System Effect & Fan Testing Type

8/7/2019 System Effect & Fan Testing Type

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MEMBER


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MEMBER

My fan isnt performing, come fix it.

I ordered 3,000 cfm at 1 inch

Balancer said I have 2,500 at 3/4 inch.


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MEMBER


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MEMBER

Third party verification - Ethical practices

Information source

Publications / Test Standards

Seminars and service

www.AMCA.org

State-of-the-art testing laboratory

The AMCA International Certified Ratings Program


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MEMBER

Look at Manufacturers printed catalogs- is it the most current / recent? - check AMCA web site

Do you use com puter selection software?- is it licensed / correct formulas? - check AMCA web site

AMCA Internationals web site: www.amca.org


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Test arrangement - shown below cataloged performance data

Performance shown is for Type A, Free inlet, Free outlet

Performance shown is for Type B, Free inlet, Ducted outlet

Performance shown is for Type C, Ducted inlet, Free outlet

Performance shown is for Type D, Ducted inlet, Ducted outlet

If belt driven - does it include drive losses?


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Typical Commercial VentilationTypical Commercial Ventilation

MEMBER

Free inlet, Free outlet (Type A)


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9Free inlet, Ducted outlet (Type B)

MEMBERTypical Commercial VentilationTypical Commercial Ventilation


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O ffice O ff ice

Ducted inlet, Free outlet (Type C)



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11Ducted inlet, Ducted outlet (Type D)



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MEMBER

CFMNew =RPMNew

RPMBasex CFMBase

SPNew =

RPMNew

RPMBase x SPBase

2

BHPNew =

RPMNew

RPMBase x BHPBase

3


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MEMBER

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18

CFM x 100

P

ressure

700 RPM


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MEMBER

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18

CFM x 100

P

ressure

700 RPM

750 RPM

650 RPM


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MEMBER

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 5 10 15 20 25 30 35 40 45

CFM x 100

P

ressure

B

A


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MEMBER

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 2 4 6 8 10 12 14 16 18

CFM x 100

P

ressure

Curve B

Curve A

IncreasingResistance

toflow


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MEMBER

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18

CFM x 100

P

ressure

Fan PerformanceCurve

System Resistance

Curve

Operating Point


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MEMBER

0

0.5

1

1.5

2

2.5

3

3.5

0 5 10 15 20 25 30 35 40 45

CFM x 100

P

ressure

1400 RPM

700 RPM

Operating Point

at 1400 RPM

Operating Point

at 700 RPM


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MEMBER

Operating Point

on Curve B

Operating Point

on Curve A

Operating Point

on Curve B

Operating Point

on Curve A

0

0.5

1

1.5

2

2.5

3

3.5

0 5 10 15 20 25 30 35 40 45

CFM x 100

P

ressure Curve B

Operating Point

on Curve B

Operating Point

on Curve A

Curve A


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MEMBER

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18

CFM x 100

Pressure

0

0.05

0.1

0.15

0.2

0.25

0.3

BrakeHorsePower

Fan Performance Curve

Brake Horsepower Curve


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MEMBER

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12 14 16 18

CFM x 100

Pressure

0

0.05

0.1

0.15

0.2

0.25

0.3

BrakeHorsePowe

r

Fan Performance Curve

Brake Horsepower Curve

System Resistance Curve

Operating Point


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MEMBER


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MEMBER


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MEMBER


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Note: 1) N = New fan speed to achieve design capacity

2) Velocity Pressure = (V/4005)inch-wg.

V = fpm

3) Fan law

P1 / P2 = (N1/N2)

P = Power (kW)

N = Fan speed (rpm)

MEMBER

VP = 1" VP = 0.85" VP = 0.7"

OUTLET


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Note: 1) N= New fan speed to achieve design capacity

2) Velocity Pressure = (V/4005)inch-wg.

V = fpm

3) Fan law

P1 / P2 = (N1/N2)

P = Power (kW)

N = Fan speed (rpm)

MEMBERINLET

VP

= 1" VP

= 0.6"VP

= 0.75"


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Blast AreaCut off

25%

50%

75%

100% Effective Duct Length

OutletArea

DischargeDuct

Centrifugal Fan

Axial Fan

MEMBER


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Effective Duct Length = 2.5 Duct Diameters for2,500 FPM or less

Add 1 duct diameter for each additional 1,000FPM

For rectangular ducts, the equivalent duct

diameter is

MEMBER

4 x width x length


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0.1

0.15

0.2

0.25

0.3

0.4

0.5

0.60.70.80.91.0

1.5

2.0

2.5

3.0

4.0

5.0

5 6 7 8 910 15 20 25 30 35 40 45

FGHIJ K L M N O

P

Q

R

S

T

U

V

W

X

AIR VELOCITY, FPM IN HUNDREDS(AirDensity= 0.075 lbm/ft

3

)

1

2

3

MEMBER


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Axial Fan


No

Duct

12%Effective

Duct

Vaneaxial Fan U V W -- --

Tubeaxial Fan -- -- -- -- --

25%Effective

Duct

75%Effective

Duct

100%Effective

Duct

MEMBER


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0.1

0.15

0.2

0.25

0.3

0.4

0.5

0.60.70.80.91.0

1.5

2.0

2.5

3.0

4.0

5.0

5 6 7 8 910 15 20 25 30 35 40 45

FGHIJ K L M N O

P

Q

R

S

T

U

V

W

X

AIR VELOCITY, FPM IN HUNDREDS

(AirDensity =0.075 lbm/ft3

MEMBER


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Blast Area

NoDuct

12%Effective

Duct

25%Effective

Duct

50%Effective

Duct

100%Effective

Duct

BlastArea Discharge

Duct

Outlet

AreaCutoff

0.4 P R-S U W --

Outlet AreaSystem Effect Curve

0.5 P R-S U W --

0.6 R-S S-T U-V W-X --

0.7 S U W-X -- --

0 .8 T-U V-W X -- --

0 .9 W W-X -- -- --

1 .0 -- -- -- -- --


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Position C

Position B

Position A

Position D

Inlet

MEMBER


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Outlet No 12% 25% 50% 100%

Blas t Area Elbow Out let Effec tive Effec tive Effec tive Effec tive

Outlet A rea Pos ition Duc t Duct Duct Duct Duct

A N O P-Q S

0.4 B M-N N O-P R-S

C L-M M N Q

D L-M M N Q

A O-P P-Q R T

0.5 B N-O O-P Q S-T

C M-N N O-P R-S

D M-N N O-P R-S

A Q Q-R S U0.6 B P Q R T

C N-O O Q S

D N-O O Q S

A R-S S T V

0.7 B Q-R R-S S-T U-V

C P Q R-S T

D P Q R-S T

A S S-T T-U W

0.8 B R-S S T V

C Q-R R S U-V

D Q-R R S U-V

A T T-U U-V W

0.9 B S S-T T-U W

C R S S-T V

D R S S-T V

A T T-U U-V W

1 B S-T T U W

C R-S S T V

D R-S S T V

N

O

SY

S

T

E

M

E

F

F

E

C

T

F

A

C

T

O

R

Position C

Position B

Posi t ion A

Posi t ion D

In le t

MEMBER


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V aneaxial Fan


Tubeaxia l Fan 2 & 4 pc. -- -- -- -- --

Vaneaxia l Fan 2 pc. U U-V V W --

NoDuct

12%Effective

Duct

25%Effective

Duct

50 %Effective

Duct

100%E ffective

Duct

Tubeaxial Fan


90o

Elbow

Vaneaxia l Fan 4 pc. W -- -- -- --

MEMBER


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Example Givens:Centrifugal Fan3,000 cfm at 1 inch static pressure

13 by 13 inch fan discharge / duct size

9 by 13 inch blast area

12 inch duct length

Effective duct length = 2.5 (2,500 FPM or less) + 1 duct for everyadditional 1,000 FPM

Effective duct length = 2.5 + 1 = 3.5 ducts = 3.5 x 14.5 inches = 4 ftEffective duct length is 4 feet

1 ft of duct length = 25% of the effective length

Blast Area / Outlet Area = (9 x 13) / (13 x 13) = 0.7

3,000 cfm / (13 x 13) / 144 = 2556 FPM

MEMBER


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BlastArea DischargeDuct

OutletArea

Cutoff

t

Blast Area

NoDuct

12%Effective

Duct

25%Effective

Duct

50%Effective

Duc

100%Effective

Duct

U W --

System Effect Curve

U W --

U-V W-X --

W-X -- --

X -- --

-- -- --

0.4

Outlet Area

0.5

0.6

0.7

0.8

0.9

1.0 -- -- --

P R-S

P R-S

R-S S-T

S U

T-U VW

W-W W-X

-- --

MEMBER


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System Effect Factor(no duct) = 0.65 inches

Less system effect with

25% effective duct

length

0.1

0.15

0.2

0.25

0.3

0.4

0.5

0.60.70.80.91.0

1.5

2.0

2.5

3.0

4.0

5.0

5 6 7 8 910 15 20 25 30 35 40 45

FGHIJ K L M N O

P

Q

R

S

T

U

V

W

X

AIR VELOCITY, FPM IN HUNDREDS(Air Density = 0.075 lbm/ft

3)

MEMBER


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MEMBER

R

Lengthof Duct

Inlet with 3-pieceelbow

Inlet with rectangularinlet Duct

Inlet with special

designed inlet box


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2 piece miteredround section

3 piece mitered

round section

4 or more piecemitered round

section

R

Lengthof Duct

R

R

Lengthof Duct

Lengthof Duct

D D D

System Effect Curves

R/D NoDuct

2DDuct

5DDuct

-- N P R-S


R/D NoDuct

2DDuct

5DDuct

0.5 O Q S

0.75 Q R-S T-U

1.0 R S-T U-V

2.0 R-S T U-V

3.0 S T-U V


R/D NoDuct

2DDuct

5DDuct

0.5 P-Q R-S T

0.75 Q-R S U

1.0 R S-T U-V

2.0 R-S T U-V

3.0 S-T U V-W

MEMBER


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0.1

0.15

0.2

0.25

0.3

0.4

0.5

0.6

0.70.80.91.0

1.5

2.0

2.5

3.0

4.0

5.0

5 6 7 8 9 10 15 20 25 30 35 40 45

F GH I J K L M N O

P

Q

R

S

T

U

V

W

X

AIR VELOCITY, FPM IN HUNDREDS(AirDensity = 0.075 lbm/ft

3)

Any velocity greaterthan 1500 fpm would

develop a system

effect

MEMBER


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MEMBER


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Lengthof Duct

R


R/D NoDuct

2DDuct

5DDuct

0.5 S T-U V

1.0 T U-V W

2.0 V V-W W -X

HSquare

Lengthof Duct

R

HSquare

Lengthof Duct

R

HSquare


R/D NoDuct

2DDuct

5DDuct

0.5 O Q S

0.75 P R S-T

1.0 R S-T U-V

2.0 S T-U V


R/D NoDuct

2DDuct

5DDuct

0.5 S T-U V

1.0 T U-V W

2.0 V V-W W -X

MEMBER


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MEMBER

Pre-Rotation Counter-Rotation


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MEMBERInlet Swirl


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Design

Pressure

Calculated duct system

Design Volume

Fan pressure-volume curve

MEMBER


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MEMBER

Design Volume

2

3

New Fan Curve

Design Pressure

Actual duct systemwith system effect

System effect atactual flow volume System effect loss

at design volume

Calculated duct systemwith no allowance forsystem effect

Original Fan Curve

Deficient Volume Performance

11

3

2

4


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Minimum 2.5 duct diameters on Outlet

Minimum 5 to 8 duct diameters on Inlet

Avoid inlet swirl

If any of these general rules are broken, make

sure to take system effect into account.


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C-D duct friction 750 Pa (duct design)A free inlet 0 Pa (no SEF)

B-C outlet with straight duct attached

for 2 or more dia. 0 Pa (no SEF)

--------------------------------

REQUIRED Fan Ps 750 Pa

MEMBER


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E-F duct friction at 5000CMH (Q) 750 Pa (duct design)

E contraction loss-plenum to duct 50 Pa (part of duct system)

E Ps energy required to create velocity at E 125 Pa (part of duct system)

D Pv loss (also Pt loss) at D as result of air velocity decrease 0 Pa

Ps does not change from duct to plenum at D

C-D outlet duct on fan as tested 0 Pa

--------------------


MEMBER

MEMBER


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D-E duct friction at 5000CMH (Q) 750 Pa (duct design)

D contraction loss-plenum to duct 50 Pa (part of duct system)D Ps energy required to create velocity at D 125 Pa (part of duct system)

B-C SEF 150 Pa

B-C Pv loss (also Pt loss) at C as result of air velocity decrease 0 Pa

Ps does not change from duct to plenum at C

------------------


MEMBER


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A Entrance loss-sharp edge duct 100 Pa (duct design)

A-B Duct friction at 5000CMH 750 Pa (duct design)

B SEF 1 150 Pa

C SEF 2 50 Pa

E Fan Pv 125 Pa

E SEF 3 150 Pa

------------------

REQUIRED Fan Pt 1325 Pa

Fan Ps = fan Pt fan Pv

Fan Ps = 1325 Pa 125 Pa

Fan Ps = 1200 Pa

MEMBER


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Highefficient fan

1

Wide productrange to

meet differentoperation

point

2 3 4

Technicalsupport to

ensure a goodmatch of fan

and system

Proper

system

design and

TAB

MEMBER


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Documents

System Effect & Fan Testing Type