(a) Generally.
(1) Approved devices. Approved devices shall be installed at all fixtures and equipment where backflow or backsiphonage may occur and where a minimum air gap between the potable water outlet and the fixture or equipment flood-level rim cannot be maintained.
(2) Backflow, back pressure, and backsiphonage devices.
(A) Generally. Backflow and backsiphonage devices of all types shall be in an accessible location. Installation in pits or any other location not properly drained shall be prohibited, except that dual check valves my be installed in the meter box.
(B) Connections not subject to backpressure. Where a water connection is not subject to back pressure, a vacuum breaker shall be installed on the discharge side of the last valve on the line serving the fixture or equipment. A list of some conditions requiring protective devices of this kind are given in the following table titled cross-connections where protective devices are required.
Cross-Connections Where Protective Devices Are Required and Critical Level (C-L Settings for Vacuum Breakers
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Fixtures or Equipment | Method of Installation |
Cross-Connections Where Protective Devices Are Required and Critical Level (C-L Settings for Vacuum Breakers
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Fixtures or Equipment | Method of Installation |
Aspirators and ejectors | C-L at least 6 inches above flood level of receptacle served |
Commercial dish washing machine | C-L at least 6 inches above flood level of machine. Installed on both hot and cold water supply lines |
Commercial laundry machines | C-L at least 6 inches above flood level of machine. Installed on both hot and cold water supply lines |
Dental units | On models without built in vacuum breakers C-L at least 6 inches above flood level rim of bowl |
Flush tanks | Equipment with approved ball cock, installed according to manufacturer’s instructions |
Garbage can cleaning machines | C-L at least 6 inches above flood level of machine. Installed on both hot and cold water supply lines |
Hose bibs | C-L at least 6 inches above flood level of receptacle served |
Hose outlets | C-L at least 6 inches above highest point on hose line |
Lawn sprinklers | C-L at least 6 inches above highest sprinkler head or discharge outlet |
Steam tables | C-L at least 6 inches above flood level rim |
Tanks and vats | C-L at least 6 inches above flood level rim or line |
Through urinals | C-L at least 30 inches above perforated flush pipe |
(b) Connections subject to backpressure. Where a potable water connection is made to a line, fixture, tank, vat, pump or other equipment with a hazard of backflow or backsiphonage where the water connection is subject to backpressure and an air gap cannot be installed, the City Administrator may require the use of an approved reduced pressure principle backflow preventer. A partial list of such connections is shown in the following table “Partial List of Cross-Connections Subject to Back Pressure”.
Partial List of Cross-Connections Subject to Back Pressure
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Chemical lines | Pumps |
Dock water outlets | Steam lines |
Individual water supplies | Swimming pools |
Industrial process water lines | Pressure tanks |
Tanks & vats - bottom inlets | Horse bibs |
(c) Barometric loop. Water connections, where an actual or potential backsiphonage hazard exists, may, in lieu of devices specified above, be provided with a barometric loop. Barometric loops shall precede the point of connection.
(d) Dual check valve. Dual check valves may be installed at the meter. These valves shall be inspected and repaired not less frequent than every third year. These valves shall be installed only in situations where the City Administrator is assured that only non contaminating substances are subject to backflow into the potable system.
(e) Vacuum breakers. Atmospheric vacuum breakers shall be installed with the critical level at least six inches above the flood rim of the fixture they serve and on the discharge side of the last control valve to the fixture. No shut-off valve or faucet shall be installed beyond the atmospheric vacuum breaker. Pressure vacuum breakers shall be installed with the critical level at least 12 inches above the flood rim, but may have control valves down stream from the vacuum breaker. For closed equipment or vessels, such as pressure sterilizers, the top of the vessel shall be considered the flood level rim and a check valve shall be installed on the discharge side of the pressure vacuum breaker.
(Ord. 768, passed 8-21-1989)