AMCA FiguresFigure 5.3 illustrates a fully ducted damper. This configuration hasthe lowest pressure drop of the three test configurations becauseentrance and exit losses are minimized by straight duct runsupstream and downstream of the damper.Figure 5.2 illustrates a ducted damper exhausting air into an openarea. This configuration has a lower pressure drop than Figure 5.5because entrance losses are minimized by a straight duct runupstream of the damper.Figure 5.5 illustrates a plenum mounted damper. This configurationhas the highest pressure drop because of extremely high entranceand exit losses due to the sudden changes of area in the system.

Ruskin pressure drop testing was conducted in accordance withAMCA Standard 500-D using Figure 5.3. All data has been cor-rected to represent standard air at a density of .075 lb/ft3(1.201kg/m3).Actual pressure drop found in any HVAC system is a combina-tion of many factors. This pressure drop information along withan analysis of other system influences should be used to esti-mate actual pressure losses for a damper installed in a givenHVAC system.

For AMCA Certified Ratings Air Performance informationrefer to the damper model specification sheet.

ALL STATED SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE OR OBLIGATION. ©Ruskin 2009PDD-109/New

3900 Dr. Greaves Rd. • Kansas City, MO 64030 • (816) 761-7476 • FAX (816) 765-8955

PRESSURE DROP DATA

FREE AREA FACTORS

GALVANIZED STEEL AIRFOIL BLADE DAMPERS

The tables below provide the free area in square feet for each sizeindicated. For example, the galvanized steel airfoil blades damper

table shows a 24” x 24” damper has 2.52 square feet or 63%(2.52/4) of free area.

HeightDamper B

Dim.8

10

12

14

16

18

20

24

28

32

36

40

44

48

0.17

0.24

0.29

0.32

0.39

0.44

0.51

0.64

0.78

0.91

1.03

1.18

1.30

1.42

0.29

0.42

0.51

0.55

0.68

0.77

0.90

1.11

1.37

1.58

1.79

2.05

2.26

2.47

0.42

0.60

0.72

0.79

0.98

1.09

1.28

1.58

1.95

2.25

2.55

2.93

3.23

3.53

0.54

0.78

0.94

1.03

1.27

1.42

1.66

2.05

2.53

2.93

3.32

3.80

4.19

4.59

0.67

0.97

1.15

1.26

1.56

1.74

2.04

2.52

3.12

3.60

4.08

4.68

5.16

5.64

0.79

1.15

1.37

1.50

1.85

2.07

2.42

3.00

3.70

4.27

4.85

5.55

6.12

6.70

0.86

1.24

1.47

1.62

2.00

2.23

2.61

3.23

3.99

4.61

5.23

5.99

6.61

7.22

8 12 16 20 24 28 30

0.92

1.33

1.58

1.75

2.16

2.40

2.81

3.47

4.30

4.97

5.64

6.46

7.13

7.78

32

Width - Damper A Dim.

TRIPLE V-GROOVE BLADE DAMPERS

HeightDamper B

Dim.8

10

12

14

16

18

20

24

28

32

36

40

44

48

0.18

0.23

0.30

0.33

0.40

0.44

0.53

0.62

0.78

0.93

1.05

1.19

1.32

1.45

0.31

0.40

0.53

0.58

0.69

0.77

0.92

1.09

1.35

1.62

1.83

2.08

2.31

2.52

0.45

0.57

0.76

0.82

0.99

1.10

1.32

1.55

1.93

2.31

2.61

2.96

3.29

3.60

0.58

0.74

0.98

1.07

1.28

1.43

1.71

2.01

2.50

2.99

3.39

3.85

4.28

4.68

0.71

0.91

1.21

1.32

1.58

1.76

2.11

2.48

3.08

3.68

4.18

4.73

5.26

5.75

0.85

1.08

1.53

1.56

1.87

2.09

2.50

2.94

3.66

4.37

4.96

5.62

6.25

6.83

0.98

1.25

1.66

1.81

2.17

2.42

2.89

3.40

4.23

5.06

5.74

6.50

7.23

7.91

1.12

1.42

1.88

2.06

2.46

2.75

3.29

3.87

4.81

5.75

6.52

7.39

8.21

8.98

8 12 16 20 24 28 32 36

Width - Damper A Dim.

ALUMINUM AIRFOIL BLADE DAMPERS

HeightDamper B

Dim.8

10

12

14

16

18

20

24

28

32

36

40

44

48

0.18

0.24

0.31

0.35

0.41

0.48

0.56

0.69

0.82

0.97

1.10

1.23

1.36

1.51

0.32

0.42

0.55

0.61

0.71

0.83

0.97

1.20

1.43

1.69

1.91

2.14

2.37

2.63

0.45

0.59

0.78

0.87

1.01

1.20

1.38

1.71

2.03

2.41

2.73

3.06

3.38

3.75

0.59

0.77

1.01

1.13

1.31

1.56

1.80

2.22

2.64

3.12

3.55

3.97

4.39

4.87

0.72

0.95

1.24

1.39

1.62

1.91

2.21

2.73

3.25

3.84

4.36

4.88

5.40

6.00

0.86

1.12

1.48

1.66

1.92

2.27

2.62

3.24

3.86

4.56

5.18

5.80

6.41

7.12

0.99

1.30

1.71

1.92

2.22

2.63

3.04

3.75

4.47

5.28

6.00

6.71

7.42

8.24

1.13

1.48

1.94

2.18

2.52

2.99

3.45

4.26

5.07

6.00

6.81

7.62

8.43

9.36

8 12 16 20 24 28 32 36

Width - Damper A Dim.

PRESSURE DROP DATA FOR GALVANIZED STEEL AIRFOIL BLADE DAMPERSThe pressure drop data in the tables below is for fully ducteddampers as represented by Figure 5.3 on page 1. For dampers notfully ducted, represented by Figure 5.2 and Figure 5.5 on page1, use one of the correction factors from the tables at the bot-tom of this page.For example, the pressure drop across a 24” x 24” (610 x 610)damper in an air system with a velocity of 1,000 FPM is .03 inchesw.g. If the application more closely resembles Figure 5.2, the actualpressure drop is closer to .09 inches w.g. (.03 x 3).

IMPORTANT NOTE: Algorithmic calculations were used to deter-mine the pressure drop and correction factors shown below. Theactual pressure loss may be higher due to bad flow profiles. A badflow profile includes an application where there is less than oneduct diameter between the damper and any element. Bad flowprofiles may require an increase of the correction factor by 1.5times.

PRESSURE DROP DATA FOR TRIPLE V-GROOVE BLADE DAMPERThe pressure drop data in the tables below is for fully ducteddampers as represented by Figure 5.3 on page 1. For dampers notfully ducted, represented by Figure 5.2 and Figure 5.5 on page 1,use one of the correction factors from the tables at the bottom of thispage.For example, the pressure drop across a 24” x 24” (610 x 610)damper in an air system with a velocity of 1,000 FPM is .06 inchesw.g. If the application more closely resembles Figure 5.2, the actualpressure drop is closer to .18 inches w.g. (.06 x 3).

IMPORTANT NOTE: Algorithmic calculations were used to deter-mine the pressure drop and correction factors shown below. Theactual pressure loss may be higher due to bad flow profiles. A badflow profile includes an application where there is less than oneduct diameter between the damper and any element. Bad flowprofiles may require an increase of the correction factor by 1.5times.

PRESSURE DROP DATA FOR ALUMINUM AIRFOIL BLADE DAMPERSThe pressure drop data in the tables below is for fully ducteddampers as represented by Figure 5.3 on page 1. For dampers notfully ducted, represented by Figure 5.2 and Figure 5.5 on page 1,use one of the correction factors from the tables at the bottom of thispage.For example, the pressure drop across a 24” x 24” (610 x 610)damper in an air system with a velocity of 1,000 FPM is .02 inchesw.g. If the application more closely resembles Figure 5.2, the actualpressure drop is closer to .06 inches w.g. (.02 x 3).

IMPORTANT NOTE: Algorithmic calculations were used to deter-mine the pressure drop and correction factors shown below. Theactual pressure loss may be higher due to bad flow profiles. A badflow profile includes an application where there is less than oneduct diameter between the damper and any element. Bad flowprofiles may require an increase of the correction factor by 1.5times.

3900 Dr. Greaves Rd.Kansas City, MO 64030(816) 761-7476FAX (816) 765-8955www.ruskin.com