1、AWWA Standard SM Knife Gate Valves, Sizes 2 In. (50 mm) Through 96 In. (2,400 mm) Effective date: Sept. 1, 2014. First edition approved by AWWA Board of Directors June 20, 2010. This edition approved June 8, 2014. Approved by American National Standards Institute May 23, 2014. ANSI/AWWA C520-14 (Rev
2、ision of ANSI/AWWA C520-10) ii AWWA Standard This document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards describe minimum requirements and do not contain all of the engineering and administrative information normally contained in specifications. Th
3、e AWWA standards usually contain options that must be evaluated by the user of the standard. Until each optional feature is specified by the user, the product or service is not fully defined. AWWA pub- lication of a standard does not constitute endorsement of any product or product type, nor does AW
4、WA test, certify, or approve any product. The use of AWWA standards is entirely voluntary. This standard does not supersede or take precedence over or displace any applicable law, regulation, or codes of any governmental authority. AWWA standards are intended to represent a consensus of the water su
5、pply industry that the product described will provide satisfactory service. When AWWA revises or withdraws this standard, an official notice of action will be placed in the Official Notice section of Journal - American Water Works Association. The action becomes effective on the first day of the mon
6、th fol- lowing the month of Journal - American Water Works Association publication of the official notice. American National Standard An American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide
7、 to aid the manufacturer, the consumer, and the general public. The existence of an American National Standard does not in any respect preclude anyone, whether that person has ap - proved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not
8、conforming to the standard. American National Standards are subject to periodic review, and users are cautioned to obtain the latest editions. Producers of goods made in conformity with an American National Standard are encour - aged to state on their own responsibility in advertising and promotiona
9、l materials or on tags or labels that the goods are produced in conformity with particular American National Standards. Caution n oti Ce : The American National Standards Institute (ANSI) approval date on the front cover of this standard indicates completion of the ANSI approval process. This Americ
10、an National Standard may be revised or withdrawn at any time. ANSI procedures require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of ANSI approval. Purchasers of American National Standards may receive current information on all standard
11、s by calling or writing the American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036; (212) 642-4900, or emailing infoansi.org. ISBN-13, print: 978-1-62576-035-7 eISBN-13, electronic: 978-1-61300-295-7DOI: http:/dx.doi.org/10.12999/AWWA.C520.14 All rights reserved
12、. 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 in the form of brief excerpts or quotations for review purposes, without the written permission of the
13、publisher. Copyright 2014 by American Water Works Association Printed in USA hours of work by your fellow water professionals. Revenue from the sales of this AWWA material supports ongoing product development. Unauthorized distribution, either electronic or photocopied, is illegal and hinders AWWAs
14、mission to support the water community. This AWWA content is the product of thousands of iii Committee Personnel The AWWA Standards Committee, Knife Gate Valves, which prepared and approved this stan- dard, had the following personnel at the time of approval: Amzad Ali, Chair General Interest Member
15、s A. Ali, ADA Consulting Ltd., Surrey, B.C., Canada (AWWA) M.L. Altland, Hatch Mott Macdonald, Millburn, N.J. (AWWA) R.L. Gardner,* Wannacomet Water Company, Nantucket, Mass. (AWWA) T.J. McCandless,* Standards Engineer Liaison, AWWA, Denver, Colo. (AWWA) R. McLean, West Vancouver, B.C., Canada (AWWA
16、) Producer Members P.S. Gifford, Mueller Company, Chattanooga, Tenn. (AWWA) B. James, TTR Group Inc., Oakville, Ont., Canada (AWWA) A.W. Libke, DeZURIK, Sartell, Minn. (AWWA) User Members M.H. Johnson, Massachusetts Water Resources Authority, Reading, Mass. (AWWA) M. MacConnell, Metro Vancouver, Bur
17、naby, B.C., Canada (AWWA) N. Persaud, City of Toronto, Toronto, Ont., Canada (AWWA) J.V. Young, City of Richmond, Richmond, B.C., Canada (AWWA) * Liaison, nonvoting Alternate This page intentionally blank. v Contents All AWWA standards follow the general format indicated subsequently. Some variation
18、s from this format may be found in a particular standard. SEC. PAGE SEC. PAGE Foreword I Introduction vii I.A Background. vii I.B History vii I.C Acceptance vii II. Special Issues. .viii II.A General viii II.B Advisory Information on Product Application x II.C Advisory Information on Scheduling Requ
19、irements x III Use of This Standard xi III.A Purchaser Options and Alternatives xi III.B Data to Be Provided by the Manufacturer or Supplier xii III.C Modification to Standard .xiii IV Major Revisions xiii V Comments .xiv Standard 1 General 1.1 Scope 1 1.2 Purpose .1 1.3 Application 1 2 References 2
20、 3 Definitions .4 4 Requirements 4.1 Data Provided by Manufacturer or Supplier .5 4.2 Materials .5 4.3 General Design. 7 4.4 Manual Actuators. .12 4.5 Power Actuators 12 4.6 Workmanship and Coatings 12 5 Verification 5.1 Production Test Requirements .13 5.2 Proof-of-Design Test Requirements 14 6 Del
21、ivery 6.1 Requirements 15 Appendix A Installation A.1 General .17 A.2 Unloading .17 A.3 Storage 17 A.4 Installations .18 A.5 Operation 18 A.6 Maintenance .18 A.7 Record Keeping .18 vi Tables 1 Laying Length (Inches) 8 2 Stem Material 11 3 Stainless-Steel Valve Shaft And Stem Alloys 11 4 Cycle Leakag
22、e Test Requirements 15 vii Foreword This foreword is for information only and is not a part of ANSI*/AWWA C520. I. Introduction. I.A. Background. Knife gate valves are generally used for isolation of pipes in water and wastewater treatment plants. Knife gate valves can be metal or resilient seated,
23、bidirectional or unidirectional. I.B. History. Th e need for standardization of knife gate valves was recognized by the American Water Works Association (A WWA) in 2007 , resulting in the formation of a standards committee. The first edition of C520 was approved by the AWWA Board of Directors on Jun
24、e 20, 2010. This edition was approved on June 8, 2014. I.C. Acceptance. In May 1985, the US Environmental Protection Agency (USEPA) entered into a cooperative agreement with a consortium led by NSF International (NSF) to develop voluntary third-party consensus standards and a certification program f
25、or direct and indirect drinking water additives. Other members of the original consortium included the Water Research Foundation (formerly AwwaRF) and the Conference of State Health and Environmental Managers (COSHEM). The American Water Works Association and the Association of State Drinking Water
26、Administrators (ASDWA) joined later. In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states. Local agencies may choose to impose requirements more stringent than those required by the state. To evaluate the health effects of p
27、roducts and drinking water additives from such products, state and local agencies may use various references, including 1. An advisory program formerly administered by USEPA, Office of Drinking Water, discontinued on Apr. 7, 1990. 2. Specific policies of the state or local agency. 3. Two standards d
28、eveloped under the direction of NSF, NSF/ANSI 60, Drinking Water Treatment ChemicalsHealth Effects, and NSF/ANSI 61, Drinking Water System ComponentsHealth Effects. * American National Standards Institute, 25 West 43rd Street, Fourth Floor, New York, NY 10036. Persons outside the United States shoul
29、d contact the appropriate authority having jurisdiction. NSF International, 789 North Dixboro Road, Ann Arbor, MI 48105. viii 4. Other references, including AWWA standards, Food Chemicals Codex, Water Chemicals Codex,* and other standards considered appropriate by the state or local agency. Various
30、certification organizations may be involved in certifying products in accor- dance with NSF/ANSI 61. Individual states or local agencies have authority to accept or accredit certification organizations within their jurisdiction. Accreditation of certi- fication organizations may vary from jurisdicti
31、on to jurisdiction. Annex A, “Toxicology Review and Evaluation Procedures,” to NSF/ANSI 61 does not stipulate a maximum allowable level (MAL) of a contaminant for substances not regulated by a USEPA final maximum contaminant level (MCL). The MALs of an unspecified list of “unregulated contaminants”
32、are based on toxicity testing guidelines (noncarcinogens) and risk characterization methodology (carcinogens). Use of Annex A procedures may not always be identical, depending on the certifier. ANSI/AWWA C520 does not address additives requirements. Thus, users of this standard should consult the ap
33、propriate state or local agency having jurisdiction in order to 1. Determine additives requirements, including applicable standards. 2. Determine the status of certifications by parties offering to certify products for contact with, or treatment of, drinking water. 3. Determine current information o
34、n product certification. In an alternative approach to inadvertent drinking water additives, some jurisdictions (including California, Maryland, Vermont, and Louisiana at the time of this writing) are calling for reduced lead limits for materials in contact with potable water. Various third-party ce
35、rtifiers have been assessing products against these lead content criteria, and a new ANSI-approved national standard, NSF/ANSI 372, Drinking Water System ComponentsLead Content, was published in 2010. On Jan. 4, 2011, legislation was signed revising the definition for “lead free” within the Safe Dri
36、nking Water Act (SDWA) as it pertains to “pipe, pipe fittings, plumbing fittings, and fixtures.” The changes went into effect on Jan. 4, 2014. In brief, the new provisions to the SDWA require that these products meet a weighted average lead content of not more than 0.25 percent. II. Special Issues.
37、II.A. General. Conditions under which a valve is to be operated must be evaluated carefully by the purchaser. The evaluations must include the determination * Both publications available from National Academy of Sciences, 500 Fifth Street, NW, Washington, DC 20001. ix of the hydraulic characteristic
38、s of the system in which the valve will be installed and the operation of the valve, including (1) the maximum transient and static differential pressure across the valve gate and (2) flow through the valve under the most adverse operating conditions. Torque and thrust requirements for valve operati
39、on vary considerably with differential pressure across the valve, fluid velocity, and fluid temperature. Knife gate valves are not intended for throttling service. Shutoff direction is important in the installation and use of a knife gate valve. The valves performance and sealing characteristics var
40、y with direction of sealing. A manufacturer may designate a recommended high-pressure sealing side for long-term reliability. Installation: Knife gate valves may have protrusions in the bonnet area that may come in contact with oversize mating flanges. The top works of the valve may be sig - nifican
41、t and should be considered when designing the piping system. While knife gate valves are commonly provided with port flange bolt patterns (number of bolts, bolt size, bolt circle, etc.) that dimensionally match ANSI/AWWA C207, ANSI/AWWA C606, ASME *B16.1, ASME B16.5, ASME B16.42, MSS-SP-44, or ASME
42、B16.47 flange bolt patterns to facilitate installation, they are not designed to handle the same torque requirements of a Class 150 flange. With a lower nominal pressure rating, nar- row face-to-face dimension, and thinner body flanges, a knife gate body may distort if subjected to the full torque v
43、alues of a Class 150 flange, causing irreparable damage. Refer to manufacturers recommended flange torque values and recommended instal- lation instructions. Use of nontraditional flanging arrangements may exceed normal knife gate design criteria. Refer to manufacturers recommended installation inst
44、ructions. Gasket selection has a bearing on potential flange torques. Refer to manufacturers recommended installation instructions. Manual Actuation: Due to long linear travel during gate stroking, large knife gate valves require many rotations of handwheels or chainwheels with high rimpull force. T
45、his may be impractical and may fatigue operating personnel. It may be advisable to specify 2-in. nuts on input shaft of bevel gear actuators to allow use of powered torque devices. However, powered devices may over torque valves and/or actuators at the ends of the stroke if the devices are not prope
46、rly sized. When powered devices are employed, * ASME International, 3 Park Avenue, New York, NY 10016. x torque-limiting devices or declutching mechanisms set at 300 ft-lb (406 N-m) should be considered. Permeation: The selection of materials is critical for potable water, wastewater, and reclaimed
47、water service and distribution piping in locations where there is a likeli- hood the pipe will be exposed to significant concentrations of pollutants composed of low-molecular-weight petroleum products or organic solvents or their vapors. Research has documented that pipe materials, such as polyethy
48、lene, polybutylene, polyvinyl chloride, and asbestos cement; and elastomers, such as used in jointing gaskets and packing glands, are subject to permeation by lower-molecular-weight organic solvents or petroleum products. If a potable water, wastewater, or reclaimed water pipe must pass through such
49、 a contaminated area or an area subject to contamination, consult with the manufacturer regarding permeation of pipe walls, jointing material, and so forth, before selecting materials for use in that area. II.B. Advisory Information on Product Application. This standard does not describe all possible applications or manufacturing technologies. The purchaser should identify special requirements and required deviations from this standard and include appropriate language in purchase specifications. Refer to Sec. III.A in this foreword. Other advisory information is p
