6/S1 SOUND ATTENUATORS PZ, PZC, PZM, PK. v 2.4 (en)

Transcription

1 6/S1 v 2.4 (en) SOUND ATTENUATORS PZ, PZC, PZM, PK 9

2 TABLE OF CONTENTS Rectangular attenuators - PZ... 3 Round sound attenuators - PZC Interspace sound attenuator - PZM Definition of symbols: B [m] H [m] L [m] d [m] s [m] V [m 3 /h] v [m/s] p [Pa] - Attenuator width - Attenuator height - Attenuator length - Splitter width - Splitter gap - Air flow rate - Air velocity - Pressure drop f [Hz] m L [db] W L [db] WA De [db] L pa [db(a)] - Frequency - Sound power level - Sound power level (A-weighting) - Sound attenuation - Sound pressure level (A-weighting) 3

3 RECTANGULAR ATTENUATOR For sound attenuation in ventilation ducts and ventilated areas Aerodynamically shaped sound attenuation splitter reduces drag by % (energy savings) Sound attenuation splitters are made of flame retardant material, apsorption material Splitters are constructed in three standard thicknesses: d = mm, d = mm and d = mm Rectangular sound attenuators are available in five standard cross-section dimensions: d/s = /; /; /; / and / Attenuator casing is made of galvanised steel, fitted with flanges meeting criteria given in the table on page 3 Attenuators heavier than kg are supplied in two or more sections, each single section lighter than kg L SOUND ATTENUATION SPLITTER Absorption material rock-wool, non-flammable, according to Class A2, to DIN 42, Part 1. Significant attenuation in frequency span form 63 to 8Hz. Aerodynamic splitter shape. Splitter cover (lining): Glass fibre veil (V) - Very thin protective cover on the splitter surface Reflective plates (R) - Half of each side of the splitter (alternatively centre up and centre down) is fitted with galvanised tin plates Glass silk (S) - At air velocities higher than m/s Meets standards VDI 22, Part 1 and Part 3, DIN 1946, Part 2 and Part 4 and VDI

4 Standard attenuator dimensions and weights ( no splitter lining) H 1 L Duct width B PZ / d/s = / PZ / d/s = / H 1 L Duct width B PZ / d/s = / PZ / d/s = / PZ / d/s = /

5 Standard attenuator dimensions and weights ( with splitter lining) H 1 L Duct width B PZ / d/s = / PZ / d/s = / H 1 L Duct width B PZ / d/s = / PZ / d/s = / PZ / d/s = /

6 Connecting more attenuators Sections of the attenuator are connected with built-in flanges and bolts Contact flange surfaces can be additionally fixed by reinforcement holders Prior to attenuator delivery, sections of each attenuator are assembled and disassembled in the factory. Connection along width Connection along length H d s L B Connection along height Four and eight sectional attenuator 314

7 Attenuation diagram, type PZ / De [db] f [Hz] Selection diagram H 1 brzina zraka v ef [m/s] B 4, 7 otpor p [Pa] d/s = / Width B No. of splitters količina zraka V [m 3 /h] x

8 Attenuation diagram, type PZ / De [db] f [Hz] Selection diagram H 1 B d/s = / Width B No. of splitters otpor p [Pa] brzina zraka v ef [m/s] 8 1 količina zraka V [m 3 /h] x 3 316

9 Attenuation diagram, type PZ-R / De [db] f [Hz] Example: Given: Airflow rate: V= m 3 /h Required attenuation: 24 db (A) at 2 Hz Solution: Dg 1: PZ-R / Attenuator length: L = 1 mm Dg 2: Effective air velocity v ef =, m/s Pressure drop Δ P tot = 17 Pa Attenuator cross-section B x H = 13 x or x Dg. 7: Frequency Hz 12 2 Flow regenerated noise db (A) A tot = B x H=,81 m2 Tab. 9: correction db (A) Total air flow regenerated noise db(a) 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). Sound Prigušivač attenuator zvuka Nivo Source buke noise izvora before attenuator prije prigušenja Remaining Mjesto mjerenja noise measurement point preostale buke 317

10 Attenuation diagram, type PZ-R / De [db] f [Hz] Hz 2 Hz Hz Hz Hz Lw [db] Nivo šumnosti [db] 2 Hz 12 Hz 63 Hz Hz Hz Lw nivo [db] šumnosti [db] 12 Hz 63 Hz brzina zraka v ef [m/s] brzina zraka v ef [m/s] Airflow regenerated noise diagram for d/s = / (based on outlet size B x H = A tot = 1m 2 ) Airflow regenerated noise diagram for d/s = / (based on outlet size B x H = A tot = 1m 2 ) Correction table A tot [m 2 ],2,,7 1 1,2 1, 2 Correction db (A)

11 Attenuation diagram, type PZ / De [db] f [Hz] H B d/s = / Width B No. of splitters brzina zraka v ef [m/s] 6 1 otpor p [Pa] količina zraka V [m 3 /h] x 3 319

12 Attenuation diagram, type PZ / De [db] f [Hz] Selection diagram H B d/s = / Width B No. of splitters otpor p [Pa] brzina zraka v ef [m/s] količina zraka V [m 3 /h] x

13 Attenuation diagram, type PZ-R / De [db] f [Hz] Example: Given: Airflow rate: V= m 3 /h Required attenuation: 18 db (A) at 2 Hz Solution: Dg 1: PZ-R / Attenuator length: L = 1 mm Dg 2: Effective air velocity v ef = 7 m/s Pressure drop Δ p tot = 17 Pa Attenuator cross-section B x H = 2 x or 1 x Dg. 7: Frequency Hz 12 2 Flow regenerated noise db (A) A tot = B x H=,81 m 2 Tab. 9: correction db (A) Total air flow regenerated noise db(a) 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). Sound Prigušivač attenuator zvuka Nivo Source buke noise izvora before attenuator prije prigušenja Remaining Mjesto mjerenja noise measurement point preostale buke 321

14 Attenuation diagram, type PZ / De [db] f [Hz] H 1 B d/s = / Width B No. of splitters 8 2 količina zraka V [m 3 /h] x 3 otpor Δ p [Pa] brzina zraka

15 Airflow regenerated noise diagram for d/s = /; (based on outlet size B x H = A tot = 1m 2 ) Airflow regenerated noise diagram for d/s = / (based on outlet size B x H = A tot = 1m 2 ) Hz 2Hz Hz Hz 2Hz Hz Hz Lw [db] nivo šumnosti [db] 12Hz 63Hz Hz 12Hz Lw [db] nivo šumnosti [db] 63Hz brzina zraka v ef [m/s] brzina zraka v ef [m/s] A tot [m 2 ],2,,7 1 1,2 1, 2 Correction db (A) Ordering key: Sound attenuator Splitter width / gap PZ - d / s - B x H x L Dimensions Splitter coverings: V - Glass fibre veil RS - Reflective plate and glass silk PS - Perforated plate and glass silk S - Glass silk RV - Reflective plate and glass fibre veil PV - Perforated plate and glas fibre veil - V Splitter Dimensions Designations as for attenuator PK - d x H x L - O/V 323

16 ROUND ATTENUATOR - PZC 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 Options Version with pod PZC b d p x z Ød ØD k L PZC - J b d p x z Ød ØD j k L Flow Attenuator weight Standard ød ø j øk b s area L= L= L=1 diameter [m 2 ] PZC PZC-J PZC PZC-J PZC PZC-J ødpxz 3, ,x8, ,x8 4, ,x8, ,x8, ,x12 6, ,x12 7, ,x12 8, ,x16, ,x16, ,x16 Ordering key Round attenuator J - attenuator with pod Standard size ød Attenuator length PZC - J - - L 324

17 Attenuation D e [db] Frequency [Hz] Diameter PZC PZC-J PZC PZC-J PZC PZC-J PZC PZC-J PZC PZC-J PZC PZC-J PZC PZC-J PZC PZC-J Attenuator length: L= Attenuator length: L= Attenuator length: L= p [ Pa] 8 7 p [ Pa] 8 Lp [db/m] Standard size Ød Lp [db/m] 3 Standard size Ød V [m 3 /h*m]* V [m 3 /h*m]* 32

18 INTERSPACE ATTENUATOR - PZM PZM attenuators are made of galvanised sheet steel, containing sound-absorbing material infill. Dimensions of interspace sound attenuator ØD Ød Standard size ød ød-2 ød 98 Lenghts L L L=,, Standard sizes Insertion loss per meter length prigušenje [db/m] De f frekvencija [Hz] Ordering key Interspace Sound Attenuator PZM - - Diameter ød Attenuator length 326

19 NOTES: 327