(1) Air gap (AG): The unobstructed vertical distance through the free atmosphere between the opening of the pipe or faucet supplying potable water to a tank, plumbing fixture or other device. An approved air gap shall be at least double the effective opening of the supply pipe or faucet and in no case less than one (1) inch above the flood rim.
(2) Reduced pressure principle assembly (RPA): An assembly containing two (2) 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 assembly shall include properly located test cocks and tightly closing shutoff valves located at each end of the assembly.
(3) Double check valve assembly (DCVA): An assembly composed of two (2) independently acting, approved check valves, including tightly closing shutoff valves located at each end of the assembly and fitted with properly located test cocks.
(4) Pressure vacuum breaker assembly (PVB): An assembly containing an independently operating, loaded check valve and an independently operating, loaded air inlet valve located on the discharge side of the check valve. The assembly shall be equipped with properly located test cocks and tightly closing shutoff valves located at each end of the assembly.
(5) Spill-resistant pressure vacuum breaker (SVB): An assembly containing an independently operating internally loaded check valve and independently operating loaded air inlet valve located on the discharge side of the check valve. The assembly shall be equipped with a properly located resilient seated test cock, properly located bleed/vent valve and tightly closing resilient seated shutoff valves located at each end of the assembly.
(6) Double check detector assembly (DCDA or DDCVA): An assembly composed of a line size approved double check valve assembly with a bypass containing a specific water meter and an approved double check valve assembly.
(7) Reduced pressure principle detector assembly (RPDA): An assembly composed of a line size approved reduced pressure principle assembly with a bypass containing a specific water meter and an approved reduced pressure principle assembly.
(b) A backflow prevention method may be approved by Tucson Water if it is contained in section 7.2 of the Manual of Cross-Connection Control, Ninth Edition, USC- FCCCHR, KAP-200 University Park MC 2531, Los Angeles, California, 90089-2531, December 1993 (cross connection manual). The current list of approved methods shall be available for inspection at Tucson Water to any customer required to install a backflow prevention assembly.
(c) Any backflow prevention assembly equipped with test cocks shall have been issued a certificate of approval by the USC Foundation for Cross-Connection Control and Hydraulic Research or a third-party certifying entity that is unrelated to the product's manufacturer or vendor, and is approved by the Arizona Department of Environmental Quality. Any backflow prevention assembly not equipped with test cocks shall be certified by a third party entity unrelated to the product's manufacturer or vendor and approved by the Arizona Department of Environmental Quality.
(Ord. No. 9976, § 2, 5-24-04; Ord. No. 10867, § 1, 12-21-10)