1、THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION Silencers and acoustic enclosures A Guide to selection and assessment PUBLICATION 161 Edition 2 RELEASED BY IHS. NOT FOR RESALE THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION Silencers and acoustic enclosures A Guide to selection a
2、nd assessment PUBLICATION 161 Edition 2 Copyright 2014 The Engineering Equipment and Materials Users Association. A company limited by guarantee. Registered in England. Company number 477838. ISBN 978 0 85931 206 6 Imprint reference 11-2014 Registered and Trading Address 63 Mark Lane London EC3R 7NQ
3、 Telephone: +44 (0)20 7488 0801 Fax: +44 (0)20 7488 3499 E-mail: saleseemua.org Website: www.eemua.orgEEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA ii ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION About EEMUA The Engineering Equipment an
4、d Materials Users Association is usually known by its initials, EEMUA. EEMUA is an Association established by the owners and operators of industrial assets. Any organisation that is a substantial user or substantial purchaser of engineering products is eligible to apply to become a member of EEMUA.
5、Membership is subject to the approval of Council. EEMUA aims EEMUA aims to improve the safety, environmental and operating performance of industrial facilities in the most cost-effective way, pursuing and promoting leadership in industrial asset management by sharing engineering experiences and expe
6、rtise, and by the active, enlightened promotion of the distinct interests of users of engineering products. These aims are achieved by various means, including: Providing the organisation within which networking, information sharing and collaboration among users on non-competitive technical matters
7、can take place Influencing the way written regulations are interpreted and applied in practice Promoting and presenting members views, and encouraging the application of good sound engineering practices Developing user guides, specifications, training and competency schemes Facilitating members part
8、icipation in national and international standards making Influencing relevant national and European legislation and regulation. The income and resources of EEMUA are applied solely towards the promotion of the aims of the Association. No profit is transferred by way of dividend, bonus or otherwise t
9、o members. The work of the Association is mainly carried out by members representatives on EEMUA Technical Committees, Working Groups, and Forums, supported by EEMUA staff. Incorporation, membership and other information For the purposes of conducting its business, EEMUA is incorporated in England a
10、nd Wales as a company, limited by guarantee, not having share capital. All usual aspects of company management and business administration are dealt with through the EEMUA Chief Executive, including policy implementation and leadership of the Executive team (the staff). A list of EEMUA publications
11、for sale is given at the end of this Publication. The full list is also on the Associations website, including details of on-line shopping facilities. To enquire about corporate Membership, write to askeemua.org or call +44 (0)20 7488 0801. EEMUA Publication 161: Silencers and acoustic enclosures -
12、A Guide to selection and assessment EEMUA iii ABOUT THIS PUBLICATION Legal aspects All rights, title and interest in this Publication belong to EEMUA. All rights are reserved. No part of this Publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means: ele
13、ctronic, mechanical, photocopying, recording or other, without the express prior written agreement of the EEMUA Chief Executive. Infringement of copyright is illegal and also reduces the Associations income thereby jeopardising its ability to fund the production of future publications. It has been a
14、ssumed in the preparation of this Publication that: the user ensures selection of those parts of its contents appropriate to the intended application; and that such selection and application is correctly carried out by appropriately qualified and competent persons for whose guidance this Publication
15、 has been prepared. EEMUA and the individual members of the Work Group that prepared this EEMUA Publication do not, and indeed cannot, make any representation or give any warranty or guarantee in connection with material contained herein. EEMUA and the individual members of the Work Group that prepa
16、red this EEMUA Publication expressly disclaim any liability or responsibility for damage or loss resulting from the use or reliance on this Publication. Any recommendations contained herein are based on the most authoritative information available at the time of writing and on current good engineeri
17、ng practice, but it is essential for the user to take account of pertinent subsequent developments and/or legislation. Any person who encounters an inaccuracy or ambiguity when making use of this Publication is asked to notify EEMUA without delay so that the matter may be investigated and appropriat
18、e action taken. Consultation and feedback EEMUA encourages constructive comments on this Publication from both Members of the Association and others. Comments should be sent on the standard feedback form, a copy of which is provided towards the end of this Publication. An electronic version of the f
19、eedback form is available from EEMUA - e-mail your request for a copy to askeemua.org, telephone your request to +44 (0)20 7488 0801, or download the form from the EEMUA website at www.eemua.org. Submit comments by e-mail (preferred) or post. Comments are considered by the relevant EEMUA Technical C
20、ommittees and may be incorporated in future editions of this Publication. New editions are publicised on the EEMUA website. EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA iv Contents Preface . vii Abbreviations and definitions viii 1. Introductio
21、n . 1 1.1 Scope 2 1.2 About this Edition . 2 2. Types of silencer 5 2.1 Reactive silencer . 5 2.2 Absorptive silencer 6 2.3 Reactive/absorptive silencer . 7 2.4 Helmholtz resonators 8 2.5 Diffuser silencers 8 2.6 Multiple orifice silencer 9 2.7 Air entrainment screen silencer. 10 2.8 Active noise co
22、ntrol . 11 3. Silencer applications 13 3.1 Venting 13 3.1.1 Continuous venting 13 3.1.2 Infrequent or emergency venting 14 3.2 Flares 15 3.2.1 Elevated flares 15 3.2.2 Ground flares 15 3.3 Gas turbines . 15 3.3.1 Gas generator intake . 16 3.3.2 Power turbine exhaust . 16 3.4 Internal combustion engi
23、nes 17 3.5 Compressors and blowers 17 3.5.1 Axial and centrifugal compressors . 17 3.5.2 Reciprocating compressors . 18 3.5.3 Screw compressors 18 3.5.4 Blowers 19 3.5.5 Fans 19 3.6 Ventilation . 19 3.6.1 Natural ventilation . 20 3.6.2 Forced ventilation 20 3.7 Heat exchanger fans . 20 3.8 Combustio
24、n plant 21 3.8.1 Natural draft combustion plant 21 3.8.2 Forced draft combustion plant . 22 3.9 Electric motors . 22 4. Mechanical considerations . 23 4.1 Corrosion . 23 4.2 Erosion 23 4.3 Materials for the absorptive filling . 24 4.4 Draining 24 4.5 Impermeable membrane 24 4.6 Pressure drop . 25 4.
25、7 Installation . 25 EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA v 4.8 Inspection and maintenance . 25 4.9 Temperature effects 26 4.10 Integrity 26 4.11 Vibration isolation . 26 5. Acoustic requirements . 29 5.1 Specification . 29 5.1.1 General
26、 29 5.1.2 Dynamic insertion loss . 29 5.1.3 Sound power level . 29 5.1.4 Sound pressure level . 30 5.1.5 Narrow band or tonal noise . 30 5.1.6 Details to be agreed between Purchaser and Vendor 30 5.2 Testing 31 5.2.1 Dynamic insertion loss . 31 5.2.2 Sound power level . 31 5.2.3 Sound pressure level
27、 . 32 6. Acoustic enclosures for machines 33 6.1 Application . 33 6.2 Acoustic performance 33 6.3 Materials of construction 33 6.4 Weather and corrosion protection . 33 6.5 Sound absorption filling . 33 6.6 Impervious membrane 34 6.7 Assembling and dismantling . 34 6.8 Lifting requirements 34 6.9 Pa
28、nel joints 34 6.10 Vibration isolation . 34 6.11 Access doors 34 6.12 Panic-action doors . 34 6.13 Ventilation and purging 34 6.14 Blast proofing . 35 6.15 Details to be agreed between Purchaser and Vendor 35 6.16 Preliminary noise enquiry . 39 Appendix A glossary of acoustic terms . 41 A.1 The deci
29、bel 41 A.2 Sound pressure level . 41 A.3 Sound power level 41 A.4 Frequency 42 A.5 Broadband noise . 42 A.6 Octave bands . 42 A.7 Narrow band or tonal noise 42 Appendix B Model data sheet for specifying a silencer . 43 References . 47 Bibliography and related EEMUA Publications 47 EEMUA Publications
30、 Catalogue . 49 EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA vi List of Figures Figure 1 Reactive silencer . 5 Figure 2 Rectangular absorptive silencer 6 Figure 3 Combined reactive and absorptive silencer . 7 Figure 4 Form of Helmholtz resonato
31、r 8 Figure 5 Diffuser silencer 9 Figure 6 Multi-orifice silencer 10 Figure 7 Air entrainment screen silencer 11 List of Tables Table 1 Model data sheet for acoustic enclosures - Part 1 . 36 Table 2 Model data sheet for acoustic enclosures - Part 1(continued) . 37 Table 3 Part 2: Information to be su
32、pplied by the vendor . 38 Table 4 Preliminary noise enquiry 39 EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA vii Preface Noise control measures such as silencers and enclosures are required within industrial installations to reduce noise for a v
33、ariety of reasons, including meeting health and safety work area noise limits and environmental noise criteria for community noise. It is therefore important that the acoustic properties for noise control equipment are correctly specified. Whilst specifying and meeting the acoustic properties is fun
34、damental, the choice of noise control can potentially have a major impact on mechanical issues that can affect plant operation and maintenance. This document gives guidance on the acoustic properties required for silencers and acoustic enclosures to assist in the specification of these during the de
35、sign phase and procurement process. The acoustic properties that need to be included within the specification along with the test procedures to demonstrate the criteria can be met are outlined. The mechanical issues that need to be considered within industrial installations are described. This Guide
36、 should assist those involved in specifying, supplying or procuring noise control equipment so that the correct acoustic information is obtained taking into account practical operational considerations. This will assist in ensuring that the installed plant meets the noise criteria for industrial dev
37、elopments. The previous version of this Publication was issued in 1988. The purpose of this Edition 2 is to take into account new revisions of standards and advances in acoustic technology. In particular the Section on silencer performance testing has been changed to reflect changes to the available
38、 standards. The Section on acoustic enclosures has been included within the main document, rather than as a separate supplement. EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and assessment EEMUA viii Abbreviations and definitions Approved Unless otherwise qualified
39、, means formal, written agreement by the Purchaser to a proposal by the Vendor ANSI American National Standards Institute Bara Bar (absolute pressure) BS British Standards Institute CACA cool air, cool air Cv Flow coefficient of device Cg Coefficient of isothermal compressibility dB decibel dB(A) A-
40、weighted sound pressure level Purchaser Refers the client who has placed the order for the silencer or acoustic enclosure Shall This term is used to indicate that the Purchaser/Vendor is required to take action Should This term is used to indicate that the Purchaser/Vendor is advised to take action
41、TEFC Totally Enclosed Fan Cooled Vendor Refers to the fabricator/supplier to whom the contract has been awarded Acknowledgements EEMUA acknowledges the assistance of KBR for the development of this Publication. EEMUA Publication 161: Silencers and acoustic enclosures - A Guide to selection and asses
42、sment EEMUA 1 1. Introduction Industrial installations use silencers for a wide variety of applications to reduce noise from machines and fluid-flow systems. They may range from devices small enough to hold in the hand - for use with pneumatic systems - to large installations weighing several tonnes
43、 for large steam vents in power stations. In all these applications, the essential feature of a silencer is that it allows the flow of a gas and reduces the transmission of acoustic energy; it may therefore be distinguished from an acoustic enclosure, where gas flow, say, for cooling or purging, is
44、a secondary feature. The primary purpose of a silencer or acoustic enclosure is to reduce noise to some required level, so the correct specification of its acoustic properties is the key aspect of its purchase. Other aspects, however, can be equally important; for example, operational life and safet
45、y features. For silencers the possible effect on the fluid flow and its compatibility with the fluid and operation of the plant is important. Maintenance issues also need to be considered. If a silencer is expensive, or if its replacement causes an expensive shutdown of the plant, the operating life
46、 will be important. This will require careful specification of the materials of construction, its weather protection in outdoor operation, and its ease of replacement. If it is associated with expensive equipment, the effect of damage to the equipment caused by any disintegration of the silencer sho
47、uld be considered. So a careful specification of the silencer construction can be as important as its acoustic specification. A silencer or acoustic enclosure may be required to: reduce the noise level inside a plant, for hearing conservation; improve speech communication within work areas; meet env
48、ironmental noise criteria or to avoid annoyance to neighbours; and/or to meet noise criteria within accommodation spaces. In any of these cases, the noise control equipment will be required to reduce the noise level in dB(A) at one or more locations. If the noise source contains tonal components, th
49、ese will require additional consideration so that they are reduced to a level where they are masked by the broadband noise. This is discussed in Section 5.1.5 and it means that the acoustic properties of silencers need to be specified in more detail. There are various types of silencers and it is useful to have a basic understanding of how they operate and the typical applications in which they are used, so that the appropriate type can be selected for a particular application. Chapter 2 of this Guide gives a brief description of the different basi
