Related Resources: fluid flow

Flow of Air in Pipes Equation and Calculator

Hydraulic & Pneumatics
Fluids Design and Engineering Data

Flow of Air in Pipes Equation and Calculator

Flow of Air in Pipes Equation and Calculator

where:

v = velocity of air in feet per second (ft/sec)
p = loss of pressure due to flow through the pipes in ounces per square inch (ounces/in2)
d = inside diameter of pipe in inches (in)
L = length of pipe in feet (ft)

The horsepower required to drive air through a pipe equals the volume of air in cubic feet per second multiplied by the pressure in pounds per square foot, and this product divided by 550.

Velocity
of Air
Ft/sec
Actual Inside
Diameter of Pipe, Inches
1
2
3
4
6
8
10
12
16
24
1
2
3
4
5
6
7
8
9
10
12
15
18
20
24
25
28
30
0.33
0.65
0.98
1.31
1.64
1.96
2.29
2.62
2.95
3.27
3.93
4.91
5.89
6.55
7.86
8.18
9.16
9.80
1.31
2.62
3.93
5.24
6.55
7.85
9.16
10.50
11.78
13.1
15.7
19.6
23.5
26.2
31.4
32.7
36.6
39.3
2.95
5.89
8.84
11.78
14.7
17.7
20.6
23.5
26.5
29.4
35.3
44.2
53.0
59.0
71.0
73.0
82.0
88.0
5.2
10.5
15.7
20.9
26.2
31.4
36.6
41.9
47.0
52.0
63.0
78.0
94.0
105.0
125.0
131.0
146.0
157.0
11.8
23.6
35.3
47.1
59.0
70.7
82.4
94.0
106.0
118.0
141.0
177.0
212.0
235.0
283.0
294.0
330.0
353.0
20.9
41.9
62.8
83.8
104.0
125.0
146.0
167.0
188.0
209.0
251.0
314.0
377.0
419.0
502.0
523.0
586.0
628.0
32.7
65.4
98.2
131.0
163.0
196.0
229.0
262.0
294.0
327.0
393.0
491.0
589.0
654.0
785.0
818.0
916.0
982.0
47.1
94.2
141.4
188.0
235.0
283.0
330.0
377.0
424.0
471.0
565.0
707.0
848.0
942.0
1131.0
1178.0
1319.0
1414.0
83.8
167.5
251.3
335.0
419.0
502.0
586.0
670.0
754.0
838.0
1005.0
1256.0
1508.0
1675.0
2010.0
2094.0
2346.0
2513.0
188
377
565
754
942
1131
1319
1508
1696
1885
2262
2827
3393
3770
4524
4712
5278
5655