METAL-SEATED GATE VALVES FOR WATER SUPPLY SERVICE

Transcription

1 American Water Works Association ANSI/AWWA C (Revision of ANSI/AWWA C500-86) R AWWA STANDARD FOR METAL-SEATED GATE VALVES FOR WATER SUPPLY SERVICE All changes specified in addendum AWWA C500a-95 are incorporated into this standard. Effective date: Mar. 1, First edition approved by AWWA Board of Directors June 24, This edition approved June 6, Approved by American National Standards Institute Dec. 8, AMERICAN WATER WORKS ASSOCIATION 6666 West Quincy Avenue, Denver, Colorado 80235

2 AWWA Standard This document is an American Water Works Association 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 Inc., 11 W. 42nd St., New York, NY 10036; (212) Copyright 1994 by American Water Works Association Printed in USA ii

3 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. R.B. Luciani, Philadelphia Water Department, Philadelphia, Pa. (NEWWA) (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. J.V. Fonley, Orange, Calif. J.J. Gemin, Proctor & Redfern Ltd., Kitchener, Ont. T.C. Jester, Consulting Engineer, Birmingham, Ala. S.J. Medlar, Camp, Dresser & McKee Inc., Edison, N.J. E.F. Straw, ISO Commercial Risk Services Inc., Duluth, Ga. G.P. Westerhoff, Standards Council Liaison, Malcolm Pirnie Inc., White Plains, N.Y. (UL) (FMRC) (NEWWA) (ISO) Producer Members Jerry Bottenfield, Clow Valve Company, Oskaloosa, Iowa G.L. Bouc, Mueller Company, Decatur, Ill. (MSS) *Liaison, nonvoting Alternate iii

4 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 iv

5 Contents All AWWA standards follow the general format indicated subsequently. Some variations from this format may be found in a particular standard. SEC. PAGE SEC. PAGE Foreword I History of Standard... vii II Field Testing and Operating Gate Valves at High Pressure... vii III Information Regarding Use of This Standard... viii IV Modification to Standard... ix V Acceptance... ix VI Major Revisions... x Standard 1 General 1.1 Scope Definitions Data to Be Supplied by Manufacturer Affidavit of Compliance References Materials 2.1 General Physical and Chemical Properties General Design 3.1 Structural Design Size of Waterway Body and Bonnet Bolting Valve Ends Gates and Rings Body-Seat Rings Disc-Spreading Devices Guides (Solid-Wedge or Split-Wedge Valves) Roller and Tracks for Horizontal Valves Stem and Stem Nut Stem Sealing Packing Packing Glands, Gland Flanges, Gland Bolts, and Gland-Bolt Nuts Wrench Nuts and Handwheels Gearing Gear Cases Indicators Bypasses Gaskets Painting and Coating Fabrication 4.1 Workmanship Testing, Inspection, and Rejection 5.1 Production Testing Plant Inspection and Rejection Marking and Shipping 6.1 Markings Preparation for Shipment Appendix A Installation, Operation, and Maintenance of Gate Valves A.1 General A.2 Unloading A.3 Inspection Prior to Installation A.4 Storage A.5 Installation A.5.1 Bolts A.5.2 Underground Installation A.5.3 Aboveground Installations A.5.4 Inspection v

6 A.5.5 Testing A.5.6 Records A.5.7 Application Hazards A.6 Inspection and Maintenance A.6.1 Inspection A.6.2 Record Keeping A.7 Repairs Tables 2 Minimum Thickness of Valve Body and Bonnet Inside Diameter (ID) of Bell Ends Excess Flange Thickness Minimum Diameter of Stem and Minimum Number of Turns to Open Diameter of Handwheels Gear Ratios Size Requirements of Bypasses Chemical and Physical Requirements for Bronze... 5 vi

7 Foreword This foreword is for information only and is not a part of AWWA C500. I. History of Standard. The first AWWA standard for gate valves was adopted June 24, It was reissued without change on June 9, 1916, as part of AWWA Standard Specifications for Hydrants and Valves. At the time of the next revision in 1938, the standard for valves was published separately. The dates of approval and numerical designation of all past editions of AWWA C500 are listed below. Dates shown in parentheses are the effective dates for use of the revised editions. Designation Date of Approval None June 24, F Apr. 29, 1939 (May 1, 1939) 7F.1-39 Feb. 25, 1943 (limitations by War Production Board) C500-52T May 9, 1952 (January 1953 except Sec. 17 and Sec. 18, which became effective June 1, 1953) C500-58T Jan. 28, 1958 (Jan. 1, 1959) C500-59T Jan. 28, 1959 C Jan. 23, 1961 C Jan. 24, 1971 C Jan. 28, 1980 C June 22, 1986 The New England Water Works Association (NEWWA) has participated with AWWA from the beginning in the development of this standard. At times, the two associations maintained separate committees that worked in close liaison with each other. At other times, NEWWA appointed representatives to the AWWA committee, as at present. The Manufacturers Standardization Society of the Valve and Fittings Industry (MSS) has played an important role in development of the standard. This organization was created in 1924, and in 1930 organized the MSS Water Works Committee and designated representatives for appointment to the AWWA Standards Committee on Gate Valves and Swing Check Valves. Available records do not reveal the part played by manufacturers in developing the 1913 standard. However, in all subsequent revisions, the MSS committee has participated effectively as have other manufacturers not represented by MSS. II. Field Testing and Operating Gate Valves at High Pressure. Field-testing limitations. AWWA C500 provides for hydrostatic pressure and leakage testing of the valves at the manufacturer s plant. If field testing of the pipe system in which valves are installed requires that the valves hold against higher pressures than their rated working pressures, the purchaser should recognize that the excess test pressure may cause seat leakage in excess of that specified in AWWA C500 and should consider this when evaluating the field-test results. It should be recognized that wear or foreign materials may damage valve seating surfaces and may cause leakage in excess of that specified in AWWA C500. In no case should the field-test pressure applied to the valves be greater than twice the lowest rated working pressure of the valves, since component parts may be excessively stressed or vii

8 deformed, nor should the valves be opened or closed during the field test against differential pressures exceeding the rated working pressures of the valves. Operation under full-flow discharge or emergency conditions. When valves larger than 12 in. (300 mm) NPS* are intended for continuous operation under fullflow discharge conditions of the magnitude that might occur when a water main breaks, with differential pressures approaching the rated pressures of the valves, special design and construction may be required. Before specifying such special design and construction, the purchaser should review the operating conditions and special requirements with the valve manufacturer. III. 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, a number of items must be specified to completely describe the valve required. The following summarizes the items the purchaser should cover in the specifications and lists the sections in the standard where the items are discussed. 1. Standard used that is, AWWA C500-93, Standard for Metal-Seated Gate Valves for Water Supply Service. 2. Size and type of valve (Sec. 1.1). 3. Quantity required. 4. Direction in which handwheel or wrench nut shall turn to open (Sec ). 5. Intended position of valve (Sec. 1.1). 6. Catalog data, net weight, and assembly drawings to be furnished by the manufacturer (Sec. 1.3). 7. Affidavit of compliance (Sec. 1.4) if required. 8. If records of tests specified in Sec. 2.2 and Sec. 5.1 are to be furnished. 9. If the piping system in which the valve or valves are to be used carries water that promotes galvanic corrosion and requires the use of alternative materials, as described in Sec What rustproofing alternative, for bolts and nuts if any, is desired (Sec. 3.4 and Sec ). 11. Type of valve ends bell (Sec ), flanged (Sec ), tapping-valve flange (Sec ), or mechanical joint (Sec ) or push-on joint (Sec ). 12. Bell dimensions or outside diameter of pipe for valves 16 in. (400 mm) NPS or larger (Sec ) if deviating from Table 3 of this standard. 13. Spot facing if required (Sec ). 14. Orientation of the bolt holes in mechanical-joint flanges (Sec ). The common practice is to have the bolt holes straddle the vertical centerlines of valves, fittings, and hydrants. If another orientation is known to be necessary, it should be specified. 15. Solid bronze discs (gates) if required (Sec ). 16. Method of fastening gate rings if not in accordance with Sec Type of stem seal stuffing box or O-ring (Sec. 3.12). 18. Detailed description of wrench nuts and handwheels if the ones used are not in accordance with Sec *Nominal pipe size. viii

9 19. Gears if required (Sec. 3.16). 20. Cast-iron gears if required (Sec ). 21. Type of gear case to be furnished extended type or totally enclosed type (Sec. 3.17). 22. Position indicator if required (Sec. 3.18). 23. Bypass if required (Sec. 3.19), and its location. 24. Special cast markings if required (Sec. 6.1). 25. If the hydrostatic test at twice the rated pressure is to be held for a specified period of time (Sec ). 26. If a special interior or exterior coating is required (Sec. 3.21). 27. If bolting material with physical and chemical properties other than ASTM* A307, Standard Specification for Carbon Steel Bolts and Studs, 60,000 psi Tensile Strength, is required (Sec. 3.4). It is recommended that the purchaser verify with the supplier the appropriateness of any alternative bolting materials required. 28. Cutter diameter must be specified for tapping valves (Sec. 3.2). At the time this edition of AWWA C500 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 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 C should comply with USEPA, state, provincial, and local actions regarding asbestos and consider the implications of using various alternative gasket and packing materials as listed in this standard. IV. Modification to Standard. Any modification of the provisions, definitions, or terminology in this standard must be provided in the purchaser s specifications. V. Acceptance. In May 1985, the USEPA entered into a cooperative agreement with a consortium led by NSF International (NSF) to develop voluntary thirdparty 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, 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, Specific policies of the state or local agency. *American Society for Testing and Materials, 1916 Race St., Philadelphia, PA Persons in Canada, Mexico, and non-north American countries should contact the appropriate authority having jurisdiction. ix

10 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. 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 C 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. VI. Major Revisions. The major revisions in this edition of AWWA C500 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 ). *American National Standards Institute, 11 W. 42nd St., New York, NY NSF International, 3475 Plymouth Rd., Ann Arbor, MI Both publications available from National Academy of Sciences, 2102 Constitution Ave. N.W., Washington, DC x

11 American Water Works Association R ANSI/AWWA C (Revision of ANSI/AWWA C500-86) AWWA STANDARD FOR METAL-SEATED GATE VALVES FOR WATER SUPPLY SERVICE SECTION 1: GENERAL Sec. 1.1 Scope This standard covers iron-body, bronze-mounted, nonrising-stem (NRS) gate valves including tapping gate valves, 3 in. (75 mm) NPS through 48 in. (1200 mm) NPS,* and outside screw and yoke (OS&Y) rising-stem gate valves, 3 in. (75 mm) NPS through 12 in. (300 mm) NPS, with either double-disc gates having parallel or inclined seats, or solid-wedge gates. These valves are suitable for use in approximately level settings in water systems Valve pressure ratings. The design working water pressure shall be 200 psig (1380 kpa) for valves 12 in. (300 mm) NPS and smaller, and 150 psig (1050 kpa) for valves with diameters of 16 in. (400 mm) NPS and larger. Valves for operating pressures that fall outside these limits are beyond the scope of this standard and require special consideration in design and construction Conditions and materials not covered. This standard is not intended to cover special conditions of gate-valve installation or operation, such as built-in power drive, installation in vertical or steeply inclined lines, conveyance of unusually corrosive water, excessive water hammer, frequent operation (as in filter service), or operation in a throttled position. 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. *Valves 14 in. (350 mm) NPS and 18 in. (450 mm) NPS are not considered standard-size valves and are not covered by this standard. 1

12 2 AWWA C Sec. 1.2 Definitions In this standard, the following definitions shall apply: Cosmetic defect: A blemish that has no effect on the ability of a component to meet the structural design and production test requirements of this standard. If the blemish or the activity of plugging, welding, grinding, or repairing the blemish causes the component to fail these requirements, then the blemish shall be considered a structural defect Flanged joint: The flanged and bolted joint as detailed in ANSI/AWWA C110/A21.10 or ANSI B16.1, class Hub-end (bell-and-spigot) joint: The poured or caulked joint as described in Sec Manufacturer: The party that manufactures, fabricates, or produces materials or products Mechanical joint: The gasketed and bolted joint as described in ANSI/AWWA C111/A NPS: Nominal pipe size Purchaser: The person, company, or organization that purchases any materials or work to be performed Push-on joint: The single rubber gasket joint as described in ANSI/AWWA C111/A Structural defect: A flaw that causes a 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 minimum wall thickness requirement, or failure to meet production tests Tapping valves: 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 Data to be Supplied by Manufacturer If requested by the purchaser, the manufacturer shall furnish the following information when filling orders for gate valves Catalog data. The manufacturer shall supply catalog data, including illustrations and a parts schedule that identifies the materials to be used for making various parts. This information shall be in sufficient detail to serve as a guide for assembly and disassembly of the valve and for ordering parts Weight information. The manufacturer shall furnish a statement of the net assembled weight for each size of valve exclusive of joint accessories 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 valves shall be furnished in accordance with these drawings after the drawings have been reviewed and accepted by the purchaser. Sec. 1.4 Affidavit of Compliance The manufacturer shall, when required by the purchaser s specifications, furnish the purchaser with an affidavit that the valve and all materials used in its construction conform to the applicable requirements of this standard and the specifications, and that all tests specified therein have been performed and all test requirements have been met.

13 METAL-SEATED GATE VALVES 3 Sec. 1.5 References Aerospace Standard* AS-568A Aerospace Size Standard for O-rings. ANSI B16.1 Cast Iron Pipe Flanges and Flanged Fittings Class 25, 125, 250 and 800. ANSI B Square and Hex Bolts and Screws Including Askew Head Bolts, 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 A165 Specification for Electrodeposited Coatings of Cadmium on Steel (discontinued). ASTM A307 Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength. ASTM A395 Standard Specification for Ferritic Ductile Iron Pressure- Retaining Castings for Use at Elevated Temperatures. ASTM A536 Standard Specification for Ductile Iron Castings. ASTM B154 Standard Test Method of Mercurous Nitrate Test for Copper and Copper Alloys. ASTM B584 Standard Specification for Copper Alloy Sand Castings for General Applications. 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 D471 Standard Test Method for Rubber Property Effect of Liquids. ASTM D1149 Standard Test Method for Rubber Deterioration-Surface Ozone Cracking in a Chamber (Flat Specimen). 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., for Water and Other Liquids. ANSI/AWWA C111/A21.11 American National Standard for Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings. ANSI/AWWA C509 Standard for Resilient-Seated Gate Valves for Water and Sewerage Systems. ANSI/AWWA C550 Standard for Protective Epoxy Interior Coatings for Valves and Hydrants. *Aerospace Standard available from Society of Automotive Engineers, 400 Commonwealth Dr., Warrendale, PA American National Standards Institute, 11 W. 42nd St., New York, NY American Society for Testing and Materials, 1916 Race St., Philadelphia, PA

14 4 AWWA C 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. 2.1 General SECTION 2: MATERIALS 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 to which references are made 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 or supplier. The records of all tests shall, if required by the purchaser s specification, be made available to the purchaser Gray iron. Gray iron shall equal or exceed the requirement of ASTM A126 class B Ductile iron. Ductile iron shall conform to one of the following standards: ASTM A395 or ASTM A Brass or bronze. Brass or bronze used in valves shall comply with the following: Valve components of brass or bronze shall be made to ASTM or Copper Development Association (CDA) recognized alloy specifications The chemical and physical requirements shown in Table 1 shall apply 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 Waters in some areas have been shown to promote galvanic corrosion in the form of dezincification or dealuminization. In such waters, grade B and grade C bronze shall not be used. If aluminum bronze is used, the alloys shall be inhibited against dealuminization by proper application of a temper anneal or other suitable means. *Federal Specification available from Naval Publications and Forms Center, 5801 Tabor Ave., Philadelphia, PA Manufacturers Standardization Society of the Valve and Fittings Industry Inc., 127 Park St. N.E., Vienna, VA Copper Development Association, 405 Lexington Ave., New York, NY

15 METAL-SEATED GATE VALVES 5 Table 1 Chemical and physical requirements for bronze Minimum Yield Minimum elongation Minimum Maximum Grade Strength in 2 in. (50.8 mm)* Copper Zinc of Bronze psi (kpa) % % % A 14,000 (96,500) B 20,000 (137,800) C 32,000 (220,500) D 20,000 (137,800) E 32,000 (220,500) *Gauge length of sample Bronze components that contact drinking water shall not contain more than 8 percent lead. (US Safe Drinking Water Act Amendments of 1986.) Steel. Carbon-steel castings, when used, shall be ASTM A27 grade U or equal Elastomers. Elastomers shall comply with the following: Rubber shall be resistant to microbiological attack, copper poisoning, and ozone attack Rubber compounds shall contain no more than 8 ppm (parts per million) of copper ion and shall include copper inhibitors to prevent copper degradation of the rubber material Rubber compounds shall be capable of withstanding an ozone resistance test when tested in accordance with ASTM D1149. The tests shall be conducted on the unstressed samples for 70 h at 104 F (40 C) with an ozone concentration of 50 pphm (parts per hundred million), and there shall be no visible cracking in the surfaces of the test samples after tests Rubber 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) Rubber compounds shall contain no more than 1.5 parts of wax per 100 parts of rubber hydrocarbon and shall have less than a 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 Rubber compounds shall be free from vegetable oils, vegetable-oil derivatives, animal fats, and animal oils 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 O-rings. O-rings shall meet the requirements of ASTM D2000 and have physical properties suitable for the application Coatings. Unless otherwise specified by the purchaser, valve coatings (as specified in Sec. 3.21) shall at a minimum conform to Federal Specification TT-C-494b or AWWA C550.

16 6 AWWA C 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 water pressure of the valve and (2) the full rated internal working pressure when the wedge or gates are moved across the seats, under full unbalanced working water pressure from the fully closed position to the point of opening, then to complete closure. In addition to these pressure requirements, the valve assembly and mechanism shall be capable of withstanding an input torque as follows: 3 in. (75 mm) NPS and 4 in. (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. All parts, including the body and bonnet, shall be proportioned so that the valve body or bonnet shall not fail if excessive torque is applied to the stem in the closing direction with the valve-disc seated and subjected to the working water pressure. 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, except that if lugs are provided for inserting or removing the body-seat rings, they need not be removed after the valve is assembled. For tapping valves, the size of the waterway shall include appropriate clearance for the diameter of the tappingmachine cutter recommended by the valve manufacturer. Sec. 3.3 Body and Bonnet Shell thickness. The body and bonnet of valves shall be made of gray iron or ductile iron and shall comply with the requirements of Sec Shellthickness measurements taken at points diametrically opposite to each other shall, when added together and divided by 2, equal or exceed the minimum metal thicknesses given in Table 2. At no point shall shell thicknesses be more than 12.5 percent thinner than the minimum metal thicknesses shown in Table 2. No continuous area of deficient thickness shall exceed 12.5 percent of the pressurecontaining shell area of the casting Metal sections. All metal sections and ribbing shall be properly proportioned, and corners shall have well-rounded fillets in accordance with good foundry practice. In double-disc valves, the body and bonnet shall be designed to minimize the side clearance of the discs Seating surfaces. The valve body shall be machined and threaded for shoulder-seated (or bottom-seated) body-seat rings, and the thread shall be sufficiently deep and the seating surface sufficiently accurate to prevent leakage behind the body-seat rings Thrust bearings. The thrust-bearing recess and the stem opening (if the opening is in contact with the stem) in the bonnet shall be machined or finished in a manner that will provide a surface that is smooth and either parallel or perpendicular to the stem axis within 0.5 or less. In valves 16 in. (400 mm) NPS and larger, the thrust-bearing surface shall be grade A, B, C, D, or E bronze, and the stem

17 METAL-SEATED GATE VALVES 7 Table 2 Minimum thickness of valve body and bonnet Valve Diameter Minimum Thickness* NPS, in. (mm) in. (in. fractions) (mm) 3 (75) 0.37 ( 3 8 ) (9) 4 (100) 0.40 ( ) (10) 6 (150) 0.43 ( 7 16 ) (11) 8 (200) 0.50 ( 1 2 ) (13) 10 (250) 0.63 ( 5 8 ) (16) 12 (300) 0.68 ( ) (17) 16 (400) 0.85 ( ) (22) 20 (500) 0.97 ( ) (25) 24 (600) 1.08 ( ) (27.4) 30 (750) 1.39 ( ) (35.3) 36 (900) 1.54 ( ) (39.1) 42 (1050) 1.58 ( ) (40.1) 48 (1200) 1.73 ( ) (43.9) *The decimal value should be used when the two expressions are not exactly equivalent. Sec. 3.4 Bolting Sec. 3.5 Valve Ends opening shall be grade A, B, C, D, or E bronze bushed if the opening is in contact with the stem Doweling. In horizontal-stem valves 16 in. (400 mm) NPS and larger, and in vertical-stem valves 24 in. (600 mm) NPS and larger, a pair of accurately matched dowel holes and tapered or round-end dowels shall be provided in the flanges of the body and bonnet to aid in assembling. Dowels shall be located at opposite ends of the flange one near the lateral centerline and the other approximately 2 in. (50 mm) from the lateral centerline Yokes for 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 Stem opening on OS&Y valve. 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 on the underside or otherwise designed to make a joint with the stem or stem nut when the gate is wide open. 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 B 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 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. End connections for bell and spigots, flanges, and mechanical joints shall conform to the following requirements: Bell ends for caulked joints.

18 8 AWWA C The dimensions of the bell on valves up to and including 12 in. (300 mm) NPS shall conform to those for bell-and-spigot fittings specified in ANSI/AWWA C110/A For valves 16 in. (400 mm) NPS and larger, the bell dimensions shall conform to those for bell-and-spigot fittings specified in ANSI/AWWA C110/A21.10 except for the bell diameters For valves 3 in. (75 mm) NPS through 24 in. (600 mm) NPS, the inside diameter shall be as shown in Table For valves 16 in. (400 mm) NPS and larger, the inside bell diameter of the valve or the outside diameter of the pipe to be used shall be specified in the purchaser s specifications if the dimensions deviate from those provided in Table Flanged ends. The end flanges of flanged valves shall conform in dimensions and drilling to 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 indicated in Table 4 or if the flange is not sufficiently flat. Table 3 Inside diameter (ID) of bell ends Size of Valve ID of Bell* NPS, in. (mm) in. (mm) 3 (75) 4.66 (118.36) 4 (100) 5.70 (144.78) 6 (150) 7.80 (198.12) 8 (200) (254.00) 10 (250) (307.34) 12 (300) (360.68) 16 (400) (477.52) 20 (500) (585.72) 24 (600) (693.93) 30 (750) (856.99) 36 (900) ( ) 42 (1050) ( ) 48 (1200) ( ) *The listed dimensions for 30 in. (750 mm) NPS through 48 in. (1200 mm) NPS are the same as those formerly specified for class D cast-iron pressure fittings. Table 4 Excess flange thickness Nominal Valve Size Excess Thickness (minimum) NPS, in. (mm) in. (mm) 3 12 (75 300) 1 8 (3.2) ( ) 3 16 (4.8) ( ) 1 4 (6.4)

19 METAL-SEATED GATE VALVES 9 If the above-mentioned limits are exceeded, either spot-facing or back-facing may be used to meet these 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 Tapping-valve flange ends 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 The connecting flange of the tapping valve mating with the tapping machine must be parallel and concentric with the opposite flange and seat rings to provide proper alignment for the tapping operation Mechanical-joint ends. Mechanical-joint bell dimensions shall conform to ANSI/AWWA C111/A Instead of holes in the bell flange, slots with the same width as the diameter of the bolt holes may be provided at those places where the valve body and bonnet interfere with the joint assembly Push-on joint ends. Push-on joints shall conform to the requirements of ANSI/AWWA C111/A Sec. 3.6 Gates and Rings Valve gates. Valve gates shall be cast iron or grade A bronze at the manufacturer s option, unless bronze is explicitly required by the purchaser s specifications Gate rings. Gate rings shall be made of grade A bronze. Gate rings shall be rolled, peened, or pressed into grooves machined in the discs or fastened by some other method disclosed and acceptable to the purchaser. The rings shall be made with a cross section stiff enough to resist accidental deformation during handling and assembly The gate-ring faces shall be machine finished after they have been fully secured in place The width of the faces of the gate rings shall not be less than that of the body-seat rings, and shall be sufficiently greater in width to permit the gates to continue to seat tightly after allowance for reasonable wear. Sec. 3.7 Body-Seat Rings Material and finish. The rings shall be back-faced, with threads accurately cut, and shall be screwed into machined seats in the body. The face in contact with the gate-seat ring shall be smooth and machine finished. Body-seat rings shall be made of grade A bronze with a cross section stiff enough to resist accidental deformation during handling and assembly and shall be smooth Width. The width of body-seat rings shall be sufficient to result in a bearing pressure of the gate on the body-seat ring of not more than 2000 psi (13.8 MPa) under a hydrostatic pressure of 300 psi (2070 kpa). The thickness of the body-seat ring shall not be less than 20 percent of the width of the face as calculated from the above width requirement. Sec. 3.8 Disc-Spreading Devices Valves of the double-disc type shall be equipped with a free and positiveoperating internal device, simple and rugged in design, that will press the disc seats

20 10 AWWA C firmly against the body seats when the valve is closed and release the load therefrom before the discs start to move when the valve is opened Material. Bronze used for wedges shall be grade A, B, C, D, or E. Pins and bolts in the wedging mechanism of all valves shall be grade A, B, C, D, or E bronze. For valves 16 in. (400 mm) NPS and larger, all wedging surfaces shall be grade A, B, C, D, or E bronze to bronze. For valves with diameters of 3 12 in. ( mm) NPS inclusive, all wedging surfaces may be grade A, B, C, D, or E, bronze to iron, but not iron to iron Alternative materials. As an alternative to bronze, wedging surfaces on valves 12 in. (300 mm) NPS and smaller may be nickel alloy, in accordance with ASTM B584, or 300-series stainless steel to iron. For valves 16 in. (400 mm) NPS and larger, both wedging surfaces may be nickel alloy, in accordance with ASTM B Rubber materials. Rubber used in a disc-spreading device shall be a compound as per Sec , with mechanical properties as required. Sec. 3.9 Guides (Solid-Wedge or Split-Wedge Valves) In solid-wedge or split-wedge valves, tongue-and-groove guides shall be provided on the sides of the gate and in the body to keep the gate centered between the seats throughout its length of travel Material. For valves 16 in. (400 mm) NPS and larger, the guide contacts shall be grade A, B, C, D, or E, bronze to bronze Bearing surfaces. For valves 16 in. (400 mm) NPS and larger, bearing surfaces between the gates and the guides each shall have a length equal to at least 50 percent of the port diameter of the valves. Sec Roller and Tracks for Horizontal Valves Double-disc valves. Valves of the double-disc type, 16 in. (400 mm) NPS and larger, designed to lie horizontally in a horizontal pipeline, shall be equipped with solid bronze, grade A, B, or D; or 300-series stainless-steel tracks securely fastened in body and bonnet. The weight of the gates shall be carried on roller(s) throughout their entire length of travel For double-disc valves of the rolling-disc type, the discs shall serve as roller(s) For double-disc valves of other than the rolling-disc type, the discs shall be carried on solid bronze, grade A, B, C, D, or E roller(s) securely attached to them Scrapers. For all valves using roller(s) and track(s), bronze scrapers grade A, B, C, D, or E shall be provided to traverse the track(s) ahead of the roller(s) in both directions of travel to remove any foreign matter accumulated on the track(s). Sec Stem and Stem Nut Stem collars. All stem collars shall be made integral with stems on NRS valves. The stems 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. This backseat should allow repacking per Sec Threads. The threads of stems and stem nuts (disc bushing) shall be of Acme, modified Acme, or one-half V-type.

21 METAL-SEATED GATE VALVES 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 Diameter. The stem diameters and turns to open shall be as shown in Table 5. The diameter of the stem at the base of the thread or at any point below that portion shaped to receive the wrench nut or gear on NRS valves, or the minimum diameter of the stem unthreaded section and thread outside diameter for OS&Y valves, shall not be less than specified OS&Y stems. OS&Y valve stems shall be of sufficient length to be at least flush with the top of the yoke nut after the disc wedging has been worn into its lowest position. The design shall be such to prevent any possibility of the wedge or disc leaving the stem or the stem turning during the operation of the valve Materials. Valve stems shall be cast, forged, or rolled bronze. Bronze for valves sized 24 in. (600 mm) NPS and smaller shall be grade B, C, D, or E, and grade C or E for valves sized 30 in. (750 mm) NPS and larger. Stem nuts shall be grade A, B, C, D, or E bronze 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. Table 5 Minimum diameter of stem and minimum number of turns to open OS&Y Valves NRS Valves Minimum Diameter of Minimum Minimum Stem Unthreaded Minimum Diameter of Stem Number of Section and Number of Valve Size (at base of thread) Turns of Stem Thread OD* Turns of Stem NPS, in. (mm) in. (mm) to Open in. (mm) to Open 3 (75) (21.82) (19.1) 7 4 (100) (21.82) 12 1 (25.4) 9 6 (150) (25.40) (28.6) 20 8 (200) (25.40) (31.8) (250) (28.58) (34.9) (300) (30.18) (34.9) (400) (36.53) (500) (44.45) (600) (50.01) (750) (55.58) (900) 2.50 (63.5) (1050) 2.75 (69.9) (1200) 3.50 (88.9) 96 *Outside diameter. Valves shown for 6 12 in. ( 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. ( mm) NPS inclusive.

22 12 AWWA C Sec Stem Sealing Sec Packing The 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 Stuffing boxes. Design of the stuffing box shall be such that the valve can be packed under pressure when in the fully open position For NRS valves, the stem opening, thrust-bearing recess, and bonnet face of the stuffing box shall be machined or finished in a manner that will provide a surface that is smooth and either parallel or perpendicular to the stem axis within 0.5. For valves 16 in. (400 mm) NPS and larger, both the stem opening and thrustbearing surface shall be bronze bushed 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 O-rings. O-rings shall meet the requirements of ASTM D2000 and have physical properties suitable for the application. When an O-ring or other pressureactuated stem seal is used, the design shall incorporate two such seals, the dimensions of such seals to be in accordance with AS-568A The sealing systems shall be designed to remain watertight at pressures required by this standard The valve shall be designed so that the seal above the stem collar can be replaced when the valve is under pressure and in the fully open position Material. Stuffing-box packing shall be made of flax that conforms to Fed. Spec. HH-P-106d or other appropriate material. Hemp, asbestos, or jute packing shall not be used Installation. Stuffing boxes shall be properly packed and ready for service when valves are delivered to the purchaser. Adjustment of stuffing-box bolts may be required to seal leakage at time of installation. Sec 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 Material. Packing glands for valves of size 12 in. (300 mm) NPS and smaller shall be made of grade A, B, C, D, or E bronze. Packing glands for valves of sizes larger than 12 in. (300 mm) NPS may be made of cast iron with bushings of grade A, B, C, D, or E bronze 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 Packing-gland bolts. Packing-gland bolts shall be made either of grade B, C, D, or E bronze or rustproofed steel according to Sec Gland-bolt nuts shall be made of grade B, C, D, or E bronze.

23 METAL-SEATED GATE VALVES 13 Table 6 Diameter of handwheels* Size of Valve Minimum Diameter of Handwheel NPS, in. (mm) in. (mm) 3 (75) 7 (178) 4 (100) 10 (254) 6 (150) 12 (305) 8 (200) 14 (356) 10 (250) 16 (406) 12 (300) 16 (406) *For sizes larger than 12 in. (300 mm), consult the manufacturer. Sec Wrench Nuts and Handwheels Sec Gearing 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 in. (49.2 mm) square at the top, 2 in. (50.8 mm) square at the base, and in. (44.5 mm) high. The outside diameters of handwheels shall not be less than those given in Table 6. 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 clearly indicate the direction to turn the wrench when opening the valve. Handwheels shall be of the spoke type only. Webbed or disc type 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 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 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 on NRS valves Method of securing. Wrench nuts shall be fitted to the top of the valve stem and secured in position by mechanical means 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 Color coding. Wrench nuts and handwheels that open the valves 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. If they are 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.

24 14 AWWA C Table 7 Gear ratios Valve Diameter NPS, in. (mm) Minimum Gear Ratio 16 (400) 2:1 20 (500) 2:1 24 (600) 2:1 30 (750) 3:1 36 (900) 3:1 42 (1050) 4:1 48 (1200) 4:1 Sec Gear Cases Sec Indicators Sec Bypasses* Sec Gaskets Material. Geared valves shall be equipped with steel gears unless castiron gears are explicitly required by the purchaser s specifications. Pinion shall be made of steel. Material for steel gears shall be ASTM A27 grade U or equal Gear ratio. Gear ratios shall not be less than those shown in Table 7. 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 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. 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. When required by the purchaser s specifications, bypasses shall be of the sizes shown in Table 8 unless specified otherwise. Bypass valves shall be of the same size as the bypass and shall conform to the requirements of this standard or ANSI/AWWA C509. Bypasses may be of integral or bolted construction. Gaskets, O-rings, or other suitable elastomeric seals shall be used on all flanged joints intended to be watertight. *Bypass valves may be recommended on valves 16 in. (400 mm) NPS and larger for the following reasons: (1) to equalize pressure across the closure member to permit lower operating forces during opening and closing; (2) to fill lines downstream of the main valve, thereby eliminating the possibility of wire drawing damage to main-valve seats; and (3) to provide for low-volume flow without throttling the main valve.

25 METAL-SEATED GATE VALVES 15 Table 8 Size requirements of bypasses Valve Diameter Bypass Diameter NPS, in. (mm) in. (mm) ( ) 3 (75) ( ) 4 (100) ( ) 6 (150) 48 (1200) 8 (200) Sec Painting and Coating The coating as specified in Sec shall be applied to the ferrous parts of the valves except for finished or bearing surfaces. Surfaces shall be clean, dry, and free from rust and grease before painting. The coating shall be applied to both the inside and outside ferrous metal. A coating conforming to ANSI/AWWA C550 may be used on the interior and/or exterior ferrous surfaces. Sec. 4.1 Workmanship SECTION 4: FABRICATION 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 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. SECTION 5: TESTING, INSPECTION, AND REJECTION Sec. 5.1 Production Testing After manufacture, each valve shall be subjected to operation and hydrostatic tests at the manufacturer s plant as specified in this section Operation test. To ensure free and proper functioning of all parts in the intended manner, each valve shall be operated through a complete cycle in the position for which it was designed. All defects in workmanship or materials shall be corrected and the test repeated until satisfactory performance is demonstrated Hydrostatic test. Each valve shall be subjected to hydrostatic testing For double-disc valves, a hydrostatic test pressure equal to twice the rated working pressure of the valve shall be applied between the discs, and if

26 16 AWWA C required by the purchaser s specifications, held for the specified period of time. This test shall show no leakage through the metal, flanged joints, or stem seals. Subsequently, a test shall be made at the rated working pressure, applied between the discs. This second test shall show no leakage through the metal, flanged joints, or stem seals. The leakage past either seat shall not exceed a rate of 1 oz/h/in. (1.2 ml/h/mm) of nominal valve size For solid-wedge valves, a hydrostatic pressure equal to twice the rated working pressure of the valve shall be applied with both ends bulkheaded and the gate open, and if required by the purchaser s specifications, held for the specified period of time. This test shall show no leakage through the metal, flanged joints, or stem seals. Subsequently, a test shall be made at the rated working pressure, applied (through bulkheads) alternately to each side of the closed gate with the opposite side open for inspection. This second test shall show no leakage through the metal, flanged joints, or stem seals. The leakage past either seat shall not exceed a rate of 1 oz/h/in. (1.2 ml/h/mm) of nominal valve size. Sec. 5.2 Plant Inspection and Rejection All work performed under this standard 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 that may be determined as not conforming to the requirements of this standard 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. 1.4 of this standard. Sec. 6.1 Markings SECTION 6: MARKING AND SHIPPING 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 150W for in. ( mm) NPS valves and 200W for 3 12 in. ( mm) NPS valves. Special markings in addition to these can be supplied when specified by the purchaser s requirements and on agreement between purchaser and manufacturer. Sec. 6.2 Preparation for Shipment Valves shall be complete in all details when shipped. The manufacturer shall use reasonable care in preparing them for shipment. Valves shall be drained and completely closed before shipment. Valves 24 in. (600 mm) NPS and larger shall be securely bolted or otherwise fastened to skids in such a manner that they may be safely unloaded.

27 APPENDIX A Installation, Operation, and Maintenance of Gate Valves This appendix is for information only and is not a part of AWWA C500. SECTION A.1: GENERAL Gate valves are a significant component in many fire-fighting or water distribution systems. Failure due to faulty installation or improper maintenance of a gate valve in such systems could result in extensive damage and costly repairs. In addition, many gate valves are installed in buried service or underground applications. Problems or malfunctions in these valves due to faulty installation or improper maintenance can result in extensive and costly unearthing operations in order to effectively correct the problem. Many 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. The valve should be carefully lowered from the truck to the ground, not 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. Do not hook hoists into or fasten chains around bypasses, 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 Valves should be inspected at the time of receipt for damage in shipment. The initial inspection should verify compliance with specifications, directions of opening, size and shape of operating nut, number of turns, and type of end connections. A visual inspection of the bronze gate rings and body rings 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 cycled through one complete opening-and-closing cycle in the position in which it is to be installed. 17

28 18 AWWA C SECTION A.4: STORAGE Valves should be stored in the fully closed position to prevent 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 operating mechanisms, such as gears, motor, actuators, and cylinders, from weather elements. During outside storage, valves should be protected from the weather, sunlight, ozone, and foreign material. 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 gates tightly before storage. Failure to do so may result in a cracked valve casting. Valves in outside storage in cold climates should be stored with the discs in a vertical position. If the discs are in a horizontal flat position, rainwater can accumulate on top of the top disc, seep into the valve body cavity, and freeze and crack the casting. Sec. A.5.1 Bolts SECTION A.5: INSTALLATION Instructions supplied by the manufacturer 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 valve should be removed. A detailed inspection of the valve as outlined in Sec. A.3 should be performed prior to installation. 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 Where practical, valves in water distribution lines shall be located in unpaved areas unless otherwise shown on the plans or specifications. A During installation there is the possibility of foreign material inadvertently entering the valve. Foreign material can damage internal working parts or score gate rings and body seat rings during operation of the valve. For this reason, valves should be installed in the closed position. The 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 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 as directed by the purchaser. Larger valves using smaller bypass valves should have a second box similarly installed over the bypass-valve operating nut. Valve boxes should be designed so that a traffic load on the top of the box cannot be transmitted to the valve. A Valves buried in unusually deep trenches should have special provisions for their operation either a riser on the stem to permit a normal key to be used or a notation on valve records that a long key will be required for operation.

29 METAL-SEATED GATE VALVES 19 A When valves with exposed gearing or operating mechanisms are installed below ground, 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 repair purposes. Consideration should be given to the possible entry of groundwater and/or surface water and the need to provide for the disposal thereof. Sec. A.5.3 Aboveground Installations Sec. A.5.4 Inspection Sec. A.5.5 Testing Sec. A.5.6 Records Valves installed aboveground or in plant piping systems should be supported and aligned to avoid damage to the valves. They should not be used to correct misalignment of piping. After installation and before pressurization of the valve, all pressure-containing bolting (bonnet, seal-plate, packing-gland bypass, 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. In order to save time in 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 pressures should not exceed twice the rated working pressure of the valve. After this test, steps should be taken to relieve any trapped pressure in the body of the valve. The valve should not be operated in either the opening or closing direction at differential pressures above the rated working pressure. Test pressures above the rated working pressure may cause leakage past the disc in excess of that specified in Sec of AWWA C500. 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 in excess of that specified in AWWA C500. 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 a permanent record. Sec. A.5.7 Application Hazards Valves should not be installed in applications or for service other than those recommended by the manufacturer. A Valves should not be installed in lines where service pressures will exceed the rated working pressure of the valve. A Gate valves should not be used for throttling service unless the design is specifically recommended for that purpose in advance by the manufacturer. A Double-disc valves should not be installed inverted or with the stems sloped more than 45 from the upright position unless the valve was ordered and manufactured specifically for this orientation.

30 20 AWWA C A Valves should not be used in applications where they are exposed to freezing temperatures unless sufficient flow is maintained through the valve or other protection is provided to prevent freezing. A 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. 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 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 pressure, adjacent fittings, or unsuitable soils. A To prevent damage, 3-in. (75-mm) NPS and 4-in. (100-mm) NPS valves should not be operated with input torques greater than 200 ft-lb (270 N m). Valves 6 in. (150 mm) NPS through 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 Sec. A.6.1 Inspection 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 would render the valve inoperable or prevent a tight shutoff. The interval of time between operations of large-diameter valves, valves in critical locations, or valves subjected to severe operating conditions should be shorter than for other less important installations, but can be for whatever period is shown to be satisfactory based on local experience. The number of turns required to complete the operation cycle should be recorded and then compared with permanent installation records to ensure full disc travel. When using portable auxiliary power actuators with input torque capacities exceeding the maximum operating torques recommended in Sec. A.5.7.6, extreme care should be exercised to avoid 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 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, 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 to provide a written record of (1) valve location, (2) condition, and (3) maintenance corrective action on installation and each subsequent inspection of the valve. 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 action is smooth and free. With the discs 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,

31 METAL-SEATED GATE VALVES 21 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 responsible for repairs. If the valve is inoperable or irreparable, its location should be clearly marked to save time for repair crews. The condition of the valve and, if possible, the disc position, should be reported to the proper parties 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 used, other information may be entered in the permanent record. When a 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, and on completion, the nature of the repairs and date completed should be correctly 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 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 repair of 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.

32 1P-13M /94-MG Printed on recycled paper.