graph

1. Flow Rate, m°/s
A
S/uAo0jaN

2. 0.1
0.2
0.30.4
0.60.81
1.5
2
3
4
6
810
15
20
30
40
60
80
100
0.8
HH
0.6
0.6
0.5
Oiame
D
u
0.5
04
04
0.3
0.3
0.2
0.2
0.1
15
A
o.15
0.10
0.10
0.08
0.08
O.06
0.05
0.06
0.05
0.04
0.04
03
0.03
0.02
0.02
0.015
0.015
X
0.010
O.010
0.008
0.008
o.006
H
o.006
0.1
0.2
0.304
0.60.81
1.5
2
3
4
6810
15
20
30
40
60
80
100
Friction
Loss,
Pa/m-
Fig.
21.15
Duct
friction
chart:
low
flow
rates

3. Table 21.3 Circular equivalents of rectangular ducts for equal friction and flow rate
Side
Recta
ngular
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0
Duct
3.0 3.8 4.0 4.2 4.4 4.6 4.8 4.9 5.1 5.25.5 5.7 6.0 6.2 6.4 6.6 6.8 7.0
3.5
4.0
4.5
4.3 4.6 4.8 5.0 5.2 5.3 5.5 5.7 6.0 6.3 6.5 6.8 7.0 7.2
4.4 4.64.9 5.1 5.3 5.5 5.7 5.9 6.1 6.4 6.8 7.1 7.3 7.6 7.8 8.1 8.3
4.6 4.9 5.2 5.4 5.6 5.9 6.l 6.3 6.5 6.9 7.2 7.5 7.8 8.1 8.4 8.6 8.9
5.0 4.9 5.2 5.5 5.7 6.0 6.2 6.4 6.77 6.9 7.3 7.6 8.0 8.3 8.6 8.9 9.1 9.4
5.5 5.1 5.4 5.7 6.0 6.3 6.5 6.8 7.0 7.2 7.6 8.0 8.4 8.7 9.0 9.4 9.6 9.8
Side 9 10 11 12 13 1415 16 17 18 19 20 22 24 26 28 30 Side
Recta- Recta-
ngular ngular
Duct
Duct
6.6 6
7.1 7.7 7
7.4 8.2 8.8
8.0 8.6 9.3 9.9
8.4 9.1 9.8 10.4 10.9
9 9
10
1 8.8 9.5 10.2 10.8 11.4 12.0 11
12 9.1 9.9 10.7 11.3 11.9 12.5 13.1 12
3 9.5 10.3 11.1 11.8 12.4 13.0 13.6 14.2 13
9.8 10.7 11.5 12.2 12.9 13.5 14.2 14.7 15.3
10.1 11.0 11.8 12.6 13.3 14.0 14.6 15.3 15.8 16.4
14 4
5 15
6 10.4 11.4 12.2 13.0 13.7 14.4 15.1 15.7 16.3 16.9 17.5 6
I7 10.7 11.7 12.5 13.4 14.1 14.9 14.5 16.1 16.8 17.4 18.0 18.6 I7
18 11.0 11.9 12.9 13.7 14.5 15.3 16.0 16.6 17.3 17.9 18.5 19.1 19.7 I8
I9
11.2 12.2 13.2 14.1 14.9 15.6 16.4 17.1 17.8 18.4 19.0 19.6 20.2 20.8 19
(Contd)

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ap:s

5. 20 22 24 26 28 30 Side
13 14 15 16 17 18 19
7 8 9 10 11 12
Recta
Side
ngular
Duct
Recta-
ngular
39.6 41.8 43.8 45.9 47.8 49.7 72
74
Duct
72
40.0 42.3 44.4 46.4 48.4 50.3
74
40.5 42.8 44.9 47.0 49.0 50.8 766
40.9 43.3 45.5 47.5 49.5 51.5 78
80
76
18
41.3 43.8 46.0 48.0 50.1 52.0
32
80
41.8 44.2 46.4 48.6 50.6 52.6
34
32
42.2 44.6 46.9 49.2 51.1 53.2
36
34
42.6 45.0 47.4 49.6 51.6 53.7
38
36
43.0 45.4 47.9 50.1 52.2 54.3
90
38
43.4 45.9 48.3 50.6 52.8 54.8
90
43.8 46.3 48.7 51.1l 53.4 55.4 92
92
44.6 47.2 49.5 52.0 54.4 56.3 96
96
76 80 84 88 Side
60 64 68 72
46 48 50 52 56
Recta-
ngular
Duct
34 36 38 40 42 44
Side 32
Recta-
ngular
Duct
32
34
32 35.0
36
34 36.0 37.2
38
36 37.0 39.4
40
38 38.0 39.2 40.4 41.6
42
44
40 39.0 40.2 41.4 42.6 43.8
42 39.9 41.1 42.4 43.6 44.8 45.9
46
44 40.8 42.0 43.4 44.6 45.8 46.9 48.1
48
46 41.7 43.0 44.3 45.6 46.8 47.9 49.1 50.3
48 42.6 43.9 45.2 46.5 47.8 48.9 50.2 51.3 52.6

6. 80 84 88 Side
32 34 36 38 40 42 44 46 48 50 52 56 60 64 68 72 76
Recta-
ngular
Duct
Side
Recta
ngular
Duct
50
50 43.5 44.8 46.1 47.4 48.8 49.8 51.2 52.3 53.6 54.7
52
44.3 45.7 47.1 48.3 49.7 50.8 52.2 53.3 54.6 55.8 56.9
54
D2
4 45.0 46.5 48.0 49.2 50.6 51.8 53.2 54.3 55.6 56.8 57.9
56
45.8 47.3 48.8 50.1 51.5 52.7 54.1 55.3 56.5 57.8 58.9 61.3
58
6
46.6 48.1 49.6 51.0 52.4 53.7 55.0 56.2 57.5 58.8 60.0 62.3
60
S8
47.3 48.9 50.4 51.8 53.3 54.6 55.9 57.1 58.5 59.8 61.0 63.3 65.7
62
60
48.0 49.7 51.2 52.6 54.2 55.5 56.8 58.0 59.4 60.7 62.0 64.3 66.7
64
52
48.7 50.4 52.0 53.4 55.0 56.4 57.7 59.0 60.3 61.6 62.9 65.3 67.7 70.0
66
b4
49.5 51.1 52.8 54.2 55.8 57.2 58.6 59.9 61.2 62.5 63.9 66.3 68.7 71.1
68
66
50.2 51.8 53.5 55.0 56.6 58.0 59.5 60.8 62.1 63.4 64.8 67.3 69.7 72.1 74.4
0
68
50.9 52.5 54.2 55.8 57.3 58.8 60.3 61.7 63.0 64.3 65.7 68.3 70.7 73.1 75.4
72
0
51.5 53.2 54.9 56.5 58.0 59.6 61.1 62.6 63.9 65.2 66.6 69.2 71.7 74.1 76.4 78.8
74
72
74 52.1 53.9 55.6 57.2 58.8 60.4 61.9 63.3 64.8 66.1 67. 70.1 72.7 75.1 77.4 79.9 83.2
6
52.7 54.6 56.3 57.9 59.5 61.2 62.7 64.1 65.6 67.0 68.4 71.0 73.6 76.1 78.4 80.9 84.2
78
76
53.3 55.2 57.0 58.6 60.362.0 63.4 64.9 66.4 67.9 69.3 71.8 74.5 77.1 79.4 81.8 84.2
30
78
53.9 55.8 57.6 59.3 61.0 62.7 64.1 65.7 67.2 68.7 70.1 72.7 75.4 78.1 80.4 82.6 85.2 87.5
82
80
54.5 56.4 58.2 60.0 61.7 63.4 64.9 66.5 68.0 69.5 71.0 73.6 76.3 79.0 81.4 83.8 86.2 88.6
34
82
84 55.1 57.0 58.9 60.7 62.4 64.1 65.7 67.3 68.8 70.3 71.3 74.5 77.2 79.9 82.4 84.8 87.2 89.6 91.9
86
86 55.7 57.6 59.5 61.3 63.0 64.8 66.4 68.0 69.5 71.1 72.6 75.4 78.1 80.8 83.3 85.8 88.2 90.6 92.9
88
88 S6.3 58.2 60.1 62.0 63.7 65.4 67.0 68.7 70.3 71.8 73.4 76.3 79.0 81.6 84.2 86.8 89.2 91.6 93.9 96.3
90
90 56.9 58.8 60.7 62.6 64.4 66.0 67.8 69.4 71.1 72.6 74.2 77.1 79.9 82.5 85.1 87.8 90.2 92.6 94.9 97.3
92 57.4 59.4 61.3 63.2 65.0 66.8 68.5 70.1 71.8 73.3 74.9 77.9 80.8 83.4 86.0 88.7 91.2 93.6 95.9 98.3 92
94 57.9 60.0 61.9 63.8 65.6 67.5 69.2 70.8 72.5 74.1 75.6 78.7 81.7 84.3 86.9 89.6 92.1 94.6 96.9 99.3 94
96 58.4 60.5 62.4 64.4 66.2 68.2 69.8 71.5 73.2 74.3 76.3 79.4 82.6 85.2 87.8 90.5 93.0 95.6 97.9 100.3 96