6S1 Sound Attenuators

6/S1

Sound Attenuators

Rectangular Sound Attenuator PZ

Round Sound Attenuator PZC

Interspace Sound Attenuator PZM

Sound Attenuating Splitters PK

Clean and Comfort Air You Breath

2

Sound Attenuators

2

Rectangular sound attenuators, type PZ, are designed for air conditioning and ventilation systems. Splitters are made of nonflammable, sound absorbing rock wool. Sig-nificant sound attenuation occurs in frequency range of 63 to 8000 Hz. Splitter surface is resistant to particle erosion up to air velocities of 20 m/s. Splitters are constructed in three standard thicknesses: d = 100 mm, d = 200 mm and d = 300 mm. Rectangular sound attenuators are available in five standard cross-section dimensions: d/s = 100/50; 100/100; 200/100; 200/200 and 300/100. Attenuator cas-ing is made of galvanised steel, fitted with flanges meeting criteria given in the table on page 3. Unless specified on order, flanges are normally supplied without holes.Attenuators heavier than 300 kg are supplied in two or more sections, each single section lighter than 300 kg. Alldimensions of sound attenuators and splitters are stan-dardised. On customer's order and at additional cost, they can be manufactured in other required dimensions, and made of stainless steel.

Attenuator casing made of sheet metal

Selection of the Splitter Cover (Lining)

Glass fibre veil (V) - Very thin protective cover on the splitter surface; usual, most frequently applied design. The splitter surface is air-permeable, less permeable for water, prevents erosion (up-lift of mineral wool particles) causedby air circulation.Glass fibre silk (S) - Very thin protective cover (only 0.12

Possible clearances, re-sulting from the splitter and duct height difference,should be sealed with sound reducing material in order to prevent nonat-tenuated propagation of sound energy.

Rectangular Sound Attenuator, Type PZ and Sound Attenuator Splitters, Type PK

Flange dimension criterium

Absorption material rock-wool, non-flammable, according to Class A2, to HRN (Croatian norms) and DIN 4102, Part 1.Maximum permitted continuous operating temperature is 250C.Due to sound transmission through tin plates of attenuator casing, the highest achievable insertion loss amounts to 40 dB. If a higher value is required, total loss should be divided into two elastically coupled attenuators.

Besides given cover types, combined covers are also available (see Ordering example on page 14).Acoustic properties of klimaoprema sound attenuators are tested acc. to ISO 7235, by Heat and Thermal Devices Laboratory, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Croatia.

Splitters installed directly into the duct by means of distance strappings

mm) applied to the splitter surface by special process. The splitter surface - low air-permeability, impermeable for water, prevents erosion (up-lift of mineral wool par-ticles) caused by air circulation.Reflective plates (R) - Half of each side of the splitter (alternatively centre up and centre down) is fitted with galvanised tin plates, giving the splitter better attenuation characteristics at frequency of 250 Hz.Perforated plates (P) - At air velocities higher than 20 m/s, or when polluted air is a medium, the splitters should be fitted with protective perforated galvanised plates, having no significant effect on noise attenuation.

Flange type

Parameter

Rolled profile(galvanised)width 30mm

Formed steel angle flange (anti corrosive

painted)L 35 x 35 x 4

Formed steel angle flange (anti-corrosive

painted)L 40x 40 x 4

Attenuator weightG ≤ 300 kg +

> 300 kg + On request only

Attenuator cross-section area

A ≤ 1.2 m2 +> 1.2 m2 + On request only

Longer side of the cross-section

≤ 1500 mm +> 1500 mm + On request only

Application

Design Changes Reserved 3

Sound Attenuators

3

Standard Sizes and Weights of Sound Attenuators (Model without reflection plates or without perforated plate covers of splitters)

Duct width B (mm)

Duct width B (mm)

Legend:- 2-sectional attenuator

- 4-sectional attenuator

4

Sound Attenuators

4

Standard Sizes and Weights of Sound Attenuators (Model with reflection plates or with perforated plate covers of splitters)

Duct width B (mm)

Duct width B (mm)

Legend:- 2-sectional attenuator

- 4-sectional attenuator


Sound Attenuators

5

Sketches of Two-sectional Attenuators

Kao πto se na skicama vidi, dijelovi priguπivaËa se meusobno spajaju pomoÊu prigraenih prirubnica i vijaka. Dodirne se plohe, po potrebi uËvrπÊuju i dodatnim natiËnim dræaËima.S viπedjelnim priguπivaËem isporuËuju se i pocinËani ËeliËni vijci. Svaki se viπedjelni priguπivaË u tvornici prije isporuke probno sastavlja i rastavlja.

Sketch of Four- and Eight-sectional Attenuator

- Connection along width

- Connection along length

- Connection along height

As seen in the sketches, sections of the attenuator are connected with built-in flanges and bolts. Contact flange surfaces can be additionally fixed by reinforcement holders.Galvanised steel bolts are delivered with attenuators consisting of more sections. Prior to attenuator delivery, sections of each attenuator are assembled and disassembled in the factory.

6

Sound Attenuators

6

1. Insertion Loss (attenuation) Diagrambr

zina

zra

ka v

ef [

m/s

]

otpo

r ∆

p [

Pa]

koliËina zraka V [m3/H] x 103

2. Selection Diagram Cross-section and Air Pressure Drop

Type PZ 100/50

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Air

velo

city

vef [

m/s

]

Air flow rate V [m3/h] x 103

Air

Pre

ssur

e dr

op ∆

p [P

a]

Width B [mm]

Number of splitters


Sound Attenuators

7

brzi

na z

raka

vef

[m

/s]

otpo

r ∆

p [

Pa]

3. Insertion Loss (attenuation) Diagram


Type PZ 100/100


Air

velo

city

vef [

m/s

]


Air

Pre

ssur

e dr

op ∆

p [P

a]

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Width B [mm]

Number of splitters

8

Sound Attenuators

8

5. Insertion Loss (attenuation) Diagram Type PZ - R 100/50

Example:Given:Air volume rate: V=5500 m3/hRequired attenuation: 24 dB (A) at 250 Hz

Solution:Diag. 1: PZ-R 100/50 Attenuator length: L = 1480 mm

Diag. 2: Effective air velocity vef = 5.5 m/s Air Pressure drop ∆ ptot = 17 Pa Attenuator cross-section: B x H = 1350 x 600 ili 900 x 900

Diag. 7: Frequency Hz 125 250 500

Flow regenerated noise dB (A) 39 31 27Atot = B x H= 0.81 m2

Tab. 9: Correction dB (A) -2 -2 -2

Total air flow regenerated noise dB (A) 37 29 25

In each octave band noise values determined above have to be by 9 dB(A) lower than the attenuated source noise measured after the attenuator (see Figure).

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Sound attenuator

Source noisebefore attenuator

Remaining noisemeasurement point


Sound Attenuators

9

6. Insertion Loss (attenuation) Diagram Type PZ - R 100/100

7. Dijagram protoËnih πumnosti za d/s = 100/100 (vrijedi za B x H = Atot = 1 m2)

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

7. Air Flow Regenerated Noise Diagram for d/s = 100/50 (based on outlet size B x H = Atot = 1m2)

8. Air Flow Regenerated Noise Diagram for d/s = 100/100 (based on outlet size B x H = Atot = 1m2)

Air velocity vef [m/s] Air velocity vef [m/s]

Sou

nd p

ower

leve

l [dB

]

Sou

nd p

ower

leve

l [dB

]

9. Correction Table

Correction db(A)

10

Sound Attenuators

10

1. Insertion Loss (attenuation) Diagram Type PZ 200/100


otpo

r ∆

p [

Pa]


Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Air

velo

city

vef [

m/s

]


Air

Pre

ssur

e dr

op ∆

p [P

a]

Width B [mm]

Number of splitters


Sound Attenuators

11

3. Insertion Loss (attenuation) Diagram Type PZ 200/200


koliËina zraka

Air

velo

city

vef [

m/s

]


Inse

rtio

n lo

ss [d

B]

Frequency [Hz]

Width B [mm]

Number of splitters

Air

Pre

ssur

e dr

op ∆

p t [P

a]

12

Sound Attenuators

12


Selection Diagrams for Rectangular Splitter Attenuators

Type PZ - R 200/100

Example:Given:Air volume rate: V = 1800 m3/hRequired attenuation: 18 dB (A) at 250 Hz

Solution:Diag. 1: PZ-R 200/100 Attenuator length: L = 1480 mm

Diag 2. : Effective air velocity: vef = 7 m/s Pressure drop: ∆ ptot = 17 Pa Attenuator cross-section: B x H = 2400 x 600, 1600 x 900 ili 1200 x 1200

Diag. 5: Frequency Hz 125 250 500

Flow regenerated noise dB (A) 37 32 29Atot = B x H= 1.44 m2

Tab. 9: Correction dB (A) 2 2 2

Total flow regenerated nise dB (A) 39 34 31

In each octave band noise values determined above have to be by 9 dB(A) lower than the attenuated source noise measured after the attenuator (see Figure).

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Sound attenuator

Source noisebefore attenuator

Remaining noisemeasurement point


Sound Attenuators

13



Type PZ 300/100


otpo

r ∆

p [

Pa]

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

Air

velo

city

vef [

m/s

]

Air volume rate V [m3/h] x 103 Air

Pre

ssur

e dr

op ∆

p [P

a]Width B [mm]

Number of splitters

14

Sound Attenuators

14

8. Air Flow Regenerated Noise Diagram ford/s = 200/100d/s = 300/100(based on outlet size B x H = A tot = 1 m2)

9. Air Flow Regenerated Noise Diagram ford/s = 200/200(based on outlet size B x H = A tot = 1 m2)

Air velocity vef [m/s] Air velocity vef [m/s]

So

un

d p

ow

er le

vel

[dB

]

So

un

d p

ow

er le

vel

[dB

]

10. Correction table

Correction dB (A)

Ordering Key: SplitterSplitter Attenuator

Splitter thickness

Airway width

Attenuator dimensions

Flow-exposed splitter side:- With protecting plate N- Without protecting plate O

Splitter coverings:- Glass fibre veil V- Glass fibre silk S- Reflective plate and glass fibre veil RV- Reflective plate and glass fibre silk RS- Perforated plate and glass fibre veil PV- Perforated plate and glass fibre silk PS

Designations as for attenuator

Splitter dimensions


Sound Attenuators

Round Sound Attenuators, Type PZC and PZC-J

Standard Sizes [mm]

15

Cylindrical sound attenuators, type PZC and PZC-J, are intended for use in air conditioning and ventilation systems. They are convenient for installation to suction and discharge side of axial fans, to suction side of radial fans, as well as to circular ducts.The outer casing is made of galvanised sheet steel, filled with sound absorbing material. Inner duct of the attenuator is made of perforated galvanised sheet steel, which protects

the infill from airflow erosion. Standard types: attenuator without soundabsorbing pod (type PZC) or with additional cylindrical, centrally positioned sound-absorbing pod (type PZC-J). In order to improve aerodynamic characteristics, it is advisable to mount the coned end to the flow-exposed side of the pod, what has to be specially indicated on order.Cross-section flow area of the PZC-J attenuator is for about 40% smaller than at PZC-type attenuator.

Air inlet coned end(on customer´s request)

φ d = 560

φ d = 560

Standard diameter

Flowarea

Attenuator weight (kg)

Ordering Key:Attenuator without pod Attenuator with pod

Standard size φ d = 560

Additional mark for coned end(on special request)

Standard size φ d = 560

Application

16

Sound Attenuators

16

PZC i PZC-J Technical Data

1. In

sert

ion

Lo

ss (

Att

enu

atio

n)

De

[dB

]

d [mm]F

requ

ency

Sta

ndar

dsi

ze


Sound Attenuators

17

PZC i PZC-J Technical Data

2. Air Pressure Drop and Flow Regenerated Noise Diagram

2.1 for PZC Type 2.2 for PZC-J Typest

anda

rd s

ize

φ d

stan

dard

siz

e φ

d

Sound Power Level of Regenerated Noise: LW = Lp + k [dB/m]

2.3 Correction chart

]

Air flow rate V [m3/h] x 1000 Air flow rate V [m3/h] x 1000

Reg

ener

ated

noi

se L

p [d

B/m

]

Pressure drop

Pressure drop

18

Sound Attenuators

18

Interspace Sound Attenuator, Type PZM

Interspace sound attenuators are intended for noise reduction between the rooms that are physically and acoustically connected by means of air conditioning or ventilation ducts. These sound attenuators may be applied for additional noise reduction, if, for example, main sound attenuator is insufficient. PZM attenuators are tube type attenuators made of galvanised sheet steel, containing sound-absorbing material infill. Isolation infill facing, exposed to airflow erosion, is covered by perforated galvanised sheet steel.Interspace sound attenuators are installed in two arrangement types:- In the main duct passing through all rooms, having no

lateral ducts (Fig. 1)- In lateral ducts of the main duct (Fig. 2)The first arrangement is mainly applied in smaller ventilation systems. In that system, due to different air flow rates, connection diameters of attenuators are normally different. All partial air pressure drops are summed up and therefore have to be as low as possible.Each attenuator has to achieve total sound attenuation between two rooms; therefore, very long attenuators are required. In the second installation arrangement, connection diameters are usually the same, and pressure drops are smaller (no serial summing up).

Standard Sizes [mm]

Dimensions of interspace sound attenuator, type PZM

Standardsize φ d

[mm]

80

100

125

150

160 158 260

180

200

224

250

300

315

335

78

98

123

148

178

198

222

248

298

313

333

180

200

225

250

280

300

324

350

400

415

435

φ d - 2 [mm]

φ D [mm]Lenghts L [mm]

L =

450

, 95

0, 1

450,

195

0fo

r al

l dia

met

ers

φ d

φ d

- 2

Figure 1 Figure 2

Ordering Key:

L- Attenuator lenght

Rated diameter - φ d

Application


Sound Attenuators

19

Technical Data

2. Dijagram otpora

Guideline criteria to be taken into account in sound attenuation calculations:- Basic criteria takes into account sound isolation of a partition wall between two rooms and requires that PZM has an insertion loss (attenuation) equal to or 10 dB higher in each octave than attenuation of the partition wall.- Unrecognised speech and music attenuation criterion

requires that sound level of speech or music in the room of interest has to be 10 to 15 dB lower than level of other noise corresponding to NR-curve in all octaves.- If PZM attenuator has to reduce a part of basic noise of the fan from the plant room, its insertion loss (attenuation) has to be tested for that case.

Attenuator dimensions:- Attenuator length is derived from the insertion loss(attenuation) per meter length (Diagram 1).- Inner diameter of attenuator is derived from given air flow rate and selected effective air velocity vef , and permitted pressure drop as well (Diagram 2).Air flow regenerated noise through attenuator has to be taken into account too. In each octave it has to be 10 dB lower than permitted level of sound power spectrum after the attenuator (see figure on page 8 of this register).

PZM

siz

e

Frequency [Hz]

Inse

rtio

n lo

ss [d

B]

1. Diagram - Insertion Loss per Meter Length

2. Air Pressure Drop Diagram

Effe

ctiv

e A

ir ve

loci

ty v

ef [

m/s

]

Air flow rate V [m3/h]

Air

Pre

ssur

e dr

op ∆

p [P

a/m

]

Klimaoprema d.d.Gradna 78A

HR-10430 Samobor, CROATIAPhone: + 385 1 33 62 513

Fax: + 385 1 33 62 [email protected]

Documents

6S1 Sound Attenuators