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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 (RP), reduced pressure principle backflow prevention devices , [ 1 ] [ 2 ] reduced pressure zone assemblies (RPZA), [ 3 ] or reduced pressure ...
Water pressure may fail or be reduced when a water main bursts, pipes freeze, or there is unexpectedly high demand on the water system (for example, when several fire hydrants are opened). Reduced pressure in the pipe may allow contaminated water from the soil , from storage, or from other sources to be drawn up into the system.
This arrangement prevents any contaminants in the sink from entering into the potable water system by siphonage; this is the simplest form of backflow prevention. A common use of the term "air gap" in domestic plumbing refers to a specialized fixture that provides backflow prevention for an installed dishwasher .
A recent introduction to the UK has been the Reduced Pressure Zone (RPZ) valve, a form of double check valve where the intervening zone is drained and normally kept empty. [1] If the downstream valve leaks and permits backflow, this will drain out through the vent rather than building up pressure against the upstream valve.
It is usually constructed of brass and resembles a 90-degree elbow with a hood on its top to allow air to enter the water system if a siphon attempts to form. Inside this elbow is a poppet valve that is held "up" by the water pressure found in the system, closing the air entrance to the device. If the pressure in the "upstream side" is reduced ...
Reduced pressure zone device, a type of backflow prevention device Response policy zone , a mechanism for use by Domain Name System recursive resolvers Residents parking zone , practice of designating certain on-street car parking spaces for the exclusive use of nearby residents
Such an irrigation system must not be connected to any potable water supply except through a reduced pressure principle backflow prevention assembly." Florida's Department of Agriculture and Consumer Services Water Quality/Quantity Best Management Practices for Florida Specialty Fruit and Nut Crops [ 2 ] p. 20 specifies that:
A pressure vacuum breaker (PVB) is a type of backflow prevention device, used to keep non-potable (or contaminated) water from entering the water supply. A PVB is similar to an atmospheric vacuum breaker (AVB), except that the PVB contains a spring-loaded poppet. This makes it acceptable for applications that are high hazard or where valves are ...