Duct fitting pressure drop coefficients for
rectangular and round wyes

From ASHRAE (1989), with permission

A5-6k.gif (14342 bytes)

Values of Cc,1b or Cc,2b for a converging Wye

 

 

V1b / Vc or V2b / Vc

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

q, deg

15

-2.6

-1.9

-1.3

-0.77

-0.30

0.10

0.41

0.67

0.85

0.97

1.0

30

-2.1

-1.5

-1.0

-0.53

-0.10

0.28

0.69

0.91

1.1

1.4

1.6

45

-1.3

-0.93

-0.55

-0.16

0.20

0.56

0.92

1.3

1.6

2.0

2.3

Values of Cc,1b or Cc,2b for a diverging Wye

 

V1b / Vc or V2b / Vc

0.1

0.2

0.3

0.4

0.5

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

q, deg

15

0.81

0.65

0.51

0.38

0.28

0.20

0.11

0.06

0.14

0.30

0.51

0.76

1.0

30

0.84

0.69

0.56

0.44

0.34

0.26

0.19

0.15

0.15

0.30

0.51

0.76

1.0

45

0.87

0.74

0.63

0.54

0.45

0.38

0.29

0.24

0.23

0.30

0.51

0.76

1.0

60

0.90

0.82

0.79

0.66

0.59

0.53

0.43

0.36

0.33

0.39

0.51

0.76

1.0

90

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0

1.0