Duct fitting pressure drop coefficients for
converging round tee

From ASHRAE (1989), with permission

A5-6g.gif (11083 bytes)

Branch Cc,b

Ab / Ac

0.1

0.2

0.3

0.4

0.6

0.8

1.0

Vb / Vc

0.0

-1.0

-1.0

-1.0

-0.90

-0.90

-0.90

-0.90

0.1

0.40

-0.37

-0.51

-0.46

-0.50

-0.51

-0.52

0.2

3.8

0.72

0.17

-0.02

-0.14

-0.18

-0.24

0.3

9.2

2.3

1.0

0.44

0.21

0.11

-0.08

0.4

16

4.3

2.1

0.94

0.54

0.40

0.32

0.5

26

6.8

3.2

1.1

0.66

0.49

0.42

0.6

37

9.7

4.7

1.6

0.92

0.69

0.57

0.7

43

13

6.3

2.1

1.2

0.88

0.72

0.8

65

17

7.9

2.7

1.5

1.1

0.86

0.9

82

21

9.7

3.4

1.8

1.2

0.99

1.0

101

26

12

4

2.1

1.4

1.1


Main Cc,s

Vb / Vc

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8 0.9

1.0

Cc,s

0 0.16 0.27 0.38 0.46 0.53 0.57 0.59 0.60 0.59 0.55