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Approved devices to protect against backflow or back siphonage shall be installed at all fixtures and equipment where backflow and/or back siphonage may occur and where there is a hazard to the potable water supply, in that polluted water or other contaminated materials may enter into the public water supply. Any situation in which a heavy withdrawal of water, such as a sudden break in the main or water being used from a fire hydrant, may cause a negative pressure to develop which could lead to back siphonage of polluted water into the system shall be improper and must be protected by approved backflow preventive valves and systems as determined by the Superintendent of Public Works. (Ord. 936, 1-7-1991; amd. 1998 Code)
The minimum air gap to afford backflow protection shall be in accordance with the following chart:
A. Atmospheric Vacuum Breaker (AVB): An atmospheric vacuum breaker consists of a body, a checking member and an atmospheric opening.
B. Double Check Valve Backflow Prevention Assembly (DC): A double check valve backflow prevention assembly consists of two (2) independently acting internally loaded check valves, four (4) properly located test cocks and two (2) isolation valves.
C. Pressure Vacuum Breaker Backflow Prevention Assembly (PVB): A pressure vacuum breaker backflow prevention assembly consists of a loaded air inlet valve, an internally loaded check valve, two (2) properly located test cocks and two (2) isolation valves.
D. Reduced Pressure Principle Backflow Prevention Assembly (RP): A reduced pressure principle backflow prevention assembly consists of two (2) independently acting internally loaded check valves, a differential pressure relief valve, four (4) properly located test cocks and two (2) isolation valves. (Ord. 938, 6-3-1991)
A. Conform To Standards: All assemblies shall conform to listed standards and be acceptable to the Superintendent of Public Works having jurisdiction over the selection and installation of backflow prevention assemblies.
B. Testing: The premises owner or responsible person shall have the backflow prevention assembly tested by a certified backflow tester at the time of installation, repair or relocation and at least on an annual schedule thereafter or more often when required by the Superintendent of Public Works.
C. Access And Clearance: Access and clearance shall be provided for the required testing, maintenance and repair. Access and clearance shall require a minimum of one foot (1') (305 mm) between the lowest portion of the assembly and grade, floor or platform. Installations elevated more than five feet (5') (1.52 m) above the floor or grade shall be provided with a permanent platform capable of supporting a tester or maintenance person. (See Appendix A at Section 8-3-8 of this Chapter.)
D. Direct Connections: Direct connections between potable water piping and sewer connected wastes shall not exist under any condition with or without backflow protection. Where potable water is discharged to the drainage system, it shall be by means of an approved air gap of two (2) pipe diameters of the supply inlet, but in no case shall the gap be less than one inch (1") (25 mm). Connection may be made to the inlet side of a trap; provided, that an approved atmospheric vacuum breaker is installed not less than six inches (6") (152.4 mm) above the flood level rim of such trapped fixture, so that at no time will any such device be subjected to any back pressure.
E. Hot Water: Backflow preventers for hot water over one hundred ten degrees Fahrenheit (110°F) (43.3 degrees C) shall be a listed type designated to operate at temperatures of one hundred ten degrees Fahrenheit (110°F) (43.3 degrees C) or more without rendering any portion of the assembly inoperative.
F. Integrated Preventers: Fixtures, appliances or appurtenances with integral backflow preventers or integral air gaps manufactured as a unit shall be installed in accordance with their listing requirements.
G. Cold Climates: In cold climate areas, backflow assemblies and devices shall be protected from freezing by a method acceptable to the Superintendent of Public Works. (Ord. 938, 6-3-1991; amd. 1998 Code)
A. Vacuum Breaker: Water closet and urinal flushometer valves shall be equipped with a listed atmospheric vacuum breaker. The vacuum breaker shall be installed on the discharge side of the flushometer valve with the critical level at least six inches (6") (152.4 mm) or the distance according to its listing above the overflow rim of a water closet bowl or the highest part of a urinal. (Ord. 938, 6-3-1991; amd. 1998 Code)
B. Ballcock: Water closet and urinal tanks shall be equipped with a listing ballcock. The ballcock shall be installed with the critical level at least one inch (1") (25 mm) above the full opening of the overflow pipe. In cases where the ballcock has no hush tube, the bottom of the water supply inlet shall be installed one inch (1") (25 mm) above the full opening of the overflow pipe. Water closets having the flush valve seat less than one inch (1") (25 mm) above the flood level rim of the closet bowl shall have the ballcock installed in a separate and isolated compartment of the tank, or shall be provided with a sheathed ballcock, or other equivalent protection.
C. Water Closet Flushometer Tanks: Water closet flushometer tanks shall be protected against backflow by an approved backflow prevention assembly, device or method.
D. Heat Exchangers: Heat exchangers and other assemblies or methods of construction using potable water shall be of listed construction and materials. Potable water shall be separated from the fluids or gasses by a minimum of two (2) separate walls, with a positive, vented leak detection path. The sections in contact with potable water shall be of material and weights suitable for potable water as set forth in this Chapter.
E. Inlets To Tanks, Vats, Sumps, Swimming Pools: Inlets to tanks, vats, sumps, swimming pools and other receptors when protected by a listed atmospheric vacuum breaker shall have such atmospheric breaker installed on the discharge side of the last valve with the critical level not less than six inches (6") (152.4 mm) or in accordance with its listing above the flood level rim of such equipment, and all downstream piping. Water supply inlets not protected by atmospheric vacuum breakers shall be protected by an approved air gap. Where atmospheric vacuum breakers or air gaps are not installed, other backflow preventers suitable for the possible contamination or pollution may be installed in accordance with the requirements for that type of device or assembly as set forth in this Chapter.
F. Lawn Sprinkling Systems: Lawn sprinkling systems shall be equipped with listed atmospheric vacuum breakers installed on the discharge side of each of the last shutoff valves. Where atmospheric vacuum breakers cannot be installed because of piping elevation or valves, other listed backflow preventers shall be installed in accordance with their requirements as set forth in this Chapter.
G. Potable Water Outlets: Potable water outlets with hose attachments other than water heater drains and clothes washer connections shall be protected by a listed nonremovable hose bib-type backflow preventer or by a listed atmospheric vacuum breaker installed at least six inches (6") (152.4 mm) above the highest point of usage and located on the discharge side of the last valve. In climates where freezing temperatures occur, a listed self-draining frost-proof hose bib with an integral backflow preventer shall be used.
H. Water Cooled Equipment: Water cooled compressors, degreasers or any other water cooled equipment shall be protected by a listed backflow preventer installed in accordance with the requirements of this Chapter.
Note: Some water cooled equipment may produce back pressure and shall be equipped with the appropriate protection. (Ord. 938, 6-3-1991)
I. Water Inlets To Water Supplied Aspirators: Water inlets to water supplied aspirators shall be equipped with a listed atmospheric vacuum breaker mounted at least six inches (6") (152.4 mm) above the aspirator unit or equipped with a listed backflow preventer installed in accordance with its listing requirements and this Chapter. The discharge shall drain through an air gap. When using the tail piece of a fixture to receive the discharge of an aspirator, the air gap shall be located above the flood level rim of the fixture.
J. Potable Water Makeup Connections: Potable water makeup connections to steam or hot water boilers shall be provided with a listed backflow protection assembly.
K. Nonpotable Water Piping: In cases where it is impractical to correct individual cross-connections on the domestic water line, the line supplying such outlets shall be considered a nonpotable water line. No drinking or domestic water outlets shall be connected to the nonpotable water line. Whenever possible, all portions of the nonpotable water line shall be exposed and all exposed portions shall be properly identified in a manner satisfactory to the Superintendent of Public Works. Each outlet on the nonpotable water line which may be used for drinking or domestic purposes shall be posted: "Danger - Unsafe Water".
L. Potable Water Supply To Carbonators: Potable water supply to carbonators shall be protected by backflow protection as approved by the Superintendent of Public Works and installed per the requirements of this Chapter.
M. Location Of Backflow Preventers: Backflow preventers shall not be located in any area containing fumes that are toxic, poisonous or corrosive. (Ord. 938, 6-3-1991; amd. 1998 Code)
The Superintendent of Public Works or other designee of the City Council shall have the right of entry into any building or premises in the City as frequently as necessary in his or her judgment in order to ensure that plumbing has been installed in accordance with the laws of the City so as to prevent the possibility of pollution of the water supply of the City. (Ord. 936, 1-7-1991; amd. 1998 Code)
Pursuant to the City's constitutional home rule authority and Kansas Statutes Annotated section 65-163a, the City, by its Superintendent of Public Works, may refuse to deliver water through pipes and mains to any premises where a condition exists which might lead to the contamination of the public water system and it may continue to refuse the delivery of water to the premises until that condition is remedied. In addition, the Superintendent of Public Works may terminate water service to any property where the cross-connections or back siphonage condition creates, in the judgment of the Superintendent of Public Works, an emergency danger of contamination to the public water supply. (Ord. 936, 1-7-1991; amd. 1998 Code)
Backflow Assemblies, Devices And Methods | |||||
Degree Of Hazard | |||||
Device, Assembly Or Method1 | Pollution (Low Hazard) | Contamination (High Hazard) | Installation2, 3 | ||
Back Siphonage | Back Pressure | Back Siphonage | Back Pressure | ||
Backflow Assemblies, Devices And Methods | |||||
Degree Of Hazard | |||||
Device, Assembly Or Method1 | Pollution (Low Hazard) | Contamination (High Hazard) | Installation2, 3 | ||
Back Siphonage | Back Pressure | Back Siphonage | Back Pressure | ||
Air gap | X | X | See table in this Chapter. | ||
Atmospheric vacuum breaker | X | X | Upright position. No valves downstream. Minimum of 6" or listed distance above all downstream piping and flood level rim of receptor4. | ||
Double check valve backflow preventer | X | X | Horizontal, unless otherwise listed. Requires 1' minimum clearance at bottom for maintenance. May need platform/ladder for test and repair. Does not discharge water. | ||
Pressure vacuum breaker | X | X | Upright position. May have valves downstream. Minimum of 12" above all downstream piping and flood level rim of receptor. May discharge water. | ||
Reduced pressure principle backflow preventer | X | X | X | X | Horizontal unless otherwise listed. Requires 1' minimum clearance at bottom for maintenance. May need platform/ladder for test and repair. May discharge water. |
1 See description of devices and assemblies in this Chapter. 2 Installation in pit or vault requires previous approval by the Superintendent of Public Works. 3 Refer to general and specific requirements for installation. 4 Not to be subjected to operating pressure for more than 12 hours in any 24-hour period. | |||||
Minimum Air Gaps For Water Distribution4 | ||
Fixtures | When not affected by side walls1 Inches (mm) | When affected by side walls2 Inches (mm) |
Lavatories and other fixtures with effective openings3 not greater than 1/2" (13 mm) in diameter | 1" (25 mm) | 11/2" (38 mm) |
Sinks, laundry trays, goose neck bath faucets and other fixtures with effective openings3 not greater than 3/4" (19 mm) in diameter | 11/2" (38 mm) | 21/4" (57 mm) |
Over rim bath fillers and other fixtures with effective openings3 not greater than 1" (25 mm) in diameter | 2" (51 mm) | 3" (76 mm) |
Effective openings3 greater than 1" (25 mm) in diameter | 2 times diameter of effective opening | 3 times diameter of effective opening |
1 Side walls, ribs or similar obstructions do not affect air gaps when spaced from the inside edge of the spout opening a distance greater than 3 times the diameter of the effective opening for a single wall or a distance greater than 4 times the effective opening for 2 intersecting walls. 2 Vertical walls, ribs or similar obstructions extending from the water surface to or above the horizontal plane of the spout opening other than specified in Note 1 above. The effect of 3 or more such vertical walls or ribs has not been determined. In such cases, the air gap shall be measured from the top of the wall. 3 The effective opening shall be the minimum cross-sectional area at the seat of the control valve or the supply pipe or tubing which feeds the device or outlet. If 2 or more lines supply one outlet, the effective opening shall be the sum of the cross-sectional areas of the individual supply lines or the area of the single outlet, whichever is smaller. 4 Air gaps less than 1" (25 mm) shall only be approved as a permanent part of a listed assembly that has been tested under actual backflow conditions with vacuums of from 1 to 25" of mercury. | ||
(Ord. 938, 6-3-1991; amd. 1998 Code)