Unless the context requires otherwise, for purposes of this chapter the following mean:
"Air gap separation"means the physical vertical separation between the free flowing discharge end of a potable water supply pipe line and the open or non-pressure-receiving vessel. The separation must be at least twice the inside diameter of the supply line, but never less than one inch.
Approved Backflow Prevention Assembly.Assemblies and devices shall be approved by the University of Southern California, Foundation for Cross Connection Control and Hydraulic Research, or other Oregon Health Authority approved and equivalent testing laboratories.
"Backflow"means the flow of water or other liquids, gases, or other substances into the distributing piping of the public potable water supply.
"Backflow assembly tester"means a person who is certified by the Oregon Health Authority to test approved backflow prevention assemblies.
"Backflow prevention assembly"means assembly used to prevent backflow into a potable water system. Approved assemblies will have attached resilient seat shut-off valves on the inlet and outlet ends of the assembly and the appropriate connections for testing. The types of assembly used include:
a. Double check valve assembly (DCVA);
b. Pressure vacuum breaker assembly (PVBA); protects against backsiphonage only;
c. Reduced pressure backflow assembly (RPBA);
e. Reduced pressure backflow assembly (RP) low hazard only.
"Backpressure"means water pressure which exceeds the operating pressure of the public potable water supply system.
"Backsiphonage"means a drop in distribution system pressure that would cause, or tend to cause, water to flow opposite of its intended direction.
"Check valve"means a valve that allows the flow of fluids in only one direction.
"Contamination"means an impairment of the quality of the potable water by any physical, chemical, biological, or radiological substance that would present unreasonable risk to public health. Also referred to as a "high hazard."
"Cross-connection"means a point in the plumbing system where the public potable water supply is connected directly, or has the potential of being connected, to an auxiliary water source or a nonpotable substance that is not a part of the public potable water supply.
"Cross-connection specialist"means a person certified by the Oregon Health Authority and authorized by the City of Harrisburg to administer the cross-connection control program and conduct cross-connection inspections and surveys.
"Degree of hazard"means either pollution (low hazard) or contamination (high hazard), classifications that shall be attached to all actual or potential cross-connections by the City of Harrisburg's cross-connection specialist.
"Double check valve assembly (DCVA)"means an assembly which consists of two independently acting check valves, loaded to the closed position by springs or weights and installed with shutoff valves on each side of the double check valve assembly and test ports for testing the assembly. This is the minimum protection required for fire sprinkler systems.
"Hazard, high (contamination)"means a condition, device or practice which is conductive to the introduction of waterborne disease producing organisms, harmful chemical, physical or radioactive substances into the City potable water supply and which presents an unreasonable risk to public health.
Hazard, Low.An actual or potential threat to the physical properties of the City water system with the maximum degree or intensity of pollution to which the potable water system could be degraded under this definition would cause a nuisance or be aesthetically objectionable.
"Potable water supply"means City supplied water which is safe for human consumption, free from harmful or objectionable materials as described and mandated by the Oregon Health Authority. City of Harrisburg potable water system includes all services, meters, reservoirs, wells, facilities and any equipment used in the process of producing, treating, storing or conveying water for public consumption.
"Potential cross-connection"means a cross-connection that would most likely occur, but may not be taking place at the time of an inspection.
"Pressure vacuum breaker assembly"means an assembly consisting of one or two spring-loaded check valves in the supply line, a spring-loaded air inlet on the downstream side of the check valve which will open to atmosphere when the pressure in the assembly drops below one pound per square inch, two shutoff valves, and two test ports for testing.
"Reduced pressure backflow assembly"(RPBA) means an assembly consisting of two independently operating check valves, spring-loaded to the closed position, separated by a spring-loaded differential pressure relief valve loaded in the open position, and installed as a unit with two resilient seat shutoff valves and suitable connections for testing. An RPBA is the most common device required by the city.
"Reduced pressure principle assembly (RP assembly)"means an assembly containing two independently acting approved check valves together with a hydraulically operating, mechanically independent pressure differential relief valve located between the check valves and at the same time below the first check valve. The unit shall include properly located test port and tightly closing shutoff valves at each end of the assembly. This assembly is designed to protect against a non-health hazard or a low health hazard.
"Thermal expansion"means pressure created by heated water or fluid that is not given room to expand.
Thermal Expansion Tank.An expansion tank or expansion vessel is a small tank used to protect closed (not open to atmospheric pressure) domestic hot water systems from excessive pressure.
(Formerly 13.20.010; Ord. 868 § 1, 2008; Ord. 924 § 1 (Exh. A), 2014; Ord. 961 § 1 (Exh. A), 2018)