A Reduced Pressure Zone Device (RPZD, RPZ or RPZ valve) is a type of backflow prevention device used to protect water supplies from contamination. RPZDs may also be known as reduced pressure principle backflow prevention devices, or reduced pressure zone assemblies.An RPZD is considered suitable for high hazard applications, that is, where the consequence of backflow into the water supply would cause significant harm. They are considered suitable because they prevent both backflow and back-siphonage, because of a redundant design (even with two check valves broken the device still provides protection), and because they are testable to verify correct operation.

Series 909S-AUS prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage or backpressure where there is a potential health hazard. An exclusive relief valve design provides substantially improved relief valve discharge performance during emergency conditions of combined backsiphonage and backpressure. These small diameter backflow preventers are available in DN15 to DN50 sizes. Series 909S-AUS for small diameter assemblies has a compact modular design that facilitates easy maintenance for in-line repairs. It can be installed horizontal or vertical without the need of any special tools.

Series 909S-AUS prevents the reverse flow of polluted water from entering into the potable water supply due to backsiphonage or backpressure where there is a potential health hazard. An exclusive relief valve design provides substantially improved relief valve discharge performance during emergency conditions of combined backsiphonage and backpressure. These small diameter backflow preventers are available in DN15 to DN50 sizes. Series 909S-AUS for small diameter assemblies has a compact modular design that facilitates easy maintenance for in-line repairs. It can be installed horizontal or vertical without the need of any special tools.

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