AWWA M14-2015 Backflow Prevention and Cross-Connection Control Recommended Practices (Fourth Edition).pdf

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1、Manual of Water Supply PracticesM14Ideal crop marks Ideal crop marksFourth EditionM14Backflow Prevention and Cross-Connection Control: Recommended Practices,FourthEd.M14Backflow Prevention and Cross-Connection Control Recommended Practices1P1M 30014-4E (12/14) IWDedicated to the worlds most importan

2、t resource, AWWA sets the standard for water knowledge, management, and informed public policy. AWWA members provide solutions to improve public health, protect the environment, strengthen the economy, and enhance our quality of life.www.awwa.orgcross-connection is an actual or potential connection

3、between any part of a potable water system and any other environment that contains other substances that would allow such substances to enter the potable water system. Cross-connection control programs are intended to reduce the risk of contamination or pollution of the public water system. This fou

4、rth edition of AWWA Manual M14, Backflow Prevention and Cross-Connection Control: Recommended Practices, provides both technical and general guidance on the recom-mended procedures and practices for developing, operating, and maintaining a cross-connection control and backflow prevention program. Th

5、is edition includes a new chapter on conducting a cross-connection control survey and expands the discussions on assessing the risks and preventing backflow. A greatly expanded appendix details how to test most backflow prevention devices. Other issues covered include backflow prevention principles,

6、 assembly, application, installation, and maintenance; health and legal concerns; and detailed information on potential and real hazards. This manual is intended for use by all professionals charged with protecting the public water supply with proper backflow prevention and cross-connection control

7、programs.Fourth EditionManual of Water Supply PracticesM14Backflow Prevention and Cross-Connection Control Recommended PracticesCopyright 2015 American Water Works Association. All Rights Reserved.Manual of Water Supply PracticesM14, Fourth EditionBackflow Prevention and Cross-Connection Control: Re

8、commended PracticesCopyright 1973, 1989, 2004, 2015 American Water Works AssociationAll rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information or retrieval system, except

9、in the form of brief excerpts or quotations for review purposes, without the written permission of the publisher.DisclaimerThe authors, contributors, editors, and publisher do not assume responsibility for the validity of the content or any consequences of their use. In no event will AWWA be liable

10、for direct, indirect, special, incidental, or consequential damages arising out of the use of information presented in this book. In particular, AWWA will not be responsible for any costs, including, but not limited to, those incurred as a result of lost revenue. In no event shall AWWAs liability ex

11、ceed the amount paid for the purchase of this book. If you find errors in this manual, please email booksawwa.org. Possible errata will be posted at www. awwa.org/resources-tools/resource-development-groups/manuals-program.aspx.Project Manager/Senior Technical Editor: Melissa Valentine Senior Manual

12、s Specialist: Molly BeachSenior Production Editor: Cheryl ArmstrongLibrary of Congress Cataloging-in-Publication DataAsay, Stuart F., author.Backflow prevention and cross connection control : recommended practices / Stuart F. Asay. - 4th edition.pages cm. - (Manual of water supply practices ; M14)Re

13、vision of: Recommended practice for backflow prevention and cross-connection control, 3rd ed., 2004.Includes bibliographical references and index.ISBN 978-1-62576-045-6 (alk. paper)1. Backsiphonage (Plumbing)-Prevention. 2. Cross-connections (Plumbing) III. Title. IV. Title: Recommended practice for

14、 backflow prevention and cross-connection control. V. Series: AWWA manual ; M14. TH6523.A87 2015696.1-dc232014037357American Water Works Association6666 West Quincy AvenueDenver, CO 80235-3098awwa.orgPrinted in the United States of AmericaISBN: 978-1-62576-045-6 eISBN: 978-1-61300-309-1hours of work

15、 by your fellow water professionals.Revenue from the sales of this AWWA material supportsongoing product development. Unauthorized distribution,either electronic or photocopied, is illegal and hindersAWWAs mission to support the water community. This AWWA content is the product of thousands ofCopyri

16、ght 2015 American Water Works Association. All Rights Reserved.iiiContentsAWWA Manual 14List of Figures, vList of Tables, viiPreface, ixAcknowledgments, xiDedication, xiiiMetric Conversions, xvChapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17、. . . . . . . . . . . . . . . . . . .1Purpose of Manual, 1Responsibilities, 2Health Aspects, 5Legal Aspects, 7Chapter 2 Back ow Prevention Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11Basic Hydraulics, 11Types of Backflow, 13Assessing Degrees of H

18、azard, 18Assessing Other Risk Factors, 20Assessing the Effectiveness of Assemblies and Devices, 21Chapter 3 Program Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23Developing a Cross-Connection Control Program, 24Types of Programs, 25

19、Management Programs, 28Documentation, 33Human Resources, 33Program Administration, 35Chapter 4 Back ow Prevention Assembly Application, Installation, and Maintenance . . . .41Means of Preventing Backflow, 42Backflow Prevention Devices, 42Method for Controlling Backflow, 59Field Testing, 61Reference,

20、 64Chapter 5 Conducting a Cross-Connection Control Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Authority and Responsibilities, 66Purpose of a Cross-Connection Control Survey, 66Assessing the Degree of Hazard, 67Survey Considerations and Concepts, 67Conducting the Survey, 69Refere

21、nce, 74Chapter 6 Sample Hazards and Proper Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75Typical Hazards, 76Hazards Posed by a Water Supplier, 84Protection for Specific Customers, 89References, 91Copyright 2015 American Water Works Association. All Rights Reserv

22、ed.iv AWWA Manual M14BACKFLOW PREVENTION AND CROSS-CONNECTION CONTROLAppendix A Example Notices and Letters, 93Appendix B Testing Procedures or Methods, 99Appendix C Industry Resources, 181Appendix D Incidents Tables, 183Glossary, 187Index, 193List of AWWA Manuals, 203Copyright 2015 American Water W

23、orks Association. All Rights Reserved.vAWWA Manual M14Figures1-1 Examples of backflow prevention equipment locations, 42-1 Example of barometric loop in a piping configuration, 122-2 Backsiphonage backflow due to high rate of water withdrawal, 142-3 Backsiphonage backflow caused by reduced pressure

24、on suction side of booster pump, 152-4 Backsiphonage backflow caused by shutdown of water system, 152-5 Backpressure backflow caused by carbon dioxide cylinder, 172-6 Backpressure backflow caused by pumping system, 184-1 Common symbols used for backflow prevention devices, 434-2 Dual check device, 4

25、44-3 Dual check device with atmospheric port, 454-4 Atmospheric vacuum breaker, 454-5 Hose connection vacuum breaker, 464-6 Pressure vacuum breaker assembly, normal flow condition, 484-7 Pressure vacuum breaker assembly, backsiphonage condition, 484-8 Spill-resistant vacuum breaker, normal flow and

26、backsiphonage conditions, 504-9 Check valves open, permitting flow, 514-10 Backpressure, both check valves closed, 514-11 Negative supply pressure, check valves closed, 514-12 Typical double check valve assembly applications, 524-13 Reduced-pressure principle backflow prevention assembly, both check

27、 valves open and the differential relief valve closed, 544-14 Both check valves closed and the differential pressure relief valve open can be used for service protection or internal protection, 544-15 Backpressure: both check valves closed and the differential pressure relief valve closed, 544-16 Ba

28、cksiphonage: both check valves closed and the differential pressure relief valve open, 554-17 Typical reduced-pressure principle backflow prevention application, 554-18 Double check detector backflow prevention assembly, 574-19 Type II double check detector backflow prevention assembly, 574-20 Reduc

29、ed-pressure principle detector backflow prevention assembly, 584-21 Type II reduced-pressure principle detector backflow prevention assembly, 584-22 AG on tank, 594-23 AG on lavatory, 604-24 Typical AG applications, 604-25 Additional typical AG applications, 616-1 Cross-connection control, water tre

30、atment plants, 876-2 Service-containment and area-isolation water treatment plants, 88B-1 Double check valve assembly test, 101B-2 Double check valve assembly testback pressure condition, 102B-3 DCVAStep #1, 103Copyright 2015 American Water Works Association. All Rights Reserved.vi AWWA Manual M14BA

31、CKFLOW PREVENTION AND CROSS-CONNECTION CONTROLB-4 DCVAStep #2, 104B-5 DCVAStep #3 and DCVA Step #3A, 105B-6 Pressure vacuum breaker, 107B-7 PVBStep #1, 108B-8 PVBStep #2, 109B-9 PVBStep #3, 110B-10 RPZStep #1A, 112B-11 RPZStep #2, 113B-12 RPZStep #3, 114B-13 RPZStep #4, 115B-14 RPZStep #5, 116B-15 S

32、pill-resistant pressure vacuum breaker, 117B-16 Step 1, 118B-17 Step 2, 119B-18 Step 3, 120B-19 Sample test report form, 124B-20 Ground wire installation, 127B-21 Major component parts of five-valve differential pressure gauge test equipment, 139B-22 Differential pressure gauge test kit, five-valve

33、model, 140B-23 Differential pressure gauge showing hose connections to test the components of an RPBA, 140B-24 Differential pressure gauge showing hose connections to test the #1 check valve of a DCVA , 141B-25 Differential pressure gauge showing hose connections to test a PVBA air inlet, 141B-26 Di

34、fferential pressure gauge showing hose connections to test a PVBA check valve, 142B-27 Differential pressure gauge showing hose connections to test both the check valve and air inlet of an SVBA, 142B-28 Test 1CV#1, 171B-29 Test 3CV#2, 172B-30 Two-valve differential pressure test kit, 176B-31 Two-val

35、ve test kit, 176B-32 Three-valve test kit, 178B-33 Reduced-pressure field test with three-valve test kit, 179Copyright 2015 American Water Works Association. All Rights Reserved.viiAWWA Manual M14Tables2-1 Means of backflow prevention in the United States, 222-2 Selection guide for backflow prevente

36、rs in Canada, 226-1 Recommended protection for solar domestic hot-water systems, 846-2 Recommended protection at fixtures and equipment found in water treatment plants, 866-3 For service protection (containment), 896-4 Containment protection, 906-5 Typical backflow prevention devices, 906-6 Irrigati

37、on and hose connection protection, 91B-1 Safety-related publications, 129B-2 RPBA/RPDA test reporting, 133B-3 DCVA/DCDA test reporting, 134B-4 PVBA/SVBA test reporting, 137B-5 Approved minimum test result values, 137Copyright 2015 American Water Works Association. All Rights Reserved.This page inten

38、tionally blank.Copyright 2015 American Water Works Association. All Rights Reserved.ixPrefaceAWWA Manual M14This is the fourth edition of the AWWA Manual M14, Backflow Prevention and Cross-Connection Control: Recommended Practices. It provides both technical and general informa-tion to aid in the de

39、velopment, implementation, and management of a cross-connection control and backflow prevention program, and an understanding of backflow prevention and cross-connection control concepts. This manual is a review of recommended practice. It is not an AWWA standard calling for compliance with certain

40、requirements. It is intended for use by water suppliers and municipalities of all sizes, whether as a reference book or a textbook for those not familiar with backflow prevention and cross-connection control. This manual reviews regulatory provisions established to protect the potable water supply.

41、To achieve this goal, products and measures are discussed to assist in the deter-mination of controlling hazardous cross-connections. For fundamental knowledge and a thorough understanding, this entire manual should be carefully studied. Readers will also find the manual a useful source of informati

42、on when assistance is needed with spe-cific or unusual connections to the potable water supply. This fourth edition of M14 includes updates to regulatory concerns and products that protect the water supply, and new material on establishing programs to control cross- connections, including surveying

43、of piping systems to identify and monitor such connections.Copyright 2015 American Water Works Association. All Rights Reserved.This page intentionally blank.Copyright 2015 American Water Works Association. All Rights Reserved.xiAcknowledgmentsAWWA Manual M14The AWWA Technical and Educational Counci

44、l, the Distribution Plant Operations Division, and the Cross-Connection Control committee gratefully acknowledge the con-tributions made by those volunteers who drafted, edited, and provided the significant and critical commentary essential to updating M14. The Technical Review Board members dedicat

45、ed numerous hours in the final stages of preparation of this edition to ensure the overall technical quality, consistency, and accuracy of the manual.Technical Review Board MembersStuart F. Asay, Backflow Prevention Institute IAPMO, Westminster, Colo.Joseph A. Cotruvo, Joseph Cotruvo that those conn

46、ections will be operated and maintained to ensure water quality; and that public water suppliers have the basic knowledge needed to assist in this effort. The purpose of any such program is to reduce the risk of contamina-tion or pollution of the public water system. A cross-connection is an actual

47、or potential connection between any part of a potable water system and an environment that would allow substances to enter the potable water system. Those substances could include gases, liquids, or solids, such as chemicals, water products, steam, water from other sources (potable or nonpotable), a

48、nd any matter that may change the color or taste of water or add odor to water.* A.J. Keenan, C.S.I., B.C. Section AWWA Cross-Connection Control, September 1977.Copyright 2015 American Water Works Association. All Rights Reserved.2 BACKFLOW PREVENTION AND CROSS-CONNECTION CONTROL AWWA Manual M14RESP

49、ONSIBILITIESThe United States Safe Drinking Water Act (SDWA) became law in 1974. The purpose of the act is to protect public health by regulating all public drinking water supplies in the United States. SDWA was amended in 1986 and again in 1996. As amended, it requires pro-tection of the public drinking water supply and its sources: both surface water and ground water. SDWA does not, however, regulate private wells serving fewer than 25 individuals and it also does not regulate systems having fewer than 15 service connections.SDWA authorize