Duct fitting pressure drop coefficients for
round elbows with three, four, and five pieces
From ASHRAE (1989), with permission
The pressure drop coefficient is given by C = Kq · C90
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Number of pieces |
r/D |
|||
0.75 |
1.0 |
1.5 |
2.0 |
|
5 |
0.46 |
0.33 |
0.24 |
0.19 |
4 |
0.50 |
0.37 |
0.27 |
0.24 |
3 |
0.54 |
0.42 |
0.34 |
0.33 |
q |
0 |
20 |
30 |
45 |
60 |
75 |
90 |
110 |
130 |
150 |
180 |
K q |
0 |
0.31 |
0.45 |
0.60 |
0.78 |
0.90 |
1.00 |
1.13 |
1.20 |
1.28 |
1.40 |