A pressure vacuum breaker (PVB) is a type of
backflow prevention device
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, ...
, used to keep non-
potable
Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often (but not always) supplied through taps, in which case it is also calle ...
(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
In folk magic and witchcraft, a poppet (also known as poppit, moppet, mommet or pippy) is a doll made to represent a person, for casting spells on them, or aiding that person through magic. They are occasionally found lodged in chimneys. These dol ...
. This makes it acceptable for applications that are high hazard or where valves are downstream. Pressure vacuum breakers must be protected from freezing when installed outdoors. PVBs usually have test cocks, to which specially-calibrated gauges are attached, in order to ensure that they are functioning properly.
Backflow prevention devices such as PVBs are regulated by the
Uniform Plumbing Code
Designated as an American National Standard, the Uniform Plumbing Code (UPC) is a model code developed by the International Association of Plumbing and Mechanical Officials ( IAPMO) to govern the installation and inspection of plumbing system ...
, but may also be required by government regulations.
See also
*
Air gap
*
Atmospheric vacuum breaker
*
Chemigation valve
Sometimes called a check valve or a backflow preventer, a chemigation valve is an apparatus designed to protect water supplies from agricultural chemicals used during chemigation, the application of chemicals such as fertilizers and pesticides thro ...
*
Double check valve
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination.Dietmar Findeisen (2005) ''Ölhydraulik: Handbuch für die hydrostatische Leistungsübertragung in der Flu ...
*
Hydrostatic loop
*
Reduced Pressure Principle BFP
References
{{DEFAULTSORT:Pressure Vacuum Breaker
Plumbing valves
Irrigation
Backflow