Sound Attenuator 2014 - dvac-duct.infodvac-duct.info/wp-content/uploads/2014/04/Sound-Attenuator-2014.pdf · - Aluminum Metal : (Optional) ... The Outer Casing and Perforated Inner

SOUND ATTENUATORS

Sound Attenuators

DUCT VENTILATION AIR CONDITIONING Co. (W.L.L.)


DOHA- QATAR - PHONE: +974-44500118 - +974-44500119 - FAX: +974-44500117

DVAC, One Of The Premium Workshops Specialized in Duct Fabrication,

has Executed Several Projects

(Residential, Governmental, Commercial, Industrial & Institutional).

Sound Attenuators

2



Rectangular Sound Attenuator

Circular Sound Attenuator

Calculation & Selection

Insulation

NC and NR Schedules

Customer Selection Order

PageSound Attenuators: - Rectangular and Circular

4

5

7

9

10

12

Table of Contents

3



4

Sound Attenuators

Rectangular Sound Attenuator

RTYPE: SA

Type : SA / SA / SAs R CA CB

Rectangular CircularAnd

* Used for sMaterials Sound Attenuator :- Galvanized Steel: (Standard) L.F.Q. Complying with ASTM A653 and Having G90 Coating Designation.

24 M A M- Stainless Steel : (Optional) Complying with ASTM A 0 / 480 , Grade 304, 304L, 316, & 316L.

A T- Aluminum Metal : Complying with ASTM B209, lloy 3003, emper H14.(Optional)

GENERAL:

The Sound Attenuator is Mainly Used to Reduce FCU and AHU Noise to Obtain he Required Noise Level.t

The Sound Attenuator Offers Many Advanced Features Including as a Standard Aerodynamic Splitters,,

,Side Liners Slide on Flange and Protect Acoustic Infill by Galvanized Perforated Sheet Metal.

3

1 Constructed of Galvanized Steel Sheet.Casing: 22 Gage (minimum)

Standard Length 600 - 900 - 1200 - 1500 - 1800 - 2100 - 2400 - 3000mm

2 Connectors: Slip-on Flanges 20mm, 30mm, 40mm or Companion Angle

(Depending on the Sound Attenuator Size).

3 , Filled rAcoustic Flat Panel Baffle(s): Constructed of Galvanized Steel Sheet with Fibe glass

32 ity 25mm or T nessInsulation kg/m Dens , 50mm hick with Glass Cloth Facing Around3

the Galvanized Steel Sheet.

Sizes 100 - 150 - 200 - 250 - 300mm.The Width of Acoustic Flat Panel Baffle(s)

All Surfaces of Fibe glass with Glass Cloth Facing are Covered by Perforated4 rPerforated Sheets:

, rotecting er .Galvanized Steel Sheet P All Fib glass Surfaces from Erosion

Perforated Sheet, Free Area 22.5% to Avoid High Pressure Drop.

ll dges of ib glass at ntrance and xit of ectangular uct ilencer5 A E F er E E R D SSolid Bell Mouths:

C G S l S S B M P Fare overed with alvanized tee heet as olid ell ouths rotecting all iberglass

E s M A Tdge and inimizing ir urbulence.

ealed all oints of erforated alvanized teel heets, all oints etween olid6 S J P G S S J B SSilicone Sealants:

R S B M P G S S Founded Noses, olid ell ouths and erforated alvanized teel heets to urther

F P F E .Ensure ull rotection of all iberglass dges

FEATURES:

2

1

5 4 6



5




L

d

Sound AttenuatorsRectangular CircularAnd

D

Circular AttenuatorSound

TYPE: CASA

d + 100mm D = Insulation Thickness: 50mm∅ ∅

d + 200m D = Insulation Thickness: 100mmm∅ ∅

Size(mm)

Plain Flange(Standard Diameter of Holes 9.0mm)

b x t(mm)

k(mm)

No. ofHoles

100125150

25 x 325 x 325 x 3

130155180

445

200250300

25 x 325 x 325 x 3

225275325

668

400450500

30 x 330 x 330 x 3

430480530

888

550600700

40 x 440 x 440 x 4

590640740

121212

800900

1000

40 x 440 x 440 x 4

840940

1040

161616

k

∅ ∅

d∅∅

b

∅


- Type Circular Attenuat Intended Use i Ventilation Systems.CASA or is to be d n

The Outer Casing and Perforated Inner Duct are alvani ed Sheet Steel;Fabricated of G z

Insulation Thickness 50mm or 100mm.

The Non-combustible Acoustic Material is Protected from Air Flow Erosion by .Glass Cloth

The Inlet and Outlet Connections Can Either be Plug-type Spigot Flanged.or



6





Size(mm)

Plain Flange(Standard Diameter of Holes 9.0mm)

b x t(mm)

k(mm)

No. ofHoles

100125150

25 x 325 x 325 x 3

130155180

445

200250300

25 x 325 x 325 x 3

225275325

668

400450500

30 x 330 x 330 x 3

430480530

888

550600700

40 x 440 x 440 x 4

590640740

121212

800900

1000

40 x 440 x 440 x 4

840940

1040

161616

k d∅∅

b

∅


D∅ ∅

L

d

Circular AttenuatorSound

TYPE: CBSA

The Outer Casing and Perforated Inner Duct are alvani ed Sheet Steel; Insulation Thickness 5 mm or 100mmG z 0 .

Glass ClothThe Non-combustible Acoustic Material is Protected from Air Flow Erosion by .

he Inlet and Outlet Connections Can Either be Plug-type Spigot Flanged and Have an AdditionalT or ,

r zSound-absorbing Pod Fitted in the Cente with a Galvani ed Perforated Sheet Covering and Coned end

to Reduce Pressure Loss.

- Type Circular Attenuat Intended Use i Ventilation SystemsCBSA or is to be d n .

d + 100mm D = Insulation Thickness: 50mm∅ ∅

d + 200m D = Insulation Thickness: 100mmm∅ ∅



7




Calculation

To Make the Calculation, DVAC Works on Silencer Software Dimensionthe which Provides the Exact s

to be Applied for the Fabrication , .of the Silencer Depending on the Sound Level Required by the Customer


Input Required Data:

1- In Duct Sound Power Level

Or Sound Pressure Level

2- Distance Between the Fan

And The First Opening

3- Volume Flow Rate

4- Type of Silencer

5- Sound Level & Size

Output Data:

There are Several Options

to Make Selection of Silencers.

The Selection will be Done

According to the Data Provided.




8

500 Hz

82

+1

83

82

28

54

+1

55

-0

-28

38

18

-9

29

1 KHz

81

+1

82

81

32

49

+1

50

-0

-28

21

8

0

21

2 KHz

79

+1

80

79

24

55

+1

56

-0

-28

27

6

1

28

4 KHz

71

+1

72

71

19

52

+1

53

-0

-28

24

1

1

25

8 KHz

63

+1

64

63

16

47

+1

48

-0

-28

19

-6

-1

18

Total

93

94

93

80

81

48

30

34

63 Hz

88

+1

89

88

9

79

+1

80

-5

-28

46

28

-26

20

125 Hz

87

+1

88

87

14

73

+1

74

-2

-28

43

22

-16

27

250 Hz

87

+1

88

87

21

66

+1

67

-0

-28

38

18

-9

29

.

Source Noise In Duct SWL

Duct Area Correction dB

In Duct SPL dB (Ref Only)

In Duct SWL dB

Silencer Insertion Loss (SWL) dB

In Duct SWL after Silencer dB

In Duct Area Correction dB

Duct SPL dB (Ref Only)

Correction for End Reflection

Correction for Distance @ 10.5 metres

Final SPL dB @ 10.5 metres

Silencer Regen Noise db @ 10.5 metres

Correction for “A” Weighting

Final SPL dBA @ 10.5 metres

SWL = Sound Power Level dB re 10^-12watts (picoWatts)

SPL = Sound Pressure Level dB re 2 X 10^-5 N/M2 (20microPascals)

Sound Levels are Averages and do not Include Directivity Factors

Distance Corrections are Free Field Using Hemispherical Radiation.

Rectangular Silencer Style 2 Outer Body 1.6mm Thick.

Volume Flow = 3040 L/S

Internal Flange Dimensions : 550mm x1400mm x1200mm Face to Face

550mm Wide 1 1100mm Long Splitters. - 2 Side Splitters 150mm Thick. 2 x Internal Splitters 300mm Thick.

External Dimensions 1403.2mm x 553.2mm x1200mm Long

Gap Between Splitters = 167mm. Air Velocity in the Gap = 11.0 m/s

Minimum Infill Density = 50 Kg/m3

LOSSES:

Friction Loss = 23.0 Pascals

Velocity Pressure Difference Between the Gap Vp and Equipment Vp is 64.0 Pascals

The Velocity Pressure Difference Can be Significant Under Certain Applications

DVAC Phone 4500119. Fax 4500117. www.dvac-duct.com

Ref. FCU-1

22/04/2009




Date : 22/04/2009 REF : FCU-1

1.6mm Th’K

1200

533

OUTSIDE

530

INSIDE

1403

OUTSIDE

1400

INSIDE

300

150167

2 Splitters with 3 equal gaps of 167mmNTS

65mm Wide Flanges


The Selected Silencer

is Followed Up With Data Sheet

Containing the Following

Output Calculations:

- Size, W/H/L

- Number of Baffles

- Gap Between Baffles

- Output Noise Level

- Losses

Sketch Of The Selected Silencer

The Software Issues a Sketch

Showing Construction Details.

N.B. : The Software Selection is based on Perforated Sheet, Free Area 22.5% to Avoid High Pressure Drop.




9




ACOUSTIC INFILL:

The "Acoustic Infill" Materials are Dimensionally Stable Under Varying Conditions of Temperature and Humidity,

Rot Proof, Odorless, Non-hygroscopic and do Not Sustain Vermin or Fungus.

They do not Shrink Due to the Age or Temperature Variations.

The "Acoustic Infill" Tested to the Following Tests:

- Surface Burning Characteristics: ASTM E 84, BS 476, UL 723.

- Moisture Absorption: BS 2972 and 6676, ASTM C 665.

- Fire Resistance: NFPA 90A and 90B.

- Acoustic Performance: ASTM C1071, ASTM C423.



RECTANGULAR SOUND ATTENUATOR

ROUND SOUND ATTENUATOR



10




Recommended Noise Criterion - NCThe Noise in Different Types of Rooms Should not Exceed the Noise Criterion Limits Listed Below:


Type Of Room - Space TypeRecommended

NC Level

EquivalentSound Level

dBA

Apartments, Meeting Rooms 25-35 35-45

Assembly Halls 25-30 35-40

Service and Support Areas 40-45 50-55

Halls, Corridors, Lobbies 35-40 45-50

Offices

Conference Rooms 25-30 35-40

Private 30-35 40-45

Open-Plan Areas 35-40 45-50

Business Machines Computers, 40-45 50-55

Hospitals and Clinics

Private Rooms, Operating Rooms 25-30 35-40

Wards, Corridors 30-35 40-45

Laboratories, Public Areas 35-40 45-50

Type Of Room - Space TypeRecommended

NC Level

EquivalentSound Level

dBA

Schools

Lecture and Classrooms 25-30 35-40

Open-plan Classrooms 35-40 45-50

Movie Motion Picture Theaters 30-35 40-45

Librairies 35-40 45-50

Legitimate Theaters 20-25 30-35

Private Residences 25-35 35-45

Restaurants 40-45 50-55

TV Broadcast Studies 15-25 25-35

Recording Studios 15-20 25-30

Concert and recital Halls 15-20 25-30

Sport Coliseums 45-55 55-65

Sound Broadcasting 15-20 25-30


Noise Rating Curve Application

NR 25 Concert Halls, Broadcasting and Recording Studios, Churches

NR 30 Private Dwellings, Hospitals, Theatres, Cinemas, Conference Rooms

NR 35Libraries, Museums, Court Rooms, Schools, Hospitals Operating

Theatres and Wards, Flats, Hotels, Executive Offices

NR 40 Halls, Corridors, Cloakrooms, Restaurants, Night Clubs, Offices, Shops

Nr45 Department Stores, Supermarkets, Canteens, General Offices

NR 50 Typing Pools, Offices With Business Machines

NR 60 Light Engineering Works

NR 70 Foundries, Heavy Engineering Works

Recommended Noise Rating - NR - LevelsThe Noise Rating Level for Different Uses Should not Exceed the Noise Ratings Indicated in the Table Below:



11






Recommended Noise Rating - NR - LevelsThe Noise Rating Level for Different Uses Should not Exceed the Noise Ratings Indicated in the Table Below:

Maximum Sound Pressure Level (dB)

Noise Rating- NR -Curve

Octave Band mid-frequency (Hz)

31.5 62.5 125 250 500 1000 2000 4000 8000

NR 0NR 10NR 20NR 30NR 40NR 50NR 60NR 70NR 80NR 90NR 100NR 110NR 120NR 130

55626976838996

103110117124130137144

364351596775839199

107115122130138

223139485766748392

100109118126135

12213140495968778696

105114124133

5152434445463738393

102112122131

0102030405060708090

100110120130

-47

172737475768788898

108118128

-64

142535455566768696

107117127

-82

132333445464748595

105116126

0

10

20

30

40

50

60

70

80

90

63 125 250 500 1000 2000 4000 8000

EXAMPLE - ESTIMATING NC - NOISE CRITERIAThe Noise Criterion - NC - of a Noise Spectrum Like:

*62.5 Hz: 40 dB

*125 Hz: 50 dB

*250 Hz: 55 dB

*500 Hz: 60 dB

*1000 Hz: 50 dB

*2000 Hz: 55 dB

*4000 Hz: 45 dB

*8000 Hz: 45 dB

Can be Estimated to NC = 57dB

Belowas Indicated in Diagram:

NC 15NC 20NC 25NC 30NC 35NC 40NC 45NC 50NC 55NC 60NC 65NC 70

Sound P

ressure

Level (d

B)

Frequency (Hz)



12




Ord

er

No.:

To : D

VA

C -

Duct V

entila

tion

Air C

onditio

nin

gW

..

(L L

)

Attn. : E

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epart

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Tel : +

974 4

500118 / 1

19

Fax : +

974 4

500117

Com

pany N

am

e : _

___________________________________

Conta

ct P

ers

on : ____________________________________

Pro

ject N

am

e : _

___________________________________

Tel : _

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Type : SA / SA / SAs R CA CBD

ate

: / /

Cu

sto

mer

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on

Ord

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Item

Refe

rence

Qty

Duct S

ize

Volu

me F

low

Rate

Dis

tance

Betw

een

Fan to 1

st.

Grille

Nois

eLevel

De

sire

d

Fan

Sta

tic

Pre

ssure

In D

uct

Pow

er

Sound

Level

Wid

th(m

m)

He

igh

t(m

m)

Dia

m.

(mm

)C

FM

L/S

(m)

dB

AP

a63 H

z125 H

z250 H

z500 H

z1 K

hz

2 K

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4 K

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Sig

na

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13




Ord

er

No.:

To : D

VA

C -

Duct V

entila

tion

Air C

onditio

nin

gW

.(

L.L

)

Attn. : E

ngin

eering D

epart

ment

Tel : +

974 4

500118 / 1

19

Fax : +

974 4

500117

Com

pany N

am

e : _

___________________________________

Conta

ct P

ers

on : ____________________________________

Pro

ject N

am

e : _

___________________________________

Tel : _

___________________________________

Fax : _

___________________________________


Type : SA / SA / SAs R CA CBD

ate

: / /

Cu

sto

mer

Sele

cti

on

Ord

er

Item

Refe

rence

Qty

Duct S

ize

Volu

me F

low

Rate

Dis

tance

Betw

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Fan to 1

st.

Grille

Nois

eLevel

De

sire

d

Fan

Sta

tic

Pre

ssure

In D

uct

Pre

ssure

lS

ound

Leve

Wid

th(m

m)

He

igh

t(m

m)

Dia

m.

(mm

)C

FM

L/S

(m)

dB

AP

a63 H

z125 H

z250 H

z500 H

z1 K

hz

2 K

hz

4 K

hz

8 K

hz

D (m)

Sig

na

ture

:N

ote

s :

14

Remarks:

DOHA - QATAR - PHONE: +974-44500118 - +974-44500119 - FAX: +974-44500117

15

Remarks:

DOHA - QATAR - PHONE: +974-44500118 - +974-44500119 - FAX: +974-44500117

Small Industries Zone - Pink AreaZone 81 - Street 13 - Bldg. 57

Tel: +974 445 00 118 - 445 00 119Fax: +974 445 00 117P.O. Box: 55619 - Doha, State Of Qatar

Email: [email protected]: www.dvac-duct.com


Documents

Sound Attenuator 2014 - dvac-duct.infodvac-duct.info/wp-content/uploads/2014/04/Sound-Attenuator-2014.pdf · - Aluminum Metal : (Optional) ... The Outer Casing and Perforated Inner