REDUCED-PRESSURE PRINCIPLE BACKFLOW PREVENTION ASSEMBLY

Transcription

1 American Water Works Association ANSI/AWWA C (Revision of ANSI/AWWA C511-92) R AWWA STANDARD FOR REDUCED-PRESSURE PRINCIPLE BACKFLOW PREVENTION ASSEMBLY Effective date: Feb. 1, First edition (AWWA C506) approved by AWWA Board of Directors Jan. 27, This edition approved June 15, Approved by American National Standards Institute Dec. 2, 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, 11 W. 42nd St., New York, NY 10036; (212) Copyright 1998 by American Water Works Association Printed in USA ii

3 Committee Personnel The AWWA Standards Committee on Backflow Preventers, which reviewed and approved this standard, had the following personnel at the time of approval: James T. Cowgill, Chair Richard A. Coates, Secretary Consumer Members P.J. Brady, Department of Public Utilities, County of Henrico, Richmond, Va. S.A. Brook, Orange County Public Utilities, Orlando, Fla. E.J. Havlina, Los Angeles Department of Water and Power, Los Angeles, Calif. O.J. Jones, Cincinnati, Ohio C.L. Nena, California Water Service Company, Montebello, Calif. P.W. Orvin, City of Jacksonville, Jacksonville, Fla. General Interest Members G.J. Angele Sr., Oak Ridge, Tenn. S.F. Asay, Stuart F. Asay & Associates, Westminster, Colo. T.K. Bsharat, National Fire Sprinkler Association, Patterson, N.Y. R.A. Coates, Hazen & Sawyer, Miami, Fla. J.T. Cowgill, Hazen & Sawyer, Hollywood, Fla. H.D. Hendrickson, Water Service Consultants Inc., Exeter, N.H. K.W. Kells, * Council Liaison, Connecticut Water Company, Clinton, Conn. F.E. Kenney Jr., NEWWA, Milford, Mass. John Phillips, WSSC, Laurel, Md. E.S. Ralph, * Standards Engineer Liaison, AWWA, Denver, Colo. R.W. Rivard, Connecticut Department of Public Health, Hartford, Conn. P.H. Schwartz, University of Southern California, Los Angeles, Calif. G.R. Stiles, Seattle, Wash. R.C. Williams, ATSDR/DHAC, Atlanta, Ga. (NEWWA) (NEWWA) (CDC) Producer Members R.H. Ackroyd, Watts Regulator Company, Lawrence, Mass. P.H. Ahearn, Conbraco Industries Inc., Matthews, N.C. J.L. Brewer, CMB Industries-Febco, Fresno, Calif. *Liaison, nonvoting Alternate iii

4 Les Engelmann, Ames Company Inc., Woodland, Calif. L.W. Fleury Jr., Hersey Products Inc., Cranston, R.I. J.W. Furrer, * Hersey Products Inc., Fresno, Calif. G.H. Swenson, G.H. Swenson Enterprises, Clifton Park, N.Y. Dennis Whitelaw, * CMB Industries-Febco, Fresno, Calif. *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 Introduction... vii I.A Background... vii I.B History... vii I.C Acceptance... viii II Special Issues... ix III Use of This Standard... ix III.A Purchaser Options and Alternatives... ix III.B Modification to Standard... ix IV Major Revisions... ix V Comments... ix Standard 1 General 1.1 Scope Purpose Application References Definitions Requirements 4.1 Materials General Design Detailed Design Workmanship Verification 5.1 Testing and Uniformity Delivery 6.1 Marking Preparation for Shipment Affidavit of Compliance Tables 1 Parameters for Reduced-Pressure Principle Backflow Prevention Assembly Pressure Differential Relief Valve Discharge Rates Thermal Test Minimum Flow Rates... 9 v

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7 Foreword This foreword is for information only and is not a part of AWWA C511. I. Introduction. I.A. Background. The production and preservation of safe potable water is the objective of greatest priority for public water utilities and other agencies having jurisdiction. When safe water has been produced and put into the public distribution system, precautions must be taken to be certain that it is not contaminated with water or liquids from other sources. Almost every water-using premises may have actual or potential crossconnection hazards. The water distribution systems of some premises served by public water systems, such as hotels, hospitals, and industrial plants, can be quite complex. On these premises, contaminated backflow into the public system can be a result of either backpressure or backsiphonage from appliances and equipment or from cross-connection with other sources of supply. Cross-connection control programs usually will require that backflow prevention assemblies be installed at the water-service connections to premises where potentially hazardous conditions exist. Water users (utility customers) have a clearly implied responsibility to protect the safety of the water in the public supply system. Water users must also protect the integrity of the water supply on their own premises. Protection of a building s piping system must be done in accordance with the requirements of the local authority having jurisdiction. Cross-connection hazards vary widely in degree. Generally, the degree of protection against backflow resulting from a cross-connection should be commensurate with the degree of hazard. Two types of backflow prevention assemblies are commonly used: the double check valve assembly and the reduced-pressure principle assembly. If local regulations or ordinances do not specify the type to use or the conditions under which one or the other may be used, recommendations may be found in AWWA Manual M14, Recommended Practice for Backflow Prevention and Cross-Connection Control. I.B. History. The Conference of State Sanitary Engineers (CSSE) and the American Water Works Association appointed the Joint Committee on Backflow Preventers and Cross-Connection Control in September 1959 to carry out the recommendations of an earlier joint committee. These recommendations were included in the joint committee s final report published in the December 1958 edition of Journal AWWA. The first chair, Ray L. Derby, then of the Los Angeles Department of Water and Power, served until April From April 1964 until March 1972, Gustave J. Angele Sr., plant sanitary engineer, Union Carbide Nuclear Division, served as chair. From March 1972 until April 1983, Ernest J. Havlina, Los Angeles Department of Water and Power, served as chair. From April 1983 until April 1993, Patrick J. Brady, Department of Public Utilities, County of Henrico, Richmond, Va., served as chair. Since then, the work has been under the direction of the present chair, James T. Cowgill, Hazen & Sawyer Engineers, Hollywood, Fla. The first work of the committee resulted in AWWA Manual M14, which was published in the April 1966 edition of Journal AWWA. After publication of AWWA Manual M14, the committee produced a standard that received final approval from the AWWA Board of Directors on Jan. 27, 1969, and was designated as AWWA C506-69, Standard for Backflow Prevention Devices Reduced vii

8 Pressure Principle and Double Check Valve Types. Revision of AWWA C506 was approved in The 1978 edition was subsequently reaffirmed without revision in In 1989, AWWA C was separated into two standards: AWWA C510 covers the double check valve backflow prevention assembly, and AWWA C511 covers the reduced-pressure principle backflow prevention assembly. This is the second revision to AWWA C511 and was approved by the AWWA Board of Directors on June 15, I.C. Acceptance. In May 1985, the US Environmental Protection Agency (USEPA) entered into a cooperative agreement with a consortium led by NSF International (NSF) to develop voluntary third-party consensus standards and a certification program for all direct and indirect drinking water additives. Other members of the original consortium included the American Water Works Association Research Foundation (AWWARF) and the Conference of State Health and Environmental Managers (COSHEM). The American Water Works Association and the Association of State Drinking Water Administrators (ASDWA) joined later. In the United States, authority to regulate products for use in, or in contact with, drinking water rests with individual states. * Local agencies may choose to impose requirements more stringent than those required by the state. To evaluate the health effects of 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. 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. *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 NSF International, 3475 Plymouth Rd., Ann Arbor, MI Both publications available from National Academy of Sciences, 2102 Constitution Ave. N.W., Washington, DC viii

9 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. II. Special Issues. This standard has no applicable information for this section. III. Use of This Standard. AWWA has no responsibility for the suitability or compatibility of the provisions of this standard to any intended application by any user. Accordingly, each user of this standard is responsible for determining that the standard s provisions are suitable for and compatible with that user s intended application. III.A. Purchaser Options and Alternatives. The following items should be covered in the purchaser s specifications: 1. Standard used that is, AWWA C511, Reduced-Pressure Principle Backflow Prevention Assembly, of latest revision. 2. Whether for hot or cold water (Sec. 1.1). 3. Affidavit of compliance (Sec. 6.3), if required. 4. Certificate of approval (Sec. 6.3), if required. 5. Materials, if other than those specified in Sec Size, flow, and pressure loss (Sec ), and number of assemblies required. 7. Type of end connection flanged, threaded, or grooved and shouldered (Sec ). III.B. Modification to Standard. Any modification to the provisions, definitions, or terminology in this standard must be provided in the purchaser s specifications. IV. Major Revisions. Major revisions made to the standard in this revision include the following: 1. The format has been changed to AWWA standard style. 2. Definitions for cosmetic and structural defect have been added (Sec. 3). 3. A new section on casting requirements has been added (Sec ). 4. The operating temperature range for cold water reduced-pressure principle backflow prevention assemblies has been increased (Sec. 1.1). 5. Table 1, Parameters for Reduced-Pressure Principle Backflow Prevention Assembly, has been expanded to include sizes 1 4 in. (6 mm), 3 8 in. (9 mm), 1 2 in. (12 mm), and 12 in. (305 mm). 6. The section on connections has been expanded to include grooved and shouldered joints (Sec ). 7. The section on test cocks has been expanded to include requirements on test connections (Sec ). 8. Table 2, Pressure Differential Relief Valve Discharge Rates, has been expanded to include sizes 1 4 in. (6 mm), 3 8 in. (9 mm), 1 2 in. (12 mm) and 12 in. (305 mm). 9. A new section on operation at rated temperature and pressure has been added (Sec ). 10. Table 3, Thermal Test Minimum Flow Rates, has been added. V. Comments. If you have any comments or questions about this standard, please call the AWWA Standards and Materials Development Department, (303) ext. 6283, FAX (303) , or write to the department at 6666 W. Quincy Ave., Denver, CO ix

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11 American Water Works Association R ANSI/AWWA C (Revision of ANSI/AWWA C511-92) AWWA STANDARD FOR REDUCED-PRESSURE PRINCIPLE BACKFLOW PREVENTION ASSEMBLY SECTION 1: GENERAL Sec. 1.1 Sec. 1.2 Sec. 1.3 Scope This standard covers the reduced-pressure principle backflow prevention assembly. The assembly shall be capable of withstanding a working water pressure of at least 150 psi (1,034 kpa) without damage to working parts or impairment of function and for operation on hot or cold water lines. This standard covers hot and cold water reduced-pressure principle backflow prevention assemblies. All assemblies shall be designed to, at a minimum, operate at a temperature range of 33 F to 140 F (1 C to 60 C). Hot water assemblies shall be designed to, at a minimum, operate in water at a temperature range of 33 F to 180 F (1 C to 82 C). A complete assembly consists of a mechanical, independently operating, hydraulically dependent relief valve located between two independently operating, internally loaded check valves that are located between two tightly closing resilientseated shutoff valves with four properly placed (see Sec ) resilient-seated test cocks. Purpose The purpose of this standard is to provide the minimum requirements for reduced-pressure principle backflow prevention assemblies, including materials, general and detailed design, workmanship, and shipping and delivery. Application This standard can be referenced in specifications for purchasing and receiving reduced-pressure principle backflow prevention assemblies. The stipulations of this standard apply when this document has been referenced and then only to reducedpressure principle backflow prevention assemblies. 1

12 2 AWWA C SECTION 2: REFERENCES This standard references the following documents. In their latest editions, they form a part of this standard to the extent specified within the standard. In any case of conflict, the requirements of this standard shall prevail. ANSI * /ASME B Pipe Threads, General Purpose (Inch). ANSI/ASME B16.1 Cast Iron Pipe Flanges and Flanged Fittings, Class 25, 125, and 250. ANSI/ASME B16.24 Standard for Cast Copper Alloy Pipe Flanges and Flanged Fittings Class 150, 300, 400, 600, 900, 1500, and 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 C509 Standard for Resilient-Seated Gate Valves for Water Supply Service. ANSI/AWWA C550 Standard for Protective Epoxy Interior Coatings for Valves and Hydrants. ANSI/AWWA C606 Standard for Grooved and Shouldered Joints. 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 A276 Standard Specification for Stainless Steel Bars and Shapes. ASTM A313/A313M Standard Specification for Stainless Steel Spring Wire. 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 B61 Standard Specification for Steam or Valve Bronze Castings. ASTM B62 Standard Specification for Composition Bronze or Ounce Metal Castings. ASTM B139 Standard Specification for Phosphor Bronze Rod, Bar, and Shapes. ASTM B159 Standard Specification for Phosphor Bronze Wire. ASTM B584 Standard Specification for Copper Alloy Sand Castings for General Applications. ASTM D2240 Test Method for Rubber Property Durometer Hardness. AWWA M14 Recommended Practice for Backflow Prevention and Cross- Connection Control, Denver (1990). *American National Standards Institute, 11 W. 42nd St., New York, NY American Society of Mechanical Engineers, 345 E. 47th St., New York, NY American Society for Testing and Materials, 100 Barr Harbor Dr., West Conshohocken, PA

13 REDUCED-PRESSURE PRINCIPLE ASSEMBLY 3 Food and Drug Administration Document, * Title 21 of the Code of Federal Regulations on Food Additives, Sec SAE J513 Refrigeration Tube Fittings General Specifications, Standard. SECTION 3: DEFINITIONS The following definitions shall apply in this standard: 1. 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. 2. Full-ported test cock: A full-ported test cock shall have an opening at least equal in area to the area of the specified size of the test cock. 3. Independently acting check valve: An independent check valve shall share no common parts except for body housing. There can be no contact between any moving components of either check valve through its normal operation. The failure of either check valve in any mode can in no way affect the operation of the other check valve. 4. Manufacturer: The party that manufactures, fabricates, or produces materials or products. 5. Purchaser: The person, company, or organization that purchases any materials or work to be performed. 6. 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. 7. Supplier: The party that supplies material or services. A supplier may or may not be the manufacturer. SECTION 4: REQUIREMENTS Sec. 4.1 Materials Dissimilar metals. In the presence of an electrolyte, direct contact between metals of dissimilar corrosion resistance may result in galvanic corrosion of the more active, less corrosion-resistant material. When dissimilar metals must be used for internal parts, the rate of corrosion shall be reduced as much as practical through the selection of materials that exhibit similar resistance to corrosion, or by placing a dielectric material between the metals, or by applying a dielectric coating. When contact between dissimilar metals cannot be avoided, the assembly shall be *Available from the US Government Printing Office, Superintendent of Documents, Washington, DC Society of Automotive Engineers, 400 Commonwealth Dr., Warrendale, PA

14 4 AWWA C designed so that the resulting corrosion will be minimized and will not adversely affect water quality or result in malfunctioning or premature failure of the assembly Protective coatings. All ferrous bodies and parts shall be coated with a polymerized coating or shall be hot-dip galvanized in conformance with ASTM A153. The use of synthetic coatings on ferrous bodies and parts shall be subject to approval by the purchaser. This approval applies not only to the specific use, but also to the coating and application process. The protective coating shall be composed of materials referenced in ANSI/ AWWA C550 as deemed acceptable in the Food and Drug Administration (FDA) Document, Title 21, of the Code of Federal Regulations on Food Additives, Sec The manufacturer shall provide documentation verifying compliance with this document when requested Material requirements. The following material specifications shall apply: 1. Valve bodies and covers, spools, and spacers bronze (ASTM B61, ASTM B62, or ASTM B584 C84400). 2. Valve bodies and covers, spools, and spacers gray iron (ASTM A126, Class B) or ductile iron (ASTM A395 or ASTM A536). 3. Clapper and poppet facing rings molded synthetic rubber (Shore Durometer hardness A scale [ASTM D2240]). 4. Relief valve facing rings molded synthetic rubber (Shore Durometer hardness A scale). 5. Swing pin and guide stem phosphor bronze (ASTM B139, UNS numbers C51000, C52100, or C52400). 6. Swing pin and guide stem stainless steel (ASTM A276, UNS numbers S30400, S30500, or S31600). 7. Springs stainless steel (ASTM A313). 8. Springs phosphor bronze (ASTM B159). 9. Diaphragms synthetic rubber or thermoplastic elastomer with cotton or rayon cloth insert. 10. Seat rings or valve seats bronze (ASTM B61) or stainless steel (ASTM A276, UNS numbers S30400, S30500, or S31600). Other alloys, rubbers, plastics, or other materials that are adaptable and will give at least equivalent trouble-free service may be used if tested and found equivalent. Sec. 4.2 General Design Size, rated flow, and allowable pressure loss Nominal size. The size of a backflow prevention assembly as indicated in Table 1 shall be identified by the size of the resilient-seated shutoff valves provided as part of the assembly and attached at each end of the assembly Rated flow and allowable pressure loss. The maximum allowable pressure loss at any rate of flow, from zero and up to and including the maximum rated flow for the indicated size, shall not exceed the values shown in Table General flow and operating requirements. The water passageways shall be streamlined to minimize turbulence and pressure loss. Moving parts shall be designed to operate in a positive manner, without chatter. Differential pressure relief valves shall open and close positively and quietly and shall not hunt excessively under normal fluctuations of flow rate or pressure. The design of the assembly shall be such that it will not cause undue pressure surges during a cycle of operation, and the operation of the assembly shall not be impaired by the water-pressure surges that

15 REDUCED-PRESSURE PRINCIPLE ASSEMBLY 5 Table 1 Parameters for reduced-pressure principle backflow prevention assembly Nominal Size Maximum Rated Flow Maximum Allowable Pressure Loss in. (mm *) gpm (L/s) psi (kpa) 1 4 (6) 1 (0.06) 24 (165.4) 3 8 (9) 3 (0.19) 22 (151.6) 1 2 (12) 7.5 (0.47) 22 (151.6) 3 4 (19) 30 (1.89) 20 (137.88) 1 (25) 50 (3.15) 18 (124.09) (31) 75 (4.73) 18 (124.09) (38) 100 (6.31) 16 (110.30) 2 (50) 160 (10.10) 16 (110.30) (64) 225 (14.20) 16 (110.30) 3 (75) 320 (20.19) 15 (103.41) 4 (100) 500 (31.55) 14 (96.51) 6 (150) 1,000 (63.10) 14 (96.51) 8 (200) 1,600 (100.96) 14 (96.51) 10 (250) 2,300 (145.13) 14 (96.51) 12 (305) 3,000 (189.30) 14 (96.51) *Metric conversions given in this standard are direct conversions of US customary units and are not those specified in International Organization for Standardization (ISO) standards. are normally encountered in a water supply system. The assembly shall be sensitive enough to react to pressure conditions without a time lag that would allow backflow Structural and operational capability Structural capability. The casing of the assembly, with all covers bolted in place, shall be capable of withstanding an internal hydrostatic test pressure of at least twice the maximum working water pressure of the assembly for at least 10 min without leaking, weeping, or dripping through any part of the casing, or casings, or at any joint or connection. All barriers to flow, including check valves, diaphragms, and bellows, shall be capable of withstanding, without damage or permanent deformation for at least 10 min without leaking, a hydrostatic test pressure of at least twice the maximum working water pressure of the assembly against the closed side of the barrier simultaneous with atmospheric pressure on the other side. The backpressure test on the first check valve must be performed with the relief valve mechanically held closed Operational capability. The assembly shall be capable of going through a full cycle of operation, during which the operating pressure on the inlet side of the assembly drops sharply from 150 psi (1,034 kpa) to atmospheric and returns slowly after a short time interval to 150 psi (1,034 kpa) without permanent distortion or damage to any of its parts. Sec. 4.3 Detailed Design Design of assembly. It is essential that all assemblies be trouble-free; that moving parts do not bind or gall; and that there be no distortion that will

16 6 AWWA C interfere with the intended performance of the assembly. Flow channels shall be streamlined to prevent cavitation, minimize pressure loss, and eliminate pockets that could entrap foreign materials Access to internal parts. All internal parts shall be accessible for inspection, repair, and renewal without removing the assembly from the line using the shutoff valves to isolate the backflow preventer Area of waterways. The assembly shall be designed so that the minimum waterway area normal to the direction of flow shall not adversely affect the overall pressure loss Clearance of moving parts. Clearance between valve stems and associated guides, hinge pins and bushings, and other similar parts shall be designed to yield a low probability of malfunctioning due to corrosion or deposit of foreign matter on surfaces of the assembly. Minimum clearance between the body of the check valve and hinge arm, clapper, counterweight, poppet valve, or other free-moving part shall be as follows: 1. Iron-body parts of all sizes: 1 2 in. (12 mm). 2. Brass or bronze parts up to and including 1-in. (25-mm) size: 1 8 in. (3 mm). 3. Brass or bronze parts greater than 1-in. (25-mm) size: 1 4 in. (6 mm) Facing rings for poppet-type valves. For all sizes of poppet valves, the elastomer disc shall be supported by an adequate bearing surface, such that the elastomer disc will comply with all tests contained in this document. The facing ring shall overhang the outside edge of the seat ring by at least 1 16 in. (1.6 mm). There shall be a minimum of 1 16 in. (1.6 mm) between the inside edge of the seat ring and the facing ring clamp when used Facing rings for swing-type valves. The elastomer disc shall be supported by an adequate bearing surface, such that the elastomer disc will comply with all tests contained in this document. In sizes up to 2 in. (50 mm), the facing ring shall overhang the outer edge of the sealing surface of the seat ring by at least 1 8 in. (3 mm). In sizes of 2 in. (50 mm) and larger, the overhang shall be at least 1 4 in. (6 mm). There shall be a minimum of 1 16 in. (1.6 mm) between the inside edge of the seat ring and the facing ring clamp when used Bushings. All bushings shall project at least 1 4 in. (6 mm) inside the body of the component involved Connections. End connections, test cocks, and control piping connections to components of the backflow prevention assembly shall be either threaded, in accordance with ANSI/ASME B1.20.1, or flanged, in accordance with ANSI/ASME B16.1, ANSI/ASME B16.24, or ANSI/AWWA C110/A21.10, or grooved and shouldered joints per ANSI/AWWA C Test cocks. Resilient-seated, full-ported test cocks shall be attached to corrosion-resistant nipples or have male threads to be installed in tapped holes. At each location on a valve body where such a tapped hole is required, there shall be a boss to permit sufficient threading for nipples. Test cocks shall have female iron pipe size (IPS) ends on the discharge side. Test connections of 1 8 in. (3 mm) shall be permitted to be either IPS female threads or male 1 4 in. (6 mm) flared-type connections per SAE J513. The minimum sizes (IPS) of test cocks shall be 1 8 in. (3 mm) for assemblies up to and including 1-in. (25-mm) nominal size; 1 4 in. (6 mm) for assemblies up to and including 2-in. (50-mm) nominal size; 1 2 in. (12 mm) for assemblies in. through 4-in. (64-mm through 100-mm) nominal size; and 3 4 in.

17 REDUCED-PRESSURE PRINCIPLE ASSEMBLY 7 (19 mm) for assemblies 6 in. (150 mm) and larger. Test cocks shall be installed at the following locations on all backflow prevention assemblies: 1. On the supply (inlet) side of the supply shutoff valve. 2. Between the supply shutoff valve and the first check valve. 3. Between the check valves. 4. Between the second check valve and the shutoff valve on the outlet side of the assembly Control piping. Control piping and passageways shall be of corrosionresistant material. They shall be large enough to prevent clogging and shall not be located in such a way as to cause entrapment of foreign materials. External control piping shall be located close to the body of the assembly and shall be as short as possible to reduce accidental or malicious damage to the unit Diaphragms. Diaphragms or bellows that are designed to serve as barriers in control piping that bypasses one or more check valves in the backflow prevention assembly shall be installed in such a way that a failure of the diaphragm or bellows will result in visible evidence of the failure Air release. Provision shall be made for bleeding trapped air from the components of the assembly Valve seats. Provision shall be made for renewal and replacement of valve seats in iron-body components Alignment of check valves. Each clapper disc, facing ring, and clamping and securing bolt or stud shall be concentric to an axis that is normal to the face of the facing ring. When applicable, the unit shall be designed so that the facing ring may be clamped and reclamped without warping its face. The clapper must not be able to tip and catch under the seat ring. When clappers or poppets are in a wideopen position, they must bear on a definite stop that is so designed and placed that the action of the water will not twist or bend the valve parts or cause them to chatter. The design shall be such that at all flow rates, from zero to (and including) rated flow, the component parts shall not create any chatter or noise. All working parts shall be designed and supported in a manner to preclude distortion or misalignment Shutoff valves. Resilient-seated shutoff valves shall be considered an integral part of the assembly. For the 3-in. (75-mm) and larger assemblies, the resilient-seated gate valves shall conform to ANSI/AWWA C509. The in. (64-mm) gate valves are to be constructed according to the applicable requirements of ANSI/ AWWA C509, even though they are not specifically listed in the standard. Shutoff valves smaller than in. (64-mm) size shall be resilient seated and of a quality acceptable to the purchaser. Ferrous metal surfaces shall be coated with a polymerized coating in accordance with ANSI/AWWA C Operating requirements for reduced-pressure principle backflow prevention assembly Normal conditions. During normal operating conditions, whether or not there is flow through the assembly, the pressure in the zone between the check valves shall be at least 2 psi (13.8 kpa) less than the pressure on the supply (inlet) side of the assembly No flow from the supply side. When there is no flow from the supply side of the assembly and the supply pressure drops to 2 psi (l3.8 kpa), the pressure within the zone shall be atmospheric. As the supply pressure drops below 2 psi (13.8 kpa), the relief valve shall continue to open and shall reach and maintain the fully open position as the supply pressure drops to atmospheric or lower.

18 8 AWWA C Table 2 Pressure differential relief valve discharge rates Nominal Size of Assembly Relief Valve Discharge Rate * in. (mm) gpm (L/s) 1 4 (6) 0.5 (0.03) 3 8 (9) 1 (0.06) 1 2 (12) 3 (0.19) 3 4 (19) 5 (0.32) 1 (25) 5 (0.32) (31) 10 (0.63) (38) 10 (0.63) 2 (50) 20 (1.26) (64) 20 (1.26) 3 (75) 30 (1.89) 4 (100) 40 (2.52) 6 (150) 40 (2.52) 8 (200) 60 (3.78) 10 (250) 60 (3.78) 12 (305) 75 (4.73) *These are minimum discharge rates at which the capability of the relief valve to maintain zone pressure specified in Sec , paragraphs and , are measured Downstream pressure approaches within 0.5 psi (3.44 kpa) of supply pressure. When the downstream pressure approaches within 0.5 psi (3.44 kpa) of the supply pressure, with the checking member of the second check valve physically removed and the supply pressure at least equal to the rated water working pressure of the assembly, the relief valve shall discharge water from the zone to the atmosphere with the rate of discharge corresponding to the data shown in Table Downstream pressure exceeds the supply pressure of 0 psi. When the downstream pressure exceeds the supply pressure, with a fouled check valve 2, and the supply pressure is at atmospheric, the relief valve shall discharge water from the zone to the atmosphere with the rate of discharge corresponding to the data shown in Table 2, and the pressure in the zone shall not exceed 1.5 psi (10.34 kpa) Outlet check valve pressure. The outlet check valve shall be internally loaded so that when the pressure on the inlet side of the valve is at least 1 psi (6.89 kpa) and the outlet pressure is atmospheric, the valve will be drip-tight in the normal direction of flow Inlet check valve pressure. To prevent excessive discharge due to pressure fluctuation, the minimum pressure differential across the first check valve under normal conditions shall be at least 3 psi (20.7 kpa) greater than the pressure differential necessary to cause the relief valve to open Discharge port. The discharge port of the relief valve shall be of such design as to restrict the attachment of a hose, pipe, or plate Installation instructions. The manufacturer shall include with each unit installation instructions, attached to the unit, to designate that the relief valve and relief valve discharge port shall be low enough to drain the intermediate zone

19 REDUCED-PRESSURE PRINCIPLE ASSEMBLY 9 Table 3 Thermal test minimum flow rates Size of Assembly Minimum Flow Rate in. (mm) gpm (L/s) 1 4 (6) 1 (0.06) 3 8 (9) 3 (0.19) 1 2 (12) 7.5 (0.47) (19 25) 30 (1.89) (31 50) 40 (2.52) (64 305) 50 (3.15) chamber of the reduced-pressure principle assembly to the lowest point of the first check valve. The differential pressure relief valve shall be located so that the relief valve seat and discharge port are below the lowest portion of check valve 1 to prevent backsiphonage Operation at rated temperature and pressure. All components of the assembly shall operate at, and withstand a thermal test at the greater of 140 F (60 C) or at the maximum working water temperature (MWWT), maximum working water pressure (MWWP), and the flow rate as specified in Table 3, for a minimum period of 100 hours without any leakage, damage, permanent deformation, or impairment of operation. During and after a minimum of 100 hours at rated temperature and pressure the assembly shall operate satisfactorily per Sec , , and Sec. 4.4 Workmanship Foundry and machine work. All foundry and machine work shall be performed in accordance with the best modern practice for the class of work involved. All parts shall conform, within allowable tolerances, to the manufacturer s specifications and shall be free from defects Joints. All flanged joints shall be faced true and machined at right angles to their respective axes; threaded joints must be concentric and accurately cut Bronze mounting. All ferrous parts receiving a bronze mounting shall be finished to fit. Such handwork as is required in finishing shall produce a neat, professional, well-fitting, and smoothly operating product 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.

20 10 AWWA C SECTION 5: VERIFICATION Sec. 5.1 Testing and Uniformity All joints shall be watertight when subjected to water pressure at twice the maximum working water pressure. All assembly parts of the same size, model, and manufacture shall be interchangeable. SECTION 6: DELIVERY * Sec. 6.1 Sec. 6.2 Sec. 6.3 Marking Backflow prevention assemblies shall be marked distinctly with the size, model designation, and serial number. The markings, which shall not be easily defaced, shall be either cast or stamped in the metal or stamped on a brass or stainless-steel nameplate permanently affixed to the assembly. Serial numbers, size, and model shall be at least 3 16 in. (5 mm) in height. The markings shall include the following: 1. Name of manufacturer or trademark. 2. Type: reduced-pressure principle assembly or RP. 3. Size. 4. Model designation. 5. Direction of flow (indicated by an arrow). 6. Serial number. 7. Maximum working water pressure (MWWP). 8. Maximum working water temperature (MWWT) (in degrees Fahrenheit or Celsius). Preparation for Shipment Backflow prevention assemblies shall be complete when shipped. The manufacturer shall use due and customary care in preparing the assemblies for shipment so that no damage as a result of the manufacturer s negligence occurs in handling or in transit. The backflow prevention assemblies shall be drained completely and all openings closed completely before shipment. Affidavit of Compliance If required by the purchaser s specifications, the supplier shall furnish an affidavit certifying that the assemblies furnished comply with all applicable requirements of this standard. If required by the purchaser s specifications, the supplier shall furnish a certificate of approval from a laboratory recognized as having expertise in this specialized field Requirements for approval. Each backflow prevention assembly approved by the testing laboratory shall satisfactorily pass a laboratory evaluation and field evaluation in accordance with the requirements of this section. * Governmental marking, packaging, and shipping reference reflect US requirements. Users of AWWA C511 in Canada, Mexico, and non-north American countries should verify applicable local and national regulatory requirements.

21 REDUCED-PRESSURE PRINCIPLE ASSEMBLY Evaluation in the laboratory. One or more units, selected at random by the testing laboratory from the manufacturer s stock, shall be thoroughly evaluated by the testing laboratory as to the unit s design and operating characteristics up to the assemblies rated temperature and pressure. This evaluation shall include a review of the working drawings and manufacturer s specifications for all parts and materials used, hydrostatic testing, and any other evaluation needed to ensure compliance with this standard Evaluation in the field. On completion of a satisfactory laboratory evaluation, three units of each size and model, selected at random by the testing laboratory from the manufacturer s stock, shall satisfactorily pass a 12-consecutivemonth field evaluation under the supervision of the testing laboratory. Certification by a state health department, a provincial authority, or the regulatory authority having jurisdiction with an equivalent field test program shall be acceptable as evidence of satisfactory field-test evaluation Selection of field locations. Field locations shall be selected or approved by the testing laboratory, or the authority having jurisdiction, or both Field testing. All three units of each size and model of assembly undergoing field evaluation shall be examined and tested at least monthly according to the operation requirements of this standard. Records of the field examinations and tests shall be kept and all problems and malfunctions noted. Any design or operational problems that prevent the assemblies from meeting the requirements of this standard shall be cause for rejection Evaluation report. At the conclusion of the testing program for each size and model of assembly, a report shall be compiled by the testing laboratory or authority, or both, indicating the tests that are performed to ascertain compliance with each section to this standard. The report shall describe all problems and malfunctions. On satisfactory completion of the evaluation, a certificate of approval shall be issued.

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