IAC DUCT SILENCERS

1 IAC DUCT SILENCERSTABLE OF CONTENTSIAC: MAKING THE WORLD A QUIETER PLACEQ uiet-Duct Ultra SILENCERS .. 2 IAC America s Laboratory .. 2 Milestones in Laboratory Testing .. 3 Silencer Performance .. 4 Forward and Reverse Flow .. 4 Dynamics of Duct Silencer Design .. 4 Silencer Applications .. 5 Passive Silencer Design .. 6 Information on Silencer Specification .. 6 Locating SILENCERS in Relation to Other Components .. 7 Guidelines for Locating SilencersDucted Centrifugal Fans .. 8 Ducted 50% Hub-Vane Axial Fans .. 8 Elbows (Without Turning Vanes) .. 8 Elbows (With Turning Vanes) .. 8 Transitions .. 9 Coils and Filters .. 9 Cooling Towers and Condensers .. 9At System Entrance or Exit .. 9 Reducing Pressure Drop Factors .. 9 Operation and Maintenance.

2 10 Quiet-Duct Ultra /LowULS1 .. 11 ULS2 .. 13 ULS3 .. 15 ULM1 .. 17 ULM2 .. 19 ULM3 .. 21 ULL 1 .. 23 ULL2 .. 25 ULL3 .. 27 Quiet-Duct Ultra /GreenUGLFS .. 29 UGLFM .. 31 UGLFL .. 33 UGS .. 35 UGMS.. 37 UGML .. 39 UGL.. 41 Quiet-Duct Ultra /ZAPDZ6A .. 43Z6B .. 44Z6C .. 45Z6D .. 46Z6E .. 47Z9A .. 48Z9B .. 49Z9C .. 50Z9D .. 51Z9E .. 52Z12A .. 53Z12B .. 54Z12C.. 55Z12D .. 56 Quiet-Duct Commercial SeriesLFS .. 57 LFM .. 59S .. 61ES .. 63MS .. 65 LFL.. 67ML .. 69L.. 71 Quiet-Duct Clean Flow SilencersHFLS .. 73 HLFM .. 75HS .. 77 HMS .. 79 HLFL .. 81 HML .. 83HL .. 85 Quiet-Duct Conic Flow FCS .. 87 FCL .. 89CS .. 91CL .. 93NS .. 95NL .. 97D-Duct DiffuserD-Duct.. 99 Ultra-Pals PacklessXM.. 101XL .. 103KL .. 105KM .. 107 TXS /TXL .. 109 TXLB .. 111 Quiet-Duct Elbow SilencersELB.

3 113 ELBM .. 114 Making the World a Quieter PlaceTMwith FORWARD andREVERSE FLOWAERO-ACOUSTIC RATING CERTIFIED in accordance with ASTM E 477 andISO 7235and BRITISH STANDARD 4718 Copyright 2006, IAC AmericaQUIET-DUCTSILENCERSENGINEERED NOISECONTROL FORAIR-HANDLING SYSTEMSIAC SILENCERS : LABORATORY TESTED AND FIELD PROVEN2 IAC: MAKING THE WORLD A QUIETER PLACE IAC America offers the broadestrange of SILENCERS in the additions within this manualinclude the Modular ElbowSilencer and the new Quiet-DuctUltra Series. Performance data forthese SILENCERS is based onNVLAP-accredited laboratory testsconducted in strict accordancewith ASTM E477-99 The ELB Modular Elbow Silencerfeatures the capability to both nestand stack elbow silencer modulesso the size is scalable while aero-dynamic and acoustic performanceare maintained.

4 The silencer iscost-effective and can acceptadded acoustic extension Quiet-Duct Ultra /Low line ofsilencers offers the industry s firstpublished and guaranteed per-formance data in the Hz full-octave-band center tests were conducted usingscale modeling developed by IACA merica in cooperation with Ingard, co-author ofTheoretical Quiet-Duct Ultra /Green linewas developed in response to thetrend for environmentally friendlybuilding products. This 100% envi-ronmentally friendly attenuationsolution uses recycled acoustic fillmaterial and delivers performancethat meets or exceeds that of astandard Quiet-Duct Quiet-Duct Ultra /ZAPD linewas designed for applications inwhich acoustic attenuation isrequired and no allowance can bemade for pressure loss.

5 A Zero-Added-Pressure-Drop silencer isideal for high velocity systems orsystems that have little or no roomfor additional pressure wind tunnel and reverberation room combined, measure more than 160 ft. ( ) long. SILENCERS as large as 50 in.(1524mm) in diameter and 120 in. (3048mm)in length have been tested in IAC America'saero-acoustic Removable hatch-in roof for testingsilencers up to 10 ft. x 10 ft. ( x ) cross section2. 25,000 cfm (42,480m3/hr) vane-axial fan3. Systemic silencer4. Plenum with loudspeaker and flow diffuser5. Test unit pitot tube ports6. Super-Noise-Lock housing7. Test silencer8. 10,000 ft3(283m3) reverberation receiv-ing room9. 3,000 ft3(85m3) reverberation source room10. 3 in. (76mm) impedance tube11. 24 in. x 24 in.

6 (610mm x 610mm) anechoic wedge impedance tunnel12. 14 ft. x 9 ft. ( x ) test frame for transmission loss testsIAC AMERICA'S NVLAP-RATED LABORATORYG iven today's highly specialized markets, it is essential that an engineering and manufacturing organization operate its own develop-ment and test facilities to advance the existing technology and assure the quality of its America's labs are accredited fornine tests under the National Instituteof Standards and Technology NationalVoluntary Laboratory AccreditationProgram (NVLAP). IAC's research and development team continuouslydesigns new products and reengi-neers existing products to addressunique noise-control IAC laboratory provided a majorimpetus for the ASTM standardmethod of testing (E477-99) for pre-fabricated SILENCERS .

7 All IAC silencersare tested in accordance with applica-ble portions of the ASTM, British, andInternational Industry Standards. 1458910233121167 IAC: MAKING THE WORLD A QUIETER PLACE3 IAC America's aero-acoustic researchcenter permits forward- and reverse-flow dynamic insertion loss, self-noise,and pressure drop rating of silencersand other elements in closed-loopwind tunnels and other facilities. Dualreverberation rooms permit testing ofsystem components or assembled airhandling assure consistency, production linesilencers are periodically tested in lAC'saero-acoustic laboratory. This practice ofquality control performance testing ensuresthat all SILENCERS exhibit cataloguedDynamic Insertion Loss (DIL), Self-Noise(SN), and Pressure Drop PerformanceData. IAC always guarantees the in-fieldperformance of the they are laboratory developedand tested under controlled conditions,all of IAC's duct SILENCERS provideeffective, predictable noise are manufactured to specificmetal tolerances and with controlledacoustic infill flow resistances toachieve consistent IN LABORATORY TESTING AT IAC19 6 3 IAC builds the first full-sized dynamic duct-to-reverberant room test facility.

8 19 6 5 IAC offers duct SILENCERS accurately rated foracoustic performance with air flowing through them. IAC introduces the terms Dynamic Insertion Loss (DIL) and Self Noise (SN). 1972 IAC confirms the in-field performance of its first product developed with adds testing in the reverse flow mode. 1974 The laboratory is moved to IAC America's current facility, equipped with a controllable-pitch, vane-axial fan, and made part of a closed-loop 81 A series of new vane-axial fan diffuser SILENCERS isdeveloped with complete aerodynamic andacoustic ratings. 1984 IAC develops a new low-frequency resonatorsilencer with substantial sound attenuation below90 Hz. 1986LF low-frequency and tubular packless lines ofsilencers are 91 IAC achieves significant improvement in techniques for predicting low-frequency performance of power flowsplitter standard SILENCERS are retested for quality controland to support domestic and overseas accreditation maintained for six standard testing 97 New Sentry Quiet-Duct TLS and RFS SILENCERS meetSTC ratings of critical environments and offer the addedadvantage of RF shielding.

9 2003 IAC s new Quiet-Elbow modular system enables silencerbanks to be economically constructed from standard-sizeelbow modules while ensuring consistency and repeata-bility of acoustic and aerodynamic The IAC Aero-Acoustic Laboratory begins offering third-party testing services. 2005 Quiet-Duct Ultra /Low SILENCERS introduced. Quiet-Duct Ultra /Green SILENCERS offer 100% environ-mentally friendly attenuation Ultra /ZAPD SILENCERS are : LEADERSHIP IN SILENCER DEVELOPMENT AND TECHNOLOGY4 IAC: MAKING THE WORLD A QUIETER PLACE PERFORMANCE: DUCT LINING A question frequently asked by ourcustomers is whether duct lining alonecan provide sufficient attenuation fromnoise handling equipment. In mostcases the answer is no. As an example based on the guide-lines from the 1999 ASHRAEF undamentals Handbook, in the 250Hz octave band, an 18 in.

10 X 54 would require 57 feet of one-inch-thick, , surface-coated, duct-liner material to achieveas much insertion loss ( 32 dB) asone five-foot-long IAC 5 LFS the lower frequencies, such as 125Hz, even greater lengths of duct liningwould be required to achieve the 10 -20 dB insertion loss typically achiev-able by many of the broad range ofIAC SILENCERS including the LFS series. DYNAMICS OF DUCTSILENCER DESIGNP roper structural design assures long,trouble-free life. The attributes of a typical Quiet-Duct Silencer include: 1. Die-formed, single-piece splitterconstruction Shell-noise radiation minimized bydouble-skin or splitter constructionin most Acoustic baffles designed for maximum attenuation at low frequencies, the toughest job of all. 4. Straight-through air passagesdesigned for maximum air handlingat minimum pressure Solid, rounded noses that increasenoise Bell-mouth entrance and exit tominimize turbulence, pressure dropand self No protruding fastener heads tocause turbulence or Solid air-impingement surfaces and self-cleaning air passages to minimize dirt Acoustic fill protected against erosion by perforated metal AND REVERSE FLOWIn 1972, lAC developed silencerDynamic lnsertion Loss and Self-Noiseratings both under Forward Flow (+)and Reverse Flow (-)