Backflow Basic Types of Prevention Devices Testable I-2 Backflow Preventers

Reduced Pressure Zone (RPZ) Testable Double Check Backflow Preventer Valve Assembly Purpose Purpose For high hazard cross-connections and continuous For low hazard cross-connections and continuous pressure applications. pressure applications.

Description of Backflow Device Description of Backflow Device Two independent check valves with intermediate dump- ing relief valve, shut-off valves, and ball type test cocks. Two independent check valves with shut-off valves and ball type test cocks.

Applications Applications Reduced Pressure Backflow Devices should be used Double Check Valve Assemblies may be used where whenever the non-potable source is more of a contaminant the degree of hazard is low to intermediate, meaning that than a pollutant. Basically, they are applied as main line the non-potable source is polluted rather than contaminated. protection to protect the municipal water supply, but should The degree of hazard is often determined by local Inspec- also be used on branch line applications where non-potable tion Departments and therefore such departments should fluid would constitute a health hazard, such as boiler feed be questioned in order to comply with local regulations. lines, commercial garbage disposal systems, industrial boilers (see typical installations below). Where to Use Where to Use A Double Check Valve Assembly may be used as Reduced Pressure Zone Devices may be used on protection of all direct connections through which foreign all direct connections which may be subjected to back- material might enter the potable system in concentration pressure or back-siphonage, and where there is the and which would constitute a nuisance or be aesthetically possibility of contamination by the material that does objectionable, such as air, steam, food or other material constitute a potential health hazard. which does not constitute a health hazard. Typical Installations: Typical Installations: • Main Supply Lines • Laboratory Equipment • Main Supply Lines • Commercial Boilers • Waste Digesters • Food Cookers • Cooling Towers • Car Washes • Tanks and Vats • Hospital Equipment • Sewage Treatment • Lawn Sprinklers • Processing Tanks • Fire Sprinkler Lines

MAIN

WATTS NO. 909

STRAINER

AIR GAP

TANK TANK TANK TANK

H-2I-2 Phone: 800-EJP-24HR (357-2447) • Fax: 207-582-5637 www.ejprescott.com