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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 principle ...
A backflow prevention device is used to protect potable water supplies from contamination or pollution due to backflow. In water distribution systems, water is normally maintained at a significant pressure to enable water to flow from the tap, shower, or other fixture. Water pressure may fail or be reduced when a water main bursts, pipes freeze ...
Texas State law Chapter 344.73 in Subchapter D - 1.(b) [citation needed] "An irrigation system which adds any chemical is considered to be a 'high health hazard'. Such an irrigation system must not be connected to any potable water supply except through a reduced pressure principle backflow prevention assembly."
If the pressure in the "upstream side" is reduced to atmospheric pressure or below, the poppet valve drops and allows air to enter the system, breaking the siphon. [1] One-Inch Brass Atmospheric Vacuum Breaker mounted on PVC Pipe. These devices, since they work on atmospheric principles, cannot be installed in an enclosure containing air ...
Backflow occurs for one of two reasons, either back pressure or back siphonage. [1] Back pressure is the result of a higher pressure in the system than in its supply, i.e. the system pressure has been increased by some means. This may occur in unvented heating systems, where thermal expansion increases the pressure.
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. [1] It is different from the two-way check valves (sometimes erroneously referred to as double check valves) used in air brake systems on heavy trucks which select from the highest pressure source.
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 ...
An air gap, as related to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture. [1] Air gaps of appropriate design are legally required by water health and safety regulations in many countries. An air gap is the simplest form of a backflow prevention device.