 | — | 6.255 | — | 2.759 | 1.577 |
| 56781 | 946.4 | 250 | 0.557 | — | — | 12.325 | — | 6.951 | — | 3.069 | 1.752 |
| 62459 | 1041.0 | 275 | 0.6127 | — | — | 13.563 | — | 7.645 | — | 3.367 | 1.927 |
| 68137 | 1135.6 | 300 | 0.6684 | — | — | 14.768 | — | 8.341 | — | 3.675 | 2.102 |
| 73815 | 1230.3 | 325 | 0.7241 | — | — | 16.041 | — | 9.035 | — | 3.985 | 2.277 |
| 79494 | 1324.9 | 350 | 0.7798 | — | — | — | — | 9.731 | — | 4.294 | 2.453 |
| 85172 | 1419.5 | 375 | 0.8355 | — | — | — | — | 10.425 | — | 4.592 | 2.628 |
| 90850 | 1514.2 | 400 | 0.8912 | — | — | — | — | 11.121 | — | 4.901 | 2.803 |
| 96528 | 1608.8 | 425 | 0.9469 | 10" | — | — | — | 11.815 | — | 5.211 | 2.989 |
| 102206 | 1703.4 | 450 | 1.003 | — | — | — | — | 12.511 | — | 5.519 | 3.164 |
| 107884 | 1798.1 | 475 | 1.059 | 2.199 | — | — | — | 13.205 | — | 5.817 | 3.329 |
| 113562 | 1892.7 | 500 | 1.114 | 2.229 | — | — | — | 13.901 | — | 6.126 | 3.515 |
| 124919 | 2082.0 | 550 | 1.225 | 2.459 | — | — | — | 15.279 | — | 6.744 | 3.865 |
| 136275 | 2271.2 | 600 | 1.337 | 2.679 | 12" | — | — | 16.681 | — | 7.352 | 4.215 |
| 147631 | 2460.5 | 650 | 1.225 | 2.899 | — | — | — | — | — | 7.971 | 4.566 |
| 158987 | 2649.8 | 700 | 1.56 | 3.129 | 2.205 | — | — | — | — | 8.588 | 4.916 |
| 170343 | 2839.1 | 750 | 1.671 | 3.349 | 2.359 | — | — | — | — | 9.195 | 5.267 |
| 181700 | 3028.3 | 800 | 1.56 | 3.569 | 2.513 | — | — | — | — | 9.802 | 5.617 |
| 193056 | 3217.6 | 850 | 1.782 | 3.799 | 2.677 | — | — | — | — | 10.421 | 5.968 |
| 204412 | 3406.9 | 900 | 2.005 | 4.019 | 2.831 | — | — | — | — | 11.028 | 6.318 |
| 215768 | 3596.1 | 950 | 2.117 | 4.239 | 2.984 | — | — | — | — | 11.646 | 6.668 |
| 227125 | 3785.4 | 1000 | 2.228 | 4.469 | 3.149 | — | — | — | — | 12.253 | 7.019 |
| 249837 | 4164.0 | 1100 | 2.451 | 4.919 | 3.458 | — | — | — | — | 13.489 | 7.719 |
| 272550 | 4542.5 | 1200 | 2.674 | 5.359 | 3.775 | — | — | — | — | 14.715 | 8.431 |
| 295262 | 4921.0 | 1300 | 2.896 | 5.809 | 4.093 | — | — | — | — | 15.929 | 9.121 |
| 317974 | 5299.6 | 1400 | 3.119 | 6.259 | 4.401 | — | — | — | — | 17.165 | 9.833 |
| 340687 | 5678.1 | 1500 | 3.342 | 6.698 | 4.718 | — | — | — | — | 18.391 | 10.534 |
| 363399 | 6056.7 | 1600 | 3.565 | 7.148 | 5.037 | — | — | — | — | 19.611 | 11.235 |
| 408824 | 6813.7 | 1800 | 4.01 | 8.038 | 5.662 | — | — | — | — | 22.067 | 12.636 |
| 454249 | 7570.8 | 2000 | 4.456 | 8.938 | 6.228 | — | — | — | — | 24.517 | 14.038 |
| 567812 | 9463.5 | 2500 | 5.57 | 11.168 | 7.868 | — | — | — | — | — | 17.552 |
| 681374 | 11356.2 | 3000 | 6.684 | 13.396 | 9.437 | — | — | — | — | — | 21.068 |
| 794936 | 13248.9 | 3500 | 7.798 | 15.637 | 11.006 | — | — | — | — | — | 24.572 |
| 908498 | 15141.6 | 4000 | 8.912 | 17.866 | 12.587 | — | — | — | — | — | 28.080 |
| 1022061 | 17034.3 | 4500 | 10.13 | 20.106 | 14.156 | — | — | — | — | — | 31.613 |
| 1135623 | 18927.1 | 5000 | 11.14 | — | — | — | — | — | — | — | |
| 1362748 | 22712.5 | 6000 | 13.37 | — | — | — | — | — | — | — | — |
| 1589872 | 26497.9 | 7000 | 15.6 | — | — | — | — | — | — | — | — |
| 1816997 | 30283.3 | 8000 | 17.82 | — | — | — | — | — | — | — | — |
| 2044121 | 34068.7 | 9000 | 20.05 | — | — | — | — | — | — | — | — |
| 2271246 | 37854.1 | 10000 | 22.28 | — | — | — | — | — | — | — | — |
| 2725495 | 45424.9 | 12000 | 26.74 | — | — | — | — | — | — | — | — |
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