1、A Practical Guide toNoise and Vibration Controlfor HVAC SystemsThe first edition of this book was prepared under ASHRAE Research ProjectRP-526, sponsored by TC 2.6, Sound and Vibration. This revised and updatedsecond edition was prepared under the direction of TC 2.6.ABOUT THE AUTHORMark E. Schaffer
2、, PE, Member ASHRAE, is president of Schaffer Acoustics Inc.,a southern California acoustical consulting and testing firm. He has been an acous-tical consultant for 29 years and an HVAC subcontractor for 5 years. He is an activemember of ASHRAE Technical Committee 2.6, Sound and Vibration, and a co-
3、presenter of the ASHRAE Professional Development Seminar on HVAC noise andvibration control. He has participated in the development of ASHRAE Handbookchapters in that area.American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.A Practical Guide toNoise and Vibration Controlfor
4、 HVAC SystemsSECOND EDITIONMark E. SchafferRP-526ISBN 1-931862-77-XLibrary of Congress Control Number: 20059267491991, 2005 American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.1791 Tullie Circle, N.E.Atlanta, GA 30329www.ashrae.orgAll rights reserved.First edition 1991Secon
5、d edition 2005Printed in the United States of AmericaCover design by Tracy Becker.ASHRAE has compiled this publication with care, but ASHRAE has not investigated, andASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure,design, or the like that may be described
6、 herein. The appearance of any technical data or edito-rial material in this publication does not constitute endorsement, warranty, or guaranty byASHRAE of any product, service, process, procedure, design, or the like. ASHRAE does notwarrant that the information in the publication is free of errors,
7、 and ASHRAE does not neces-sarily agree with any statement or opinion in this publication. The entire risk of the use of anyinformation in this publication is assumed by the user.No part of this book may be reproduced without permission in writing from ASHRAE, exceptby a reviewer who may quote brief
8、 passages or reproduce illustrations in a review with appro-priate credit; nor may any part of this book be reproduced, stored in a retrieval system, or trans-mitted in any way or by any meanselectronic, photocopying, recording, or otherwithoutpermission in writing from ASHRAE.ASHRAE STAFFSPECIAL PU
9、BLICATIONSMildred GeshwilerEditorErin HowardAssociate EditorChristina HelmsAssociate EditorMichshell PhillipsSecretaryPUBLISHING SERVICESDavid SoltisManagerJayne JacksonProduction AssistantPUBLISHERW. Stephen ComstockContentsPreface xvAcknowledgments xviiIntroduction xixChapter 1General Design Guide
10、lines 1Chapter 2Airside Equipment 25Chapter 3Waterside Equipment 73Chapter 4Packaged and Unitary Equipment 89Chapter 5Vibration Isolation 101Chapter 6Specifications 117Chapter 7Construction Phase Tasks 125Chapter 8Troubleshooting Noise and Vibration Complaints 143Appendix ASome Basics of HVAC Acoust
11、ics 167Appendix BAcoustical Rating Systems and Criteria 177Appendix CMeasuring HVAC System Noise 191Appendix DUsing Manufacturers Sound Data 197Appendix EDefinitions and Abbreviations 201Appendix FAddresses of Agencies and Associations 207Appendix GBibliography and Selected References 209Illustratio
12、nsFIGURESIntroductionA Example of an air-handling unit room with several acoustical problems. xxB Example of an air-handling unit room with optimal acoustical features. xxiiChapter 11-1 Guideline for duct chase, shaft, and enclosure sizing. 41-2 Acoustical comparison of various building core area la
13、youts. 51-3 Guidelines for the preliminary selection of mechanical room walls. 61-4 Sample mechanical penthouse equipment layout. 71-5 Labyrinth air path used for sound attenuation at an equipment room ventilation opening. 101-6 Upward noise control for mechanical rooms. 101-7 Downward noise control
14、 using an auxiliary ceiling. 111-8 Section views through two types of floating floor assemblies. 121-9 Sound transmission at perimeter mechanical rooms. 121-10 Electrical conduit routing into a mechanical room. 131-11 Pipe lagging for noise control. 141-12 Examples of rumbly and quieter parallel fan
15、 installations. 151-13 Guidelines for a basement built-up fan system. 161-14 Typical duct silencer arrangement at vane-axial fan. 17Illustrations1-15 Reflected and refracted equipment sound at a building perimeter. 181-16 Structural support of rooftop equipment for vibration control. 191-17 Guidelin
16、es for mechanical room wall selection. 201-18 Duct and pipe penetrations through walls. 211-19 Plan view of return air shaft with supply duct takeoffs obstructing return airflow. 221-20 Acoustical comparison of several duct chase, shaft, and enclosure constructions. 231-21 Two typical duct laggings.
17、 241-22 Noise control duct enclosure. 24Chapter 22-1 Inlet and discharge octave band LWvalues for a 36 in. plenum fan. 272-2 Sound power level comparison for three types of centrifugal fans. 282-3 Guidelines for centrifugal fan installations. 292-4 Inline fan airflow patterns. 302-5 Cutaway view int
18、o a mixed flow fan. 312-6 Inline fan sound power level comparison. 312-7 Guidelines for ducted axial flow fan installations. 322-8 Guidelines for unducted axial flow fan installations. 332-9 Inlet side of a direct-drive plenum fan. 342-10 Discharge side of a belt-drive plenum fan. 342-11 Power roof
19、ventilators (mushroom fans) mounted on intake duct silencers and roof curbs. 352-12 Mushroom type exhaust fan on vibration-isolated roof curb. 362-13 Inlet octave band LWcomparison for three propeller fans. 372-14 Propeller fan with a 12-socket aluminum hub and plastic blades. 372-15 Ultra-low-noise
20、 propeller fan with backswept airfoil blades. 382-16 Lined hood for propeller fan noise control. 382-17 Vibration isolation suspension for propeller fans. 392-18 Noisy and quiet installations of ceiling-mounted exhaust fans. 392-19 Minimum clearance at AHU and cabinet fan inlet. 412-20 Plenum AHU wi
21、th supply ducts attached to the top of discharge plenum. 422-21 Cutaway sketch of a plenum fan air-handling unit. 42A Practical Guide to Noise and Vibration Control for HVAC Systems2-22 Guidelines for VAV unit installation. 432-23 Laboratory air valve and its “noise flow” directions. 452-24 Good inl
22、et duct connection to a supply air ceiling diffuser. 472-25 Poor inlet duct connection to a supply air ceiling diffuser. 472-26 The effect of installing a damper behind a grille. 482-27 Attenuation for lined and unlined sheet metal ductwork. 492-28 Breakout transmission loss for three types of sheet
23、 metal ductwork. 502-29 Guidelines for minimizing regenerated noise in elbows. 522-30 Guidelines for minimizing regenerated noise in takeoffs. 522-31 Guidelines for minimizing regenerated noise in transitions and offsets. 532-32 Guidelines for minimizing regenerated noise in duct tees. 532-33 In-duc
24、t attenuation for various duct liner thicknesses. 542-34 The speaking tube (cross-talk) problem. 552-35 Attenuation of rectangular elbows with and without turning vanes (lined and unlined). 572-36 Attenuation of rectangular and radius elbows (lined and unlined). 572-37 Flexible duct with spunbond ny
25、lon inner liner. 582-38 Cutaway view into a dissipative duct silencer. 592-39 Cutaway view of a duct silencer with film-lined baffles. 592-40 Cutaway view of a reactive (“packless,” “no-fill,” or “no-media”) duct silencer. 612-41 Cutaway view of an elbow duct silencer. 612-42 In-duct attenuation of
26、duct silencers and lined ductwork. 622-43 Comparative insertion loss of dissipative, film-lined, and reactive duct silencers. 622-44 Guidelines for duct silencer placement near fans and duct fittings. 632-45 Duct silencer placement near a mechanical room wall. 642-46 General guidelines for sound-att
27、enuating plenum design. 662-47 Acoustical louver cutaway. 662-48 Sound transmission loss of acoustical and weatherproof louvers. 672-49 Acoustical louver in a parking garage ventilation shaft. 672-50 Basis for fan selection in a VAV system. 682-51 Nested inlet vanes obstruct airflow. 702-52 Variable
28、 frequency drive. 70IllustrationsChapter 33-1 Water-cooled screw chiller with several noise and vibration control treatments. 743-2 ARI-370 LWvalues for a 250-ton air-cooled chiller with and without factory noise reduction options. 753-3 ATC-128 octave band LPvalues at 50 ft from the air inlet side
29、of three types of 800-ton cooling towers. 763-4 ATC-128 octave band LPvalues for cooling towers of the same fabrication series but with fans of different diameters. 773-5 View of “standard” cooling tower induced-draft fan. 783-6 View of an induced-draft fan with wide-chord blades. This fan type can
30、be as much as 12 dBA quieter than a “standard” fan of the same diameter. 783-7 ATC-128 octave band LPvalues for cooling towers with “standard” and wide-chord fan blades. 793-8 Cooling tower basin with free-falling condenser water. 803-9 Water basin silencers installed a few inches above the basin. 8
31、03-10 Outdoor noise control barrier installation. 813-11 Close-up view of a sample of a sound-absorbing, outdoor noise barrier panel. 813-12 Low-noise control sequence for a two-cell cooling tower. 823-13 Pump impeller sizing guideline for minimizing the strength of the blade passage frequency tone.
32、 833-14 Proper installation of an end-suction pump. 843-15 Proper installation of an inline pump. 853-16 Vibration isolation for piping riser. 873-17 Correct installation of horizontal isolated piping. 873-18 Sealing pipe penetrations for sound isolation. 88Chapter 44-1 Very noisy rooftop unit insta
33、llation. 904-2 Moderately noisy rooftop unit installation. 904-3 Moderately quiet rooftop unit installation. 914-4 Quietest rooftop unit installation. 914-5 Guidelines for suspended heat pump units. 944-6 Guidelines for floor-mounted heat pumps. 944-7 Small condensing unit noise control. 96A Practic
34、al Guide to Noise and Vibration Control for HVAC Systems4-8 Guidelines for fan coil unit installations. 974-9 Guidelines for vibration isolation of split systems 984-10 Indoor fan coil section of a ductless split system. 984-11 Outdoor condensing unit typically used with ductless split systems can a
35、lso be used with ducted fan coil units. 994-12 Remote radiator for engine-generator sets can be quiet with an oversized, variable-speed cooling fan. 100Chapter 55-1 Elastomeric pads. 1065-2 Elastomeric or compressed fiberglass isolation mounts. 1075-3 Seismically rated elastomeric mounts. 1085-4 Two
36、 types of spring floor mounts. 1085-5 Spring hanger installation. 1095-6 Two types of spring floor mounts with standby restraints. 1105-7 Pneumatic isolators (“air bags”) supporting a rooftop air-cooled chiller. 1115-8 Cast-metal floor mount. 1115-9 Fan thrust restraint. 1125-10 Threaded and flanged
37、 flexible pipe (pump) connectors. 1135-11 Braided metal pump connector is not an effective vibration isolator. 1135-12 Floor mount spring isolator under a height-saving bracket with a separate seismic restraint. 1145-13 Pump mounted on combination isolator/restraint. 115Chapter 77-1 Overhead plan vi
38、ews of AHU rooms showing the effects of a duct offset. 1327-2 Properly installed dual-duct variable air volume unit. 1357-3 Cheek of large duct elbow verifying screw attachment of turning vanes. 1367-4 Conduit debris short-circuiting isolator effectiveness. 1377-5 Overloaded spring hanger. 1387-6 Ov
39、erloaded free-standing floor mount. 1387-7 Short-circuited floor mount isolator whose shipping shims have not been removed. 1397-8 Faulty spring hanger installation with hanger rod touching the hanger box. 139Illustrations7-9 Taut outdoor “flexible“ conduit forms a vibration “short-circuit” at cooli
40、ng tower. 1417-10 Pipe risers without vibration isolation. 141Chapter 88-1 Frequency ranges of the most likely sources of common acoustical complaints. 1448-2 Example of poor fan discharge duct design. 1508-3 An installation with poor discharge duct system aerodynamics. 1518-4 Restrained spring isol
41、ator with a “short circuit” between its baseplate and equipment mounting plate. 1558-5 View into the fan section of a rooftop unit. 1568-6 Excellent rooftop package unit installation. 1568-7 Improperly installed fan-powered variable air volume unit. 1578-8 Proper installation of an indoor self-conta
42、ined packaged HVAC unit. 1578-9 Closely spaced circular duct fittings produce turbulence and noise. 1588-10 Closely spaced rectangular duct fittings produce turbulence and noise. 1588-11 Improper duct transition at fan inlet. 1598-12 Vane-axial fan intakes too close to wall. 1598-13 Duct split using
43、 radius elbows. 1608-14 Faulty installation of a large equipment isolator with stanchion restraints. 1608-15 Proper installation of a large equipment isolator with stanchion restraints. 1618-16 Braided metal pump connectors do not provide significant vibration isolation. 1618-17 Neoprene pump connec
44、tors provide better isolation of pump vibration from attached piping. 1628-18 Incomplete vibration isolation at cooling tower. 1628-19 Taut “flexible“ conduit forms a vibration short-circuit at vane-axial fan. 1638-20 Correctly installed flexible conduit between electrical disconnect and motor. 1638
45、-21 View of pipe penetration from below roof. 1648-22 Non-isolated pipe penetration. 1648-23 Improperly placed neoprene hanger. 165Appendix AA-1 Airborne and structure-borne sound transmission. 168A-2 Airborne and structure-borne sound transmission from equipment. 169A Practical Guide to Noise and V
46、ibration Control for HVAC SystemsA-3 Chart for adding decibel values. 170A-4 Everyday sound sourcestheir frequencies and wavelengths. 171A-5 Frequencies at which various types of HVAC equipment generally control their sound spectra. 172A-6 Sound pressure levels of some everyday activities. 173Append
47、ix BB-1 Frequency weighting curves. 178B-2 Blank RC chart. 180B-3 Blank RC mark II chart. 181B-4 Blank NC chart. 183B-5 Octave band spectrum rated at NC-45. 184B-6 Blank NCB chart. 185B-7 Quality of speech communication in background noise. 189Appendix CC-1 Sound level meter. 192C-2 Sound measuremen
48、t plan. 193C-3 Blank sound measurement data sheet. 194C-4 Completed sound measurement data sheet. 195TABLESChapter 11-1 Maximum Mid-Span Deflections for Above-Grade Structures that Support Vibration-Isolated HVAC Equipment 71-2 Selection Guidelines for Slabs Separating Mechanical Equipment Rooms fro
49、m Noise-Sensitive Occupied Spaces 9Chapter 22-1 Suggested Maximum Airflow Velocities for Various Ductwork Installations 512-2 Suggested Maximum Airflow Velocities in Elbows for Rectangular Ductwork 512-3 Acoustical Characteristics of the Various Types of Ductwork 58IllustrationsChapter 33-1 Maximum Recommended Waterflow Rates 86Chapter 55-1 Vibration Isolation Selection Guide 102Chapter 77-1 Common Value Engineering Proposals and Their Potential Acoustical Impacts 1267-2 Procedure for Converting from A-Weighted LWValues to Unweighted LWValues 127Appendix AA-1 Octave Band Ce
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