Sizing Circular Ducts
A rough guide to maximum air volume capacity of circular ducts in comfort, industrial and high speed ventilation systems.
Maximum air velocity in the ducts should be kept below certain limits to avoid unacceptable noise generation.
The values from the table below can be used for rough sizing of ducts in comfort, industrial and high speed ventilation systems.
For full table with Industrial and High Speed Systems - rotate the screen!
Maximum Air Volume Flow (m3/h) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Diameter (mm) | Area (m2) | Comfort systems | Industrial systems | High speed systems | ||||||
Main ducts | Secondary ducts | Connecting ducts | Main ducts | Secondary ducts | Connecting ducts | Main ducts | Secondary ducts | Connecting ducts | ||
Speed (m/s) | ||||||||||
5.5 | 4 | 2 | 10 | 6.5 | 4 | 14 | 9 | 6.5 | ||
63 | 0.003 | 62 | 45 | 22 | 112 | 73 | 45 | 157 | 101 | 73 |
80 | 0.005 | 99 | 72 | 36 | 181 | 118 | 72 | 253 | 163 | 118 |
100 | 0.008 | 155 | 113 | 57 | 283 | 184 | 113 | 396 | 254 | 184 |
125 | 0.012 | 243 | 177 | 88 | 442 | 287 | 177 | 618 | 397 | 287 |
160 | 0.020 | 398 | 289 | 145 | 723 | 470 | 289 | 1013 | 651 | 470 |
200 | 0.031 | 622 | 452 | 226 | 1130 | 735 | 452 | 1583 | 1017 | 735 |
250 | 0.049 | 971 | 707 | 353 | 1766 | 1148 | 707 | 2473 | 1590 | 1148 |
315 | 0.078 | 1542 | 1122 | 561 | 2804 | 1823 | 1122 | 3926 | 2524 | 1823 |
400 | 0.126 | 2487 | 1809 | 904 | 4522 | 2939 | 1809 | 6330 | 4069 | 2939 |
500 | 0.196 | 3886 | 2826 | 1413 | 7065 | 4592 | 2826 | 9891 | 6359 | 4592 |
630 | 0.312 | 6169 | 4487 | 2243 | 11216 | 7291 | 4487 | 15703 | 10095 | 7291 |
800 | 0.502 | 9948 | 7235 | 3617 | 18086 | 11756 | 7235 | 25321 | 16278 | 11756 |
1000 | 0.785 | 15543 | 11304 | 5652 | 28260 | 18369 | 11304 | 39564 | 25434 | 18369 |
1250 | 1.227 | 24286 | 17663 | 8831 | 44156 | 28702 | 17663 | 61819 | 39741 | 28702 |