Resilient-seated Gate Valves For Water Supply Service: Awwa Standard

American Water Works Association ANSI/AWWA C509-94 (Revision of ANSI/AWWA C509-87)

R

AWWA STANDARD FOR

RESILIENT-SEATED GATE VALVES FOR WATER SUPPLY SERVICE

All changes specified in addendum AWWA C509a-95 are incorporated into this standard. Effective date: Nov. 1, 1994. First edition approved by AWWA Board of Directors Jan. 28, 1980. This edition approved Jan. 30, 1994. Approved by American National Standards Institute Aug. 18, 1994.

AMERICAN WATER WORKS ASSOCIATION 6666 West Quincy Avenue, Denver, Colorado 80235

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

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. The 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 publication of a standard does not constitute endorsement of any product or product type, nor does AWWA test, certify, or approve any product. The use of AWWA standards is entirely voluntary. AWWA standards are intended to represent a consensus of the water supply industry that the product described will provide satisfactory service. When AWWA revises or withdraws this standard, an official notice of action will be placed on the first page of the classified advertising section of Journal AWWA. The action becomes effective on the first day of the month following the month of Journal AWWA 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 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 approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not 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 encouraged to state on their own responsibility in advertising and promotional materials or on tags or labels that the goods are produced in conformity with particular American National Standards. CAUTION NOTICE: The American National Standards Institute (ANSI) approval date on the front cover of this standard indicates completion of the ANSI approval process. This American 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 publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute, 11 W. 42nd St., New York, NY 10036; (212) 642-4900.

Copyright © 1994 by American Water Works Association Printed in USA

ii Copyright (C) 1998 American Water Works Association, All Rights Reserved.

Committee Personnel The AWWA Standards Committee on Gate Valves and Swing Check Valves, which reviewed and approved this standard, had the following personnel at the time of approval: Joseph J. Gemin, Chair Thomas M. Bowen, Vice-Chair Roland L. Larkin, Secretary Consumer Members R.E. Behnke, St. Louis County Water Company, St. Louis, Mo. T.M. Bowen, Manchester Water Works, Manchester, N.H. M.H. Burns, Denver Water, Denver, Colo. S.F. Gorden, Portland Water District, Portland, Maine Cassandra Hamvas, Los Angeles Department of Water & Power, Los Angeles, Calif. C.H. Kersey, Detroit Water & Sewer Department, Detroit, Mich. T.W. Knowlton,* Salem–Beverly Water Supply Board, Beverly, Mass.

(AWWA) (AWWA) (AWWA) (NEWWA) (AWWA) (AWWA) (NEWWA)

General Interest Members E.E. Baruth,† Standards Engineer Liaison, AWWA, Denver, Colo. K.M. Bell, Underwriters Laboratories Inc., Northbrook, Ill. T.J. Brown Jr., Factory Mutual Research Corporation, Norwood, Mass. K.J. Carl, Baldwin, N.Y. R.L. Claudy Jr., Orlando, Fla. J.B. Donohoe, Birmingham, Ala. C.R. Dugan,† Council Liaison, Board of Water & Light, Lansing, Mich. J.V. Fonley, Orange, Calif. J.J. Gemin, Proctor & Redfern Ltd., Kitchener, Ont. T.C. Jester, Consultant, Birmingham, Ala. S.J. Medlar, Camp, Dresser & McKee Inc., Edison, N.J. E.F. Straw, ISO Commercial Risk Services Inc., Duluth, Ga.

(AWWA) (UL) (FMRC) (AWWA) (AWWA) (AWWA) (AWWA) (AWWA) (AWWA) (AWWA) (NEWWA) (ISO)

Producer Members Jerry Bottenfield, Clow Valve Company, Oskaloosa, Iowa G.L. Bouc, Mueller Company, Decatur, Ill. L.R. Dunn, U.S. Pipe & Foundry Company, Birmingham, Ala. Les Engelmann, Ames Company Inc., Woodland, Calif. R.L. Larkin, American Flow Control, Birmingham, Ala. P.I. McGrath Jr.,* U.S. Pipe & Foundry Company, Birmingham, Ala. M.P. Yoke, M&H Valve Company, Anniston, Ala.

*Alternate †Liaison, nonvoting

iii Copyright (C) 1998 American Water Works Association, All Rights Reserved.

(MSS) (AWWA) (AWWA) (AWWA) (AWWA) (AWWA) (AWWA)

Contents SEC.

PAGE

SEC.

Foreword I II III IV V

History of Standard.......................... vi Information Regarding Use of This Standard ............................ vi Acceptance....................................... vii Modification to Standard .............. viii Major Revisions ............................. viii

Standard 1

General

1.1 1.2 1.3 1.4

Scope................................................... Definitions .......................................... References .......................................... Data to Be Supplied by Manufacturer................................... Affidavit of Compliance.....................

1.5

1 1 2 3 4

2

Materials

2.1 2.2

General ............................................... 4 Physical and Chemical Properties ........................................ 4

3

General Design

3.1 3.2

Structural Design .............................. 6 Size of Waterway ............................... 6

4

Detailed Design

4.1

Parts to Be Made of Gray or Ductile Iron................................. 6 Parts to Be Made of Brass or Bronze ......................................... 6 Body and Bonnet ............................... 6 Bolting ................................................ 7 Valve Ends ......................................... 7 Guides................................................. 8 Stem and Stem Nut........................... 8 Stem Sealing ...................................... 8 Packing ............................................... 9 Packing Glands, Gland Flanges, Gland Bolts, and Gland-Bolt Nuts ............................................... 10

4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

PAGE

4.11 4.12 4.13 4.14 4.15 4.16

Wrench Nuts and Handwheels....... Gearing............................................. Gear Cases ....................................... Indicators ......................................... Gaskets............................................. Valve Seats ......................................

10 11 11 11 11 12

5

Fabrication

5.1 5.2

Workmanship................................... 12 Coating ............................................. 12

6

Testing, Inspection, and Rejection

6.1 6.2 6.3

Proof of Design Testing................... 12 Production Testing .......................... 13 Plant Inspection and Rejection ...... 13

7

Marking and Shipping

7.1 7.2

Marking............................................ 14 Preparation for Shipment ............... 14

Appendix A

Installation, Operation, and Maintenance of ResilientSeated Gate Valves

A.1

General ........................................... 15

A.2

Unloading....................................... 15

A.3

Inspection Prior to Installation.................................. 15

A.4

Storage............................................ 16

A.5

Installation

A.5.1 A.5.2 A.5.3 A.5.4 A.5.5 A.5.6

Bolts.................................................. Underground Installation ............... Aboveground Installation................ Inspection ......................................... Testing.............................................. Records .............................................

iv Copyright (C) 1998 American Water Works Association, All Rights Reserved.

16 16 17 17 17 17

SEC.

PAGE

SEC.

A.5.7

Application Hazards ........................ 17

2

A.6

Inspection and Maintenance

A.6.1 A.6.2

Inspection ......................................... 18 Record Keeping ................................ 19

3 4

A.7

Repairs............................................ 19

5

Tables 1

6

PAGE

Minimum Thickness of Body and Bonnet ...................................... 7 Excess Flange Thickness .................. 8 Minimum Diameter of Stem and Minimum Number of Turns to Open ............................................ 9 Outside Diameter of Handwheels................................... 10 Gear Ratios ...................................... 11

Chemical and Physical Requirements for Bronze Used in Resilient-Seated Gate Valves .... 5

v Copyright (C) 1998 American Water Works Association, All Rights Reserved.

Foreword This foreword is for information only and is not a part of AWWA C509.

I. History of Standard. The resilient-seated gate valve has been commonly used in several European countries for many years. This type of valve has proven to be satisfactory in water utility applications. A resilient-seated gate valve similar to the European model was introduced into the US market and has been in service in various water utility applications since 1975. The American Water Works Association (AWWA) requested the assistance of the Manufacturers Standardization Society of the Valve and Fittings Industry (MSS) in providing a standard for resilient-seated gate valves at the 1976 AWWA annual conference. MSS played an important role in the development of this standard. The organization was created in 1924, and in 1930 it organized the MSS Water Works Committee and designated representatives for appointment to AWWA standards committees. Since that time, MSS has been particularly active and effective in developing new standards for the water utility industry and in making periodic revisions to existing standards. II. Information Regarding Use of This Standard. It is the responsibility of the user of an AWWA standard to determine that the products described in that standard are suitable for use in the particular application being considered. This standard includes certain options that, if desired, must be specified by the purchaser. Also, several items must be specified to describe completely the gate valve required. The following summarizes the items the purchaser should cover in the purchaser’s specifications and lists the sections in the standard where the items are discussed. 1. Standard used — that is, AWWA C509-94, Standard for Resilient-Seated Gate Valves for Water Supply Service. 2. Size and type of valve (Sec. 1.1). 3. Direction in which handwheel or wrench nut shall turn to open (Sec. 4.11.2). 4. Catalog data, net weight, and assembly drawings to be furnished by the manufacturer (Sec. 1.4) if required. 5. Affidavit of compliance (Sec. 1.5) if required. 6. Quantity required. 7. If records of tests specified in Sec. 6 are to be furnished. 8. If the valve will be subjected to water that promotes galvanic corrosion and requires the use of alternative materials as described in Sec. 2.2.4.4. 9. What alternative, if any, is desired in the type of rustproofing for bolts and nuts (Sec. 4.4). 10. Type of valve ends — flanged (Sec. 4.5.1), tapping valve flange (Sec. 4.5.4), mechanical joint (Sec. 4.5.2), or push-on joint (Sec. 4.5.3). 11. Type of stem seal — stuffing box or O-ring (Sec. 4.8). 12. Detailed description of wrench nut if not in accordance with Sec. 4.11. 13. Special cast markings (Sec. 7.1) if required.

vi Copyright (C) 1998 American Water Works Association, All Rights Reserved.

14. If bolting material with physical and chemical properties other than ASTM* A307 is required (Sec. 4.4). It is recommended that the purchaser verify with the supplier the appropriateness of any alternative bolting materials required. 15. Cutter diameter must be specified for tapping valves (Sec. 3.2). At the time this edition of AWWA C509 was approved, the US Environmental Protection Agency (USEPA) had enacted regulations to reduce quantities of asbestos fiber in the workplace and in the ambient air, thus lowering the exposure of the general public to the health risks associated with asbestos inhalation. Language in this standard no longer references the use of asbestos packing and gasket materials. Users of AWWA C509-94 should comply with USEPA, state, provincial, and local regulations regarding asbestos and consider the implications of using various alternative gasket and packing materials as listed in this standard. III. Acceptance. In May 1985, 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 for all direct and indirect drinking water additives. Other members of the consortium included the American Water Works Association Research Foundation (AWWARF), the Conference of State Health and Environmental Managers (COSHEM), the American Water Works Association (AWWA), and the Association of State Drinking Water Administrators (ASDWA). The consortium is responsible for the cooperative effort of manufacturers, regulators, product users, and other interested parties that develop and maintain the NSF standards. 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 products 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 developed under the direction of NSF, ANSI‡/NSF§ 60, Drinking Water Treatment Chemicals — Health Effects, and ANSI/NSF 61, Drinking Water System Components — Health Effects. 4. Other references, including AWWA standards, Food Chemicals Codex, Water Chemicals Codex,** and other standards considered appropriate by the state or local agency. Various certification organizations may be involved in certifying products in accordance with ANSI/NSF 61. Individual states or local agencies have authority to accept or accredit certification organizations within their jurisdiction. Accreditation of certification organizations may vary from jurisdiction to jurisdiction.

*American Society for Testing and Materials, 1916 Race St., Philadelphia, PA 19103. †Persons in Canada, Mexico, and non-North American countries should contact the appropriate authority having jurisdiction. ‡American National Standards Institute, 11 W. 42nd St., New York, NY 10036. §NSF International, 3475 Plymouth Rd., Ann Arbor, MI 48106. **Both publications available from National Academy of Sciences, 2102 Constitution Ave., N.W., Washington, DC 20418.

vii Copyright (C) 1998 American Water Works Association, All Rights Reserved.

Appendix A, “Toxicology Review and Evaluation Procedures,” to ANSI/NSF 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” are based on toxicity testing guidelines (noncarcinogens) and risk characterization methodology (carcinogens). Use of Appendix A procedures may not always be identical, depending on the certifier. AWWA C509-94 does not address additives requirements. Thus, users of this standard should consult the appropriate state or local agency having jurisdiction in order to 1. Determine additives requirements, including applicable standards. 2. Determine the status of certifications by all parties offering to certify products for contact with, or treatment of, drinking water. 3. Determine current information on product certification. IV. Modification to Standard. Any modification of the provisions, definitions, or terminology in the standard must be provided in the purchaser’s specifications. V. Major Revisions. The major revisions in this edition of AWWA C509 include the following: 1. Numerous modifications to conform to current AWWA form and content have been added. 2. The “Modification to Standard” and “Acceptance” sections have been added to the foreword. 3. Asbestos packing and gasket materials are no longer referenced in the standard. 4. Information on tapping valves has been added. 5. Soft metric equivalents have been added. 6. Definitions have been modified. 7. The Safe Drinking Water Act 1986 Amendments reference to maximum lead content in bronze has been added. 8. Repairs to castings of valve components have been clarified (Sec. 5.1.2.). 9. Discussion of 16-in. (400-mm) and 20-in. (500-mm) valves has been added to the scope of this standard (Sec. 1.1.1).

viii Copyright (C) 1998 American Water Works Association, All Rights Reserved.

American Water Works Association R

ANSI/AWWA C509-94 (Revision of ANSI/AWWA C509-87)

AWWA STANDARD FOR

RESILIENT-SEATED GATE VALVES FOR WATER SUPPLY SERVICE SECTION 1: GENERAL Sec. 1.1 Scope This standard covers iron-body, resilient-seated gate valves, including tapping gate valves, with nonrising stems (NRS) and outside-screw-and-yoke (OS&Y) rising stems for water supply service. 1.1.1 Sizes. Gate valves covered by this standard are 3 in. (75 mm), 4 in. (100 mm), 6 in. (150 mm), 8 in. (200 mm), 10 in. (250 mm), 12 in. (300 mm), 16 in. (400 mm), and 20 in. (500 mm) nominal pipe size (NPS). Sizes refer to the nominal diameter, in inches (or millimetres), of the waterway through the inlet and outlet connections and the closure area. 1.1.2 Valve pressure rating. The minimum design working water pressure shall be 200 psig (1,380 kPa [gauge]) for 3- through 12-in. (75- through 300-mm) size and 150 psig (1,034 kPa [gauge]) for 16- and 20-in. (400- and 500-mm) sizes. 1.1.3 Conditions and materials not covered. This standard is not intended to cover special conditions of installation or operation, such as built-in power drive, installation in vertical or steeply inclined lines, conveyance of unusually corrosive water, or excessive water hammer. Such conditions are beyond the intended scope of this standard and require special consideration in design and construction. Joint accessories for end connections, such as bolts, gaskets, glands, follower rings, and so forth, are not covered in this standard.

Sec. 1.2 Definitions In this standard, the following definitions shall apply: 1.2.1 Cosmetic defect: A blemish which has no effect on the ability of the component to meet the structural design and production test requirements of this standard. Should the blemish or the activity of plugging, welding, grinding, or

1

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2

AWWA C509-94

repairing of such blemish cause the component to fail these requirements, then the blemish shall be considered a structural defect. 1.2.2 Flanged joint. The flanged and bolted joint as described in AWWA/ANSI* C110/A21.10 or ANSI B16.1, class 125. 1.2.3 Manufacturer: The party that manufactures, fabricates, or produces materials or products. 1.2.4 Mechanical joint: The gasketed and bolted joint as described in ANSI/AWWA C111/A21.11. 1.2.5 NPS: Nominal pipe size. 1.2.6 Purchaser: The person, company, or organization that purchases any materials or work to be performed. 1.2.7 Push-on joint: The single rubber gasket joint as described in ANSI/AWWA C111/A21.11. 1.2.8 Structural defect: A flaw that causes the component to fail the structural design or test requirements of this standard. This includes, but is not limited to, imperfections that result in leakage through the walls of a casting, failure to meet the minimum wall-thickness requirement, or failure to meet production tests. 1.2.9 Tapping valve: A special gate valve designed with end connections and an unobstructed waterway to provide proper alignment and positioning of a tapping sleeve, valve, and machine for tapping pipe dry or under pressure.

Sec. 1.3 References This standard references the following documents. In their latest editions, they form a part of this standard to the extent specified herein. In any case of conflict, the requirements of this standard shall prevail. ANSI/Aerospace Standard† AS-568A — Aerospace Size Standard for O-rings. ANSI/ASME‡ B16.1 — Cast Iron Pipe Flanges and Flanged Fittings, Class 25, 125, 250 and 800. ANSI/ASME B16.10 — Face-To-Face and End-To-End Dimensions of Valves. ANSI/ASME B18.2.1 — Square and Hex Bolts and Screws Inch Series Including Hex Cap Screws and Lag Screws. ASTM§ A27 — Standard Specification for Steel Castings, Carbon, for General Application. ASTM A126 — Standard Specification for Gray Iron Castings for Valves, Flanges, and Pipe Fittings. ASTM A153 — Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware. ASTM A307 — Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength. ASTM A395 — Standard Specification for Ferritic Ductile Iron PressureRetaining Castings for Use at Elevated Temperatures. ASTM A536 — Standard Specification for Ductile Iron Castings.

*American National Standards Institute, 11 W. 42nd St., New York, NY 10036. †Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096. ‡American Society of Mechanical Engineers, 345 E. 47th St., New York, NY 10017. §American Society for Testing and Materials, 1916 Race St., Philadelphia, PA 19103.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

GATE VALVES

3

ASTM B154 — Standard Test Method for Mercurous Nitrate Test for Copper and Copper Alloys. ASTM B633 — Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel. ASTM B766 — Standard Specification for Electrodeposited Coatings of Cadmium. ASTM D395 — Standard Test Methods for Rubber Property — Compression Set. ASTM D429 — Standard Test Methods for Rubber Property — Adhesion to Rigid Substrates. ASTM D471 — Standard Test Method for Rubber Property — Effect of Liquids. ASTM D1149 — Standard Test Method for Rubber Deterioration — Surface Ozone Cracking in a Chamber. ASTM D2000 — Standard Classification System for Rubber Products in Automotive Applications. ANSI/AWWA C110/A21.10 — American National Standard for Ductile-Iron and Gray-Iron Fittings, 3 In. Through 48 In. (75 mm Through 1,200 mm), for Water and Other Liquids. ANSI/AWWA C111/A21.11 — American National Standard for Rubber-Gasket Joints for Ductile-Iron and Gray-Iron Pressure Pipe and Fittings. ANSI/AWWA C550 — Standard for Protective Epoxy Interior Coatings for Valves and Hydrants. Fed. Spec.* HH-P-106d — Packing; Flax or Hemp. Fed. Spec. TT-C-494b — Coating Compound, Bituminous, Solvent Type, Acid Resistant. MSS† SP-9 — Spot Facing for Bronze, Iron and Steel Flanges. MSS SP-60 — Connecting Flange Joint Between Tapping Sleeves and Tapping Valves.

Sec. 1.4 Data to Be Supplied by Manufacturer If requested by the purchaser, the manufacturer shall furnish the following information when filling orders for resilient-seated gate valves. 1.4.1 Catalog data. The manufacturer shall supply catalog data, including illustrations and a parts list, that identifies the materials to be used for making various parts. The information shall be in sufficient detail to serve as a guide in the assembly and disassembly of the valve and for ordering repair parts. 1.4.2 Weight information. The manufacturer shall furnish a statement of the net assembled weight for each size of valve exclusive of joint accessories. 1.4.3 Assembly drawings. The manufacturer shall submit to the purchaser one set of drawings showing the principal dimensions, construction details, and materials used for all parts of the valve. All work shall be done and all valves shall be furnished in accordance with these drawings after the drawings have been reviewed and accepted by the purchaser.

*Federal Specifications available from Naval Publications and Forms Center, 5801 Tabor Ave., Philadelphia, PA 19120. †Manufacturers Standardization Society of the Valve and Fittings Industry, 127 Park St. NE, Vienna, VA 22180.

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4

AWWA C509-94

Sec. 1.5 Affidavit of Compliance The manufacturer shall, when required by the purchaser’s specifications, furnish the purchaser with an affidavit stating that the valve and all materials used in its construction conform to the applicable requirements of this standard and the purchaser’s specifications, and that all tests specified therein have been performed and all test requirements have been met.

SECTION 2: MATERIALS Sec. 2.1 General When reference is made to ANSI, ASTM, AWWA, or other standards, it shall be understood that the latest revision thereof shall apply. All materials used in valves produced under this standard shall conform to the requirements stipulated in the following sections.

Sec. 2.2 Physical and Chemical Properties The requirements of ANSI, ASTM, AWWA, or other standards referenced in this text shall govern the physical and chemical characteristics of the valve components. Whenever valve components are to be made in conformance with AWWA, ANSI, ASTM, or other standards that include test requirements or testing procedures, such requirements or procedures shall be complied with by the manufacturer. The records of all tests shall, if required by the purchaser’s specifications, be made available to the purchaser. 2.2.1 Gray iron. Gray iron shall conform to or exceed the requirements of ASTM A126 class B. 2.2.2 Ductile iron. Ductile iron shall conform to the requirements of ASTM A395 or ASTM A536. 2.2.3 Steel. Carbon–steel castings, when used, shall be ASTM A27 grade U-60-30 or equal. 2.2.4 Brass or bronze. Brass or bronze used in valves shall comply with the following: 2.2.4.1 Valve components of brass or bronze shall be made to ASTM or Copper Development Association* (CDA) recognized alloy specifications. 2.2.4.2 The chemical and physical requirements shown in Table 1 shall apply. 2.2.4.3 Any bronze alloy used in the cold-worked condition shall be capable of passing the mercurous nitrate test in accordance with ASTM B154 to minimize susceptibility to stress corrosion. 2.2.4.4 Waters in some areas promote galvanic corrosion in the form of dezincification or dealuminization. Grades B and C bronze shall not be used in such waters. If aluminum bronze is used, the alloys shall be inhibited against dealuminization by proper application of a temper anneal or other suitable means. 2.2.4.5 Bronze components that contact drinking water shall not contain more than 8 percent lead (US Safe Drinking Water Act Amendments of 1986).

*Copper Development Association, Greenwich Office Park 2, P.O. Box 1840, Greenwich, CT 06836-1840.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

GATE VALVES

5

Table 1 Chemical and physical requirements for bronze used in resilient-seated gate valves Minimum Yield Strength psi (kPa)

Grade of Bronze A B C D E

14,000 20,000 32,000 20,000 32,000

(96,500) (137,800) (220,500) (137,800) (220,500)

Minimum Elongation in 2 in. (50.8 mm)* %

Copper Minimum %

Zinc Maximum %

15 15 10 15 10

79 57 57 79 79

16 — — 16 16

*Throat length of sample.

2.2.5 Gaskets. Gasket material shall be made of inorganic mineral fiber, rubber composition, or paper that is free from corrosive ingredients. O-rings or other suitable elastomeric seals may be used for gaskets. 2.2.6 O-rings. O-rings shall meet the requirements of ASTM D2000 and have physical properties suitable for the application. 2.2.7 Coatings. Unless otherwise specified by the purchaser, valve coatings, as specified in Sec. 5.2., shall at a minimum conform to Fed. Spec. TT-C-494b or ANSI/AWWA C550. 2.2.8 Elastomers. Elastomers shall comply with the following: 2.2.8.1 Rubber seats shall be resistant to microbiological attack, copper poisoning, and ozone attack. 2.2.8.2 Rubber-seat compounds shall contain no more than 8 parts per million (ppm) of copper ion and shall include copper inhibitors to prevent copper degradation of the rubber material. 2.2.8.3 Rubber-seat compounds shall be capable of withstanding an ozone resistance test when tested in accordance with ASTM D1149. The tests shall be conducted on unstressed samples for 70 h at 104°F (40°C) with an ozone concentration of 50 parts per hundred million (pphm) without visible cracking in the surfaces of the test samples after the tests. 2.2.8.4 Rubber-seat compounds shall have a maximum compression set value of 20 percent when tested in accordance with ASTM D395, method B, for 22 h at 158°F (70°C). 2.2.8.5 Rubber-seat compounds shall contain no more than 1.5 parts of wax per 100 parts of rubber hydrocarbon and shall have less than 2 percent volume increase when tested in accordance with ASTM D471 after being immersed in distilled water at 73.4°F ± 2°F (23°C ± 1°C) for 70 h. Reclaimed rubber shall not be used. 2.2.8.6 Rubber-seat compounds shall be free of vegetable oils, vegetable-oil derivatives, animal fats, and animal oils.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

6

AWWA C509-94

SECTION 3: GENERAL DESIGN Sec. 3.1 Structural Design All parts of all valves shall be designed to withstand, without being structurally damaged, (1) an internal test pressure of twice the rated design working pressure of the valve and (2) the full rated internal working pressure when the closure member is cycled once from a fully open to a fully closed position against the full rated unbalanced working water pressure. In addition to these pressure requirements, the valve assembly and mechanism shall be capable of withstanding an input torque as follows: 3 in. and 4 in. (75 mm and 100 mm) NPS — 200 ft-lb (270 N m); 6 in. (150 mm), 8 in. (200 mm), 10 in. (250 mm), and 12 in. (300 mm) NPS — 300 ft-lb (406 N m). For sizes larger than 12 in. (300 mm), consult the manufacturer.

⋅

⋅

Sec. 3.2 Size of Waterway With the valve open, an unobstructed waterway shall be provided. The waterway shall have a diameter equal to or larger than the full nominal diameter of the valve. For tapping valves, the size of the waterway shall include the appropriate clearance for the diameter of the tapping machine cutter recommended by the valve manufacturer. Some valves may require an undersized cutter, which is smaller than the nominal diameter of the valve.

SECTION 4: DETAILED DESIGN Sec. 4.1 Parts to Be Made of Gray or Ductile Iron The following parts of the valve shall be made of either gray or ductile iron: bonnet, body, yoke, handwheel, wrench nut, O-ring packing plate or seal plate, and gland follower. The gate may be made of gray or ductile iron.

Sec. 4.2 Parts to Be Made of Brass or Bronze The stem nuts, glands, and bushings for NRS valves, and the followers or glands and bonnet bushings on OS&Y valves, shall be made of grade A, B, C, D, or E bronze. The stem shall be made of cast, forged, or rolled grade B, C, D, or E bronze. The gate may be made of bronze grade A, B, C, D, or E.

Sec. 4.3 Body and Bonnet 4.3.1 Shell thickness. Shell thickness measurements taken at points diametrically opposite to each other shall, when added together and divided by two, equal or exceed the minimum metal thicknesses given in Table 2. Shell thickness at no point shall be more than 12.5 percent thinner than the minimum metal thickness called for in Table 2, and no continuous area of deficient thickness shall exceed 12.5 percent of the pressure-containing shell area of the casting. 4.3.2 Yokes on OS&Y valves. On OS&Y valves, the yoke on bonnets may be integral or of bolted-on construction. The design shall be such that a hand cannot be jammed between a yoke and the handwheel. 4.3.3 Stem opening on OS&Y valves. With OS&Y valves, the opening through the bonnet for the stem shall be bushed with grade A, B, C, D, or E bronze, finished

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GATE VALVES

7

Table 2 Minimum thickness of body and bonnet Valve Diameter NPS, in. (mm) 3 4 6 8 10 12 16 20

(75) (100) (150) (200) (250) (300) (400) (500)

Minimum Thickness* in. (in. fractions) 0.37 0.40 0.43 0.50 0.63 0.68 0.85 0.97

(3⁄8) (13⁄32) (7⁄16) (1⁄2) (5⁄8) (11⁄16) (27⁄32) (31⁄32)

(mm) (9) (10) (11) (13) (16) (17) (22) (25)

*The decimal value should be used when the two expressions are not exactly equivalent.

on the underside or otherwise designed to make a joint with the stem or stem nut when the gate is wide open.

Sec. 4.4 Bolting Bolting materials shall develop the physical strength requirements of ASTM A307 and may have either regular square or hexagonal heads with dimensions conforming to ANSI B18.2.1. Bolts, studs, and nuts shall be (1) cadmium-plated (ASTM B766) or zinc-coated (ASTM A153 or ASTM B633), or (2) rustproofed by some other process disclosed to and acceptable to the purchaser. The purchaser may require that bolts, studs, and nuts shall be made from a specified corrosion-resistant material, such as low-zinc bronze, nickel–copper alloy, or stainless steel.

Sec. 4.5 Valve Ends End connections shall conform to one of the following requirements: 4.5.1 Flanged ends. The end flanges of flanged valves shall conform to dimensions and drillings of ANSI B16.1 class 125, or ANSI/AWWA C110/A21.10 unless explicitly provided otherwise in the purchaser’s specifications. Unless spot-facing is required by the purchaser’s specifications, the bolt holes of the end flanges shall not be spot-faced except when the thickness at any point within the spot-face area, as defined in MSS SP-9, exceeds the required minimum thickness by more than that indicated in Table 3 or if the flange is not sufficiently flat. If the foregoing limit is exceeded, either spot-facing or back-facing may be used to meet the requirements. When required, all spot-facing shall be done in accordance with MSS SP-9. Bolt holes shall straddle the vertical centerline of the valve, unless otherwise specified by the purchaser. The laying lengths of flanged valves 12 in. (300 mm) and smaller shall conform to the requirements for double-disc gate valves listed in Table 1 of ANSI/ASME B16.10. 4.5.2 Mechanical-joint ends. Mechanical-joint bell dimensions shall conform to ANSI/AWWA C111/A21.11. Slots with the same width as the diameter of the bolt holes may be provided instead of holes in the bell flange at those places where the valve body and bonnet interfere with the joint assembly. 4.5.3 Push-on joint ends. Push-on joints shall conform to the requirements of ANSI/AWWA C111/A21.11.

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Table 3 Excess flange thickness Nominal Valve Size NPS, in. (mm) 3–12 16–20

(75–300) (400–600)

Excess Thickness (minimum) in. (mm) 1⁄8 3⁄16

(3.2) (4.8)

4.5.4 Tapping-valve ends. 4.5.4.1 The end flange of a tapping valve that forms a joint with the tapping sleeve shall conform to the dimensions of MSS SP-60 in sizes 3 in. (75 mm) through 12 in. (300 mm) NPS. For larger sizes, flange dimensions shall be as agreed to by the purchaser and supplier. 4.5.4.2 The connecting flange of the tapping valve mating with the tapping machine must be parallel and concentric with the opposite flange and concentric with the waterway to provide proper alignment for the tapping operation.

Sec. 4.6 Guides If guiding is necessary to obtain shut off, the design shall be such that corrosion in the guide area does not affect sealing.

Sec. 4.7 Stem and Stem Nut 4.7.1 Stem collars. All stem collars shall be made integral with stems on NRS valves. The stem on OS&Y valves shall be so constructed as to make a backseat with the pressure side of the bonnet or bushing when the gate is wide open. The backseat should allow repacking according to Sec. 4.8.1. 4.7.2 Threads. The threads of stems and stem nuts (disc bushings) shall be of Acme, modified Acme, or one-half V-type. 4.7.3 Thread forming. Stems and stem nuts shall be threaded straight and true and shall work true and smooth and in perfect line throughout the lift of opening and thrust of closing the valve. 4.7.4 Diameter. The stem diameters and turns to open shall be as shown in Table 4. 4.7.5 OS&Y stems. OS&Y valve stems shall be of sufficient length so as to be at least flush with the top of the yoke nut after the gate is fully closed. The design shall prevent any possibility of the gate leaving the stem or turning during the operation of the valve. 4.7.6 Materials. Valve stems shall be cast, forged, or rolled bronze. Bronze shall be grade B, C, D, or E. Stem nuts shall be grade A, B, C, D, or E bronze. 4.7.7 Stress corrosion. Valve stems and valve parts manufactured from some grades of manganese bronze or some other materials are subject to stress corrosion. The manufacturer shall design the valve and select materials to minimize stress corrosion.

Sec. 4.8 Stem Sealing 4.8.1 Stuffing boxes. The stuffing box shall be designed so that the valve can be packed under pressure when in the fully open position.

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Table 4 Minimum diameter of stem and minimum number of turns to open OS&Y Valves NRS Valves

Valve Size NPS, in. (mm) 3 4 6 8 10 12 16 20

(75) (100) (150) (200) (250) (300) (400) (500)

Minimum Minimum Diameter of Stem Number of (at base of thread)* Turns of Stem in. (mm) to Open 0.859 0.859 1.000 1.000 1.125 1.188 1.438 1.750

(21.82) (21.82) (25.40) (25.40) (28.58) (30.18) (36.53) (44.45)

9 12 18 24 30 36 48 40

Minimum Diameter of Stem Unthreaded Section and Thread OD† in. (mm) 3⁄4

1 1 1 1 1 1 —

1⁄8 1⁄4 3⁄8 3⁄8 1⁄2

(19.1) (25.4) (28.6) (31.8) (34.9) (34.9) (38.1) —

Minimum Number of Turns of Stem to Open‡ 7 9 18 25 31 37 48 —

*The diameter of the stem at the base of the thread or at any point below that portion shaped to receive the wrench nut on NRS valves, or the minimum diameter of the stem unthreaded section and thread OD for OS&Y valves, shall not be less than specified. †Outside diameter. ‡Valves shown for 6–12 in. (150–300 mm) NPS sizes are for single-lead threads. If a double-lead thread is used, minimum turns become 13, 17, 21, and 25 for sizes 6–12 in. (150–300 mm) NPS inclusive.

4.8.1.1 On NRS valves, the stem opening, thrust-bearing recess, and bonnet face of the stuffing box shall be machined or finished in a manner that provides a smooth surface that is either parallel or perpendicular to the stem axis within 0.5°. 4.8.1.2 Stuffing boxes shall have a depth not less than the diameter of the valve stem. The internal diameter shall be large enough to contain adequate packing to prevent leakage around the stem. 4.8.2 O-rings. When an O-ring or other pressure-actuated stem seal is used, the design shall incorporate two such seals. The dimensions of such seals shall be in accordance with AS-568A. The sealing system shall be designed to remain watertight at pressures required by this standard. The seals shall be designed for dynamic applications. 4.8.2.1 The valve shall be so designed that the seal above the stem collar can be replaced with the valve under pressure in the fully open position. 4.8.3 Materials. A stuffing box or O-ring packing plate shall be made of cast iron. Thrust surfaces and stem openings, if bushed, or stem-seal cartridges shall be made of grade A, B, C, D, or E bronze or a synthetic polymer with physical properties suitable for the application. Stem-seal bolts and nuts shall conform to the requirements specified in Sec. 4.4.

Sec. 4.9 Packing 4.9.1 Material. Stuffing-box packing shall be made of flax conforming to Fed. Spec. HH-P-106d or other appropriate material. Hemp, asbestos, or jute packing shall not be used.

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4.9.2 Installation. Stuffing boxes shall be packed properly and ready for service when valves are delivered to the purchaser. Adjustment of stuffing-box bolts may be required to seal leakage at the time of installation.

Sec. 4.10 Packing Glands, Gland Flanges, Gland Bolts, and Gland-Bolt Nuts The packing-gland assembly shall be of solid, solid-bushed, or two-piece design. Gland flanges (followers) may be formed as a flanged end on the gland or as a separate part. 4.10.1 Material. Packing glands for valves sizes 12 in. (300 mm) NPS and smaller shall be made of grade A, B, C, D, or E bronze. Packing glands for valves larger than 12 in. (300 mm) NPS may be made of cast iron and bushings of grade A, B, C, D, or E bronze. 4.10.2 Packing-gland flange. If a packing-gland flange (follower) is used, it shall be made of either cast iron or grade A, B, C, D, or E bronze. 4.10.3 Packing-gland bolts. Packing-gland bolts shall be made either of grade B, C, D, or E bronze or rustproofed steel according to Sec. 4.4. Gland-bolt nuts shall be made of grade B, C, D, or E bronze.

Sec. 4.11 Wrench Nuts and Handwheels Wrench nuts and handwheels shall be made of gray iron or ductile iron. Unless otherwise explicitly required by the purchaser’s specifications, the wrench nuts shall be 115⁄16 in. (49.2 mm) square at the top, 2 in. (50.8 mm) square at the base, and 13⁄4 in. (44.5 mm) high. The outside diameter of handwheels shall not be less than those given in Table 5. Nuts shall have a flanged base on which shall be cast an arrow at least 2 in. (50.8 mm) long showing the direction of opening. The word “OPEN,” in 1⁄2-in. (12.7-mm) or larger letters, shall be cast on the nut to indicate clearly the direction to turn the wrench when opening the valve. Handwheels shall be of the spoke type only. Webbed or disc types are not permissible. An arrow showing the direction to turn the handwheel to open the valve, with the word “OPEN” in 1⁄2-in. (12.7-mm) or larger letters in a break in the arrow shaft, shall be cast on the rim of the handwheel so as to be readily readable. 4.11.1 Operating mechanism. NRS valves are to be supplied with wrench nuts for buried service and handwheels for aboveground service. OS&Y valves are to be supplied with handwheels.

Table 5 Outside diameter of handwheels*

Size of Valve NPS, in. (mm) 3 4 6 8 10 12

(75) (100) (150) (200) (250) (300)

Minimum Diameter of Handwheel in. (mm) 7 10 12 14 16 16

(178) (254) (305) (356) (406) (406)

*For sizes larger than 12 in. (300 mm), consult the manufacturer.

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4.11.2 Direction of opening. For OS&Y valves, the standard direction of opening is counterclockwise as viewed from the top. Valves opening in the opposite direction (clockwise) may be supplied if specifically ordered. Both directions of opening are considered standard for NRS valves. 4.11.3 Method of securing. Wrench nuts shall be fitted to the top of the valve stem and secured in position by mechanical means. 4.11.4 Access to packing-gland bolts. The flanged base of the wrench nut may be shaped or cut away to permit access from the ground surface to the packinggland bolts with an extension socket wrench. 4.11.5 Color coding. Wrench nuts and handwheels that open the valve by turning to the right (clockwise) shall be painted red. Wrench nuts and handwheels that open the valve by turning to the left (counterclockwise) shall be painted black.

Sec. 4.12 Gearing If required by the purchaser’s specifications, gears shall be accurately formed and smooth running, with a pinion shaft of bronze or equivalent material operating in a bronze, self-lubricating or permanently sealed antifriction bearing. 4.12.1 Material. Geared valves shall be equipped with steel gears unless castiron gears are explicitly required by the purchaser’s specifications. Pinions shall be steel. Material for steel gears shall be ASTM A27 grade U-60-30 or equal. 4.12.2 Gear Ratio. Gear ratios shall not be less than those shown in Table 6.

Sec. 4.13 Gear Cases Valves using O-ring or V-type stem seals may have the gear case attached directly to the valve. When geared valves are furnished, enclosed gear cases are required unless definitely excluded by the purchaser’s requirements. Two types of gear cases may be furnished — the extended type or the totally enclosed type. The extended type shall be attached to the bonnet of the valve in such a manner as to permit repacking of the stuffing box of the valve without detaching the gear case. The totally enclosed type shall enclose both stuffing box and gearing.

Sec. 4.14 Indicators When required by the purchaser’s specifications, geared valves shall be equipped with indicators to show the position of the gate in relation to the waterway.

Sec. 4.15 Gaskets Gaskets, O-rings, or other suitable elastomeric seals shall be used on all flanged joints intended to be watertight.

Table 6 Gear ratios Valve Diameter NPS, in. (mm) 16 20

(400) (500)

Minimum Gear Ratio 2:1 2:1

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AWWA C509-94

Sec. 4.16 Valve Seats Resilient seats shall be applied to the gate and shall seat against a corrosionresistant surface. The surface may be either metallic or nonmetallic, applied in a manner to withstand the action of line fluids and the operation of the sealing gate under long-term service. A metallic surface shall have a corrosion resistance equivalent to or better than bronze. A nonmetallic surface shall be in compliance with ANSI/AWWA C550. Resilient seats shall be bonded or mechanically attached to the gate. The method used for bonding or vulcanizing shall be proved by ASTM D429; either method A or method B. For method A, the minimum strength shall not be less than 250 psi (1,725 kPa). For method B, the peel strength shall not be less than 75 lb/in. (9.3 kg/m). All exposed mechanical attaching devices and hardware used to retain the resilient seat shall be made of a corrosion-resistant material.

SECTION 5: FABRICATION Sec. 5.1 Workmanship 5.1.1 Interchangeable parts. All parts shall conform to their required dimensions and shall be free from defects that could prevent proper functioning of the valve. When assembled, valves manufactured in accordance with this standard shall be well-fitted and shall operate smoothly. All like parts of valves of the same model and size produced by the same manufacturer shall be interchangeable. 5.1.2 Castings. All castings shall be clean and sound, without defects that will weaken their structure or impair their service. Plugging, welding, or repairing of cosmetic defects is allowed. Repairing of structural defects is not allowed unless agreed to by the purchaser. Repaired valves shall comply with the testing requirements of this standard after repairs have been made. Repairs within the bolt circle of any flange face are not allowed.

Sec. 5.2 Coating 5.2.1 Interior ferrous surfaces. A coating conforming to ANSI/AWWA C550 shall be applied to the interior ferrous surfaces of the valve body that will be in contact with liquid. Other exposed interior ferrous surfaces, except finished or bearing surfaces, shall be coated with a material specified in Sec. 2.2.7. 5.2.2 Exterior ferrous surfaces. A coating material as specified in Sec. 2.2.7 shall be applied to all exterior ferrous surfaces except fasteners.

SECTION 6: TESTING, INSPECTION, AND REJECTION Sec. 6.1 Proof of Design Testing 6.1.1 Hydrostatic test. One prototype valve of each size and class of a manufacturer’s design shall be hydrostatically tested with twice the specified rated pressure applied to one side of the gate and zero pressure applied to the other side. The test is to be made in each direction across the gate. During this hydrostatic test,

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the manufacturer may make special provisions to prevent leakage past the seats. No part of the valve or gate shall be permanently deformed by the test. 6.1.2 Torque test. A prototype of each size of valve shall be overtorqued in the closed and open positions to demonstrate that there is no distortion of the valve stem or damage to the resilient seat as evidenced by failure to seal at rated pressure. The applied torque shall be 250 ft-lb (340 N m) for 3-in. (75-mm) and 4-in. (100-mm) NPS valves; 350 ft-lb (475 N m) for 6-in. (150-mm), 8-in. (200-mm), 10-in. (250-mm), and 12-in. (300-mm) NPS valves; and 400 ft-lb (545 N m) for 16-in. (400mm) and 20-in. (500-mm) NPS valves. Torque shall be directly applied to the valve stem. 6.1.3 Leakage test. Two prototype valves of each size chosen by the manufacturer to represent the extremes of seat compression shall be fully opened and closed to a seal for 500 complete cycles with sufficient flow that the valve is at the rated working pressure for the pressure differential at the point of closing. The valves shall be drip-tight under rated pressure differential applied alternately to each side of the gate after completion of the tests. 6.1.4 Pressure test. One prototype of each valve size shall be tested to 2.5 times the rated working pressure with the gate in the open position. There shall be no rupture or cracking of the valve body, valve bonnet, or seal plate. Leakage at pressure-containing joints shall not be a cause for failure of the test.

⋅

⋅

⋅

Sec. 6.2 Production Testing After manufacture, each gate valve shall be subjected to operation and hydrostatic tests at the manufacturer’s plant as specified in this section. 6.2.1 Operation test. Each valve shall be operated through a complete cycle in the position for which it was designed to ensure free and proper functioning of all parts in the intended manner. Any defects in workmanship shall be corrected and the test repeated until satisfactory performance is demonstrated. 6.2.2 Shell test. A hydrostatic test pressure equal to twice the rated working pressure of the valve shall be applied to the assembled valve with the gate in the open position. The test shall show no leakage through the metal, pressure-containing joints, or stem seals. 6.2.3 Seat test. A test shall be made from each direction at rated working pressure to prove the sealing ability of each valve from both directions of flow. The test shall show no leakage through the metal, pressure-containing joints, or past the seat.

Sec. 6.3 Plant Inspection and Rejection All work performed in accordance with this standard, except prototype testing, shall be subject to inspection and acceptance by the purchaser. The purchaser shall at all times have access to all places of manufacture where materials are being produced or fabricated, or where tests are conducted. The purchaser shall be accorded full facilities for inspection and observation of tests during plant inspection. Any valve or part not conforming to the requirements of this standard shall be made satisfactory or shall be rejected and repaired or replaced by the manufacturer. Repaired valves must be acceptable to the purchaser and specifically accepted when submitted or resubmitted. Whether the purchaser has a representative at the plant or not, an affidavit of compliance may be required from the manufacturer as provided in Sec. 1.5 of this standard.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

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SECTION 7: MARKING AND SHIPPING Sec. 7.1 Marking Markings shall be cast on the bonnet or body of each valve and shall show the manufacturer’s name or mark, the year the valve casting was made, the size of the valve, and the designation of working water pressure, for example, “200W.” Special markings in addition to these can be supplied when specified by the purchaser’s requirements on agreement between purchaser and manufacturer.

Sec. 7.2 Preparation for Shipment Valves shall be complete in all details when shipped. The manufacturer shall use reasonable care in preparing valves for shipment. Valves shall be drained before shipment.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

APPENDIX A Installation, Operation, and Maintenance of Resilient-Seated Gate Valves This appendix is for information only and is not a part of AWWA C509.

SECTION A.1: GENERAL Resilient-seated gate valves form a significant component of many fire-fighting or water-distribution systems. Failure of a resilient-seated gate valve in such systems, either due to faulty installation or improper maintenance, could result in extensive damage and costly repairs. In addition, many resilient-seated gate valves are installed in buried-service or underground applications. Problems with or malfunctions of the valves due to faulty installation or improper maintenance can result in extensive and costly unearthing operations to effectively correct or eliminate the problem. Many resilient-seated gate-valve problems and failures can be traced back to improper installation, operation, or maintenance procedures.

SECTION A.2: UNLOADING All valves should be unloaded carefully. Each valve should be carefully lowered from the truck to the ground; it should not be dropped. In the case of larger valves, forklifts or slings around the body of the valve or under the skids should be used for unloading. Only hoists and slings with adequate load capacity to handle the weight of the valve or valves should be used. Hoists should not be hooked into or chains fastened around yokes, gearing, motors, cylinders, or handwheels. Failure to carefully follow these recommendations is likely to result in damage to the valve.

SECTION A.3: INSPECTION PRIOR TO INSTALLATION Resilient-seated gate valves should be inspected at the time of receipt for damage in shipment. The initial inspection should verify compliance with specifications, direction of opening, size and shape of operating nut, number of turns to open or close, and type of end connections. A visual inspection of the seating surfaces should be performed to detect any damage in shipment or scoring of the seating surfaces. Inspection personnel should look for bent stems, broken handwheels, cracked parts, loose bolts, missing parts and accessories, and any other evidence of mishandling during shipment. Each valve should be operated through one complete opening-andclosing cycle in the position in which it is to be installed.

15

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

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AWWA C509-94

SECTION A.4: STORAGE Valves should be stored in the fully closed position to prevent the entry of foreign material that could cause damage to the seating surfaces. Whenever practical, valves should be stored indoors. If outside storage is required, means should be provided to protect the operating mechanism, including gears, motor actuators, and cylinders, from weather elements. During outside storage, valves should be protected from the weather, sunlight, ozone, and foreign materials. In colder climates where valves may be subject to freezing temperatures, it is absolutely essential to remove water from the valve interior and close the valve before storage. Failure to do so may result in a cracked valve casting and/or deterioration of the resilient seat material.

SECTION A.5: INSTALLATION Instructions supplied by manufacturers should be reviewed in detail before valves are installed. At the jobsite prior to installation, each valve should be visually inspected and any foreign material in the interior portion of the valve should be removed. A detailed inspection of the valve as outlined in Sec. A.3 should be performed prior to installation.

Sec. A.5.1 Bolts All bolts should be checked for proper tightness and protected by the installer to prevent corrosion, either with a suitable paint or by polyethylene wrapping.

Sec. A.5.2 Underground Installation Valves in water-distribution lines shall, where practical, be located in easily accessible areas. A.5.2.1 During installation there is the possibility of foreign materials inadvertently entering the valve. Foreign material can damage internal working parts during operation of the gate valve. For this reason, gate valves should be installed in the closed position. Each valve should be placed on firm footing in the trench to prevent settling and excessive strain on the connection to the pipe. Piping systems should be supported and aligned to avoid damage to the valve. A.5.2.2 A valve box or vault should be provided for each valve used in a buried-service application. The valve box should be installed so as not to transmit shock loads or stress to the valve. The valve box should be centered over the operating nut of the valve with the box cover flush with the surface of the finished area or such other level as directed by the owner. Valve boxes should be of such design that a traffic load on the top of the box is not transmitted to the valve. A.5.2.3 Valves buried in unusually deep trenches should have special provisions for operating the valve — either a riser on the stem to permit use of a normal key or a notation on valve records that a long key will be required. A.5.2.4 When valves with exposed gearing or operating mechanisms are installed belowground, a vault designed to allow pipe clearance and prevent settling on the pipe should be provided. The operating nut should be accessible from the top opening of the vault with a valve key. The size of the vault should provide for easy removal of the valve bonnet and internal parts of the valve for purposes of repair.

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Consideration should be given to the possible entry of groundwater and/or surface water and to the need to provide for the disposal of such water.

Sec. A.5.3 Aboveground Installation Valves installed aboveground or in a plant piping system should be supported and aligned to avoid damage to the valves. Valves should not be used to correct the misalignment of piping.

Sec. A.5.4 Inspection After installation and before pressurization of the valve, all pressure-containing bolting (bonnet, seal plate, packing gland, and end connections) should be inspected for adequate tightness to prevent leakage. In addition, an inspection should be made for adequate tightness of all tapped and plugged openings to the valve interior. Proper inspection at this time will minimize the possibility of leaks after pressurization of the piping system.

Sec. A.5.5 Testing In order to prevent time lost searching for leaks, it is recommended that valve excavations not be backfilled until after pressure tests have been made. After installation, it is desirable to test newly installed piping sections, including valves, at some pressure above the system design pressure. The test pressure should not exceed the rated working pressure of the valve. After the test, steps should be taken to relieve any trapped pressure in the body of the valve. The resilient-seated gate valve should not be operated in either the opening or closing direction at differential pressures above the rated working pressure. It should be noted that valves seat better at or near the rated working pressure of the valve. It is also recognized that wear or foreign material may damage valve seating surfaces and may cause leakage.

Sec. A.5.6 Records On completion of the installation, valve location, size, make, type, date of installation, number of turns to open, direction of opening, and other information deemed pertinent should be entered on permanent records.

Sec. A.5.7 Application Hazards Resilient-seated gate valves should not be installed in applications or for service other than those recommended by the manufacturer. A.5.7.1 Resilient-seated gate valves should not be installed in lines where service pressure will exceed the rated working pressure of the valve. A.5.7.2 Resilient-seated gate valves should not be used for throttling service unless the design is specifically recommended for that purpose or approved in advance by the manufacturer. A.5.7.3 Resilient-seated gate valves should not be used in applications that are exposed to freezing temperatures unless sufficient flow is maintained through the valve or other protection is provided to prevent freezing. A.5.7.4 Pipe, fittings, and valves installed in underground pipelines are generally joined with push-on or mechanical joints. These joints are considered unrestrained-type joints since no significant restraint against longitudinal separation is provided.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

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AWWA C509-94

Gate valves should not be installed at a dead end or near a bend in a pipeline without proper and adequate restraint to support the valve and prevent it from blowing off the end of the line. It is good engineering practice to consider during design whether or not thrust blocks, restrained joints, or other means of restraint are needed on or adjacent to valves on pipelines and/or where unusual conditions exist, such as high internal pressures, adjacent fittings, or unsuitable soils. A.5.7.5 To prevent damage, 3-in. (75-mm) and 4-in. (100-mm) NPS resilientseated gate valves should not be operated with input torques greater than 200 ft-lb (270 N⋅m). Gate valves 6 in. (150 mm) NPS to 12 in. (300 mm) NPS should not be operated with input torques greater than 300 ft-lb (406 N ⋅m).

SECTION A.6: INSPECTION AND MAINTENANCE Each valve should be operated through a full cycle and returned to its normal position on a time schedule designed to prevent a buildup of tuberculation or other deposits that could render the valve inoperable or prevent a tight shutoff. The interval of time between operations of valves in critical locations, or valves subjected to severe operating conditions, should be shorter than that for less important installations, but can be whatever time period is found to be satisfactory based on local experience. The number of turns required to complete the operation cycle should be recorded and compared with permanent installation records to ensure full gate travel. When using portable auxiliary power actuators with input torque capacities exceeding the maximum operating torques recommended in Sec. A.5.7.5, extreme care should be taken to avoid the application of excessive torque to the valve stem. If the actuator has a torque-limiting device, it should be set below the values in Sec. A.5.7.5. If there is no torque-limiting device, the recommended practice is to stop the power actuator three or four turns before the valve is fully opened or fully closed and then complete the operation manually. Maintenance should be performed at the time a malfunction is discovered to avoid a return trip to the same valve and to prevent forgetting about it altogether. A recording system should be adopted that provides a written record of valve location, condition, maintenance, and each subsequent inspection of the valve.

Sec. A.6.1 Inspection Each valve should be operated through one complete operating cycle. If the stem action is tight as a result of “hard-water” buildup on the stem threads, the operation should be repeated several times until the opening and closing actions are smooth and free. With the gate in the partially open position, a visual inspection should be performed, where practical, to check for leakage at all joints, connections, and areas of packing or seals. If leakage is observed, all defective O-rings, seals, gaskets, or end-connection sealing members should be replaced. If the leakage cannot be corrected immediately, the nature of the leakage should be reported promptly to those who are responsible for repairs. If the valve is inoperable or irreparable, its location should be clearly established to save time for repair crews. The condition of the valve and, if possible, the gate position, should be reported to personnel

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responsible for repairs. In addition, fire departments and other appropriate municipal departments should be informed that the valve is out of service.

Sec. A.6.2 Record Keeping In order to carry out a meaningful inspection and maintenance program, it is essential that the location, make, type, size, and date of installation of each valve be recorded. Depending on the type of record-keeping system used, other information may be entered in the permanent record. When a resilient-seated gate valve is inspected, an entry should be made in the permanent record indicating the date of inspection and condition of the valve. If repair work is necessary, it should be indicated. On completion of the work, the nature of the repairs and date completed should be recorded.

SECTION A.7: REPAIRS Leakage, broken parts, hard operation, and other major defects should be corrected by a repair crew as soon as possible after the defect has been reported. If repairs are to be performed in the field, the repair crews should take a full complement of spare parts to the jobsite. Provisions should be made to isolate the defective valve from water pressure and relieve internal trapped pressure prior to performing any corrective maintenance. Disassembly of the valve should be accomplished in accordance with the procedure supplied by the manufacturer. After repairing the valve, the operating mechanism should be cycled through one complete operating cycle. With full line pressure applied to the valve in the open position, an inspection should be made to detect leakage in the areas around the seal plate, bonnet, packing gland, and body-end connections. A record should be made to indicate that the valve has been repaired and is in working condition. Any markings indicating that the valve is inoperable should be removed. In addition, fire departments and other appropriate municipal departments should be informed of the satisfactory repair of the valve.

Copyright (C) 1998 American Water Works Association, All Rights Reserved.

3P-2M-43509-2/97-RM

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