Practical Guide to Noise and Vibration Control, …

1 A Practical Guide toNoise and Vibration Controlfor HVAC Systems American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written first edition of this book was prepared under ASHRAE Research ProjectRP-526, sponsored by TC , Sound and Vibration . This revised and updatedsecond edition was prepared under the direction of TC THE AUTHORMark E. Schaffer, 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 , Sound and Vibration , and a co-presenter of the ASHRAE Professional Development Seminar on HVAC Noise andvibration control .

2 He has participated in the development of ASHRAE Handbookchapters in that area. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written Society of Heating, Refrigeratingand Air-Conditioning Engineers, Practical Guide toNoise and Vibration Controlfor HVAC SystemsSECOND EDITIONMark E. SchafferRP-526 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written 978-1-931862-77-6 Library of Congress control Number: 2005926749 1991, 2005 American Society of Heating, Refrigeratingand Air-Conditioning Engineers, Tullie Circle, , GA rights edition 1991 Second edition 2005 Printed in the United States of AmericaCover design by Tracy 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 herein.

3 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, 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 part of this book may be reproduced without permission in writing from ASHRAE, exceptby a reviewer who may quote brief 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 means electronic, photocopying, recording, or other withoutpermission in writing from STAFFSPECIAL PUBLICATIONSM ildred GeshwilerEditorErin HowardAssociate EditorChristina HelmsAssociate EditorMichshell PhillipsSecretaryPUBLISHING SERVICESD avid SoltisManagerJayne JacksonProduction AssistantPUBLISHERW.

4 Stephen Comstock American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written 1 General Design Guidelines1 Chapter 2 Airside Equipment25 Chapter 3 Waterside Equipment73 Chapter 4 Packaged and Unitary Equipment89 Chapter 5 Vibration Isolation101 Chapter 6 Specifications117 Chapter 7 Construction Phase Tasks125 Chapter 8 Troubleshooting Noise and Vibration Complaints143 Appendix A Some Basics of HVAC Acoustics167 Appendix B Acoustical Rating Systems and Criteria177 Appendix C Measuring HVAC System Noise191 Appendix D Using Manufacturers Sound Data197 Appendix E Definitions and Abbreviations201 Appendix F Addresses of Agencies and Associations207 Appendix G Bibliography and Selected References209 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

5 ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written of an air-handling unit room with several acoustical of an air-handling unit room with optimal acoustical 11-1 Guideline for duct chase, shaft, and enclosure comparison of various building core area for the preliminary selection of mechanical room mechanical penthouse equipment air path used for sound attenuation at an equipment room ventilation Noise control for mechanical Noise control using an auxiliary views through two types of floating floor transmission at perimeter mechanical conduit routing into a mechanical lagging for Noise of rumbly and quieter parallel fan for a basement built-up fan duct silencer arrangement at vane-axial American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

6 ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written and refracted equipment sound at a building support of rooftop equipment for Vibration for mechanical room wall and pipe penetrations through view of return air shaft with supply duct takeoffs obstructing return comparison of several duct chase, shaft, and enclosure typical duct control duct 22-1 Inlet and discharge octave band LW values for a 36 in. plenum power level comparison for three types of centrifugal for centrifugal fan fan airflow view into a mixed flow fan sound power level for ducted axial flow fan for unducted axial flow fan side of a direct-drive plenum side of a belt-drive plenum roof ventilators (mushroom fans) mounted on intake duct silencers and roof type exhaust fan on Vibration -isolated roof octave band LW comparison for three propeller fan with a 12-socket aluminum hub and plastic propeller fan with backswept airfoil hood for propeller fan Noise isolation suspension for propeller and quiet installations of ceiling-mounted exhaust clearance at AHU and cabinet fan AHU with supply ducts attached to the top of discharge sketch of a plenum fan air-handling American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

7 ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written Practical Guide to Noise and Vibration control for HVAC Systems2-22 Guidelines for VAV unit air valve and its Noise flow inlet duct connection to a supply air ceiling inlet duct connection to a supply air ceiling effect of installing a damper behind a for lined and unlined sheet metal transmission loss for three types of sheet metal for minimizing regenerated Noise in for minimizing regenerated Noise in for minimizing regenerated Noise in transitions and for minimizing regenerated Noise in duct attenuation for various duct liner speaking tube (cross-talk) of rectangular elbows with and without turning vanes (lined and unlined).572-36 Attenuation of rectangular and radius elbows (lined and unlined).

8 572-37 Flexible duct with spunbond nylon inner view into a dissipative duct view of a duct silencer with film-lined view of a reactive ( packless, no-fill, or no-media ) duct view of an elbow duct attenuation of duct silencers and lined insertion loss of dissipative, film-lined, and reactive duct for duct silencer placement near fans and duct silencer placement near a mechanical room guidelines for sound-attenuating plenum louver transmission loss of acoustical and weatherproof louver in a parking garage ventilation for fan selection in a VAV inlet vanes obstruct frequency American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written 33-1 Water-cooled screw chiller with several Noise and Vibration control LW values for a 250-ton air-cooled chiller with and without factory Noise reduction octave band LP values at 50 ft from the air inlet side of three types of 800-ton cooling octave band LP values for cooling towers of the same fabrication series but with fans of different of standard cooling tower induced-draft of an induced-draft fan with wide-chord blades.

9 This fan type can be as much as 12 dBA quieter than a standard fan of the same octave band LP values for cooling towers with standard and wide-chord fan tower basin with free-falling condenser basin silencers installed a few inches above the Noise control barrier view of a sample of a sound-absorbing, outdoor Noise barrier control sequence for a two-cell cooling impeller sizing guideline for minimizing the strength of the blade passage frequency installation of an end-suction installation of an inline isolation for piping installation of horizontal isolated pipe penetrations for sound 44-1 Very noisy rooftop unit noisy rooftop unit quiet rooftop unit rooftop unit for suspended heat pump for floor-mounted heat condensing unit Noise American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( ).

10 For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE s prior written Practical Guide to Noise and Vibration control for HVAC Systems4-8 Guidelines for fan coil unit for Vibration isolation of split systems984-10 Indoor fan coil section of a ductless split condensing unit typically used with ductless split systems can also be used with ducted fan coil radiator for engine-generator sets can be quiet with an oversized, variable-speed cooling 55-1 Elastomeric or compressed fiberglass isolation rated elastomeric types of spring floor hanger types of spring floor mounts with standby isolators ( air bags ) supporting a rooftop air-cooled floor thrust and flanged flexible pipe (pump) metal pump connector is not an effective Vibration mount spring isolator under a height-saving bracket with a separate seismic mounted on combination 77-1 Overhead plan views of AHU rooms showing the effects of a duct installed dual-duct variable air volume of large duct elbow verifying screw attachment of turning debris short-circuiting isolator spring free-standing floor floor mount isolator whose shipping shims have not been spring hanger installation with hanger rod touching the hanger American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.