Pressure vacuum breaker

Backflow prevention device

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 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, but may also be required by government regulations.

v t e Plumbing
Fundamental concepts	Air gap (plumbing) Backflow Compatibility (chemical) Corrosion Drain (plumbing) Drinking water Fuel gas Friction loss Grade (slope) Greywater Heat trap Hydrostatic loop Leak Neutral axis Onsite sewage facility Pressure Sanitary sewer Sewer gas Sewage Sewerage Siphon Storm sewer Stormwater Surface tension Tap water Thermal expansion Thermal insulation Thermosiphon Trap (plumbing) Venturi effect Wastewater Water hammer Water supply network Water table Well
Technology	Brazing British Standard Pipe (BSP) Cast iron pipe Chemical drain cleaners Compression fitting Copper tubing Crimp (joining) Drain-waste-vent system Ductile iron pipe Flare fitting Garden Hose Thread (GHT) Gasket Hydronics Leak detection National Pipe Thread (NPT) Nominal Pipe Size (NPS) O-ring Oakum Pipe (fluid conveyance) Pipe dope Pipe support Plastic pipework Push-to-pull compression fittings Putty Sealant Sewage pumping Soldering Solvent welding Swaging Thread seal tape Threaded pipe Tube bending Water heat recycling
Components	Atmospheric vacuum breaker Automatic bleeding valve Automatic faucet Backflow prevention device Ball valve Bleed screw Booster pump Butterfly valve Check valve Chemigation valve Chopper pump Circulator pump Cistern Closet flange Concentric reducer Condensate pump Coupling (piping) Diaphragm valve Dielectric union Double check valve Eccentric reducer Expansion tank Faucet aerator Float switch Float valve Floor drain Flow limiter Flushing trough Flushometer Gate valve Globe valve Grease trap Grinder pump Hose coupling Manifold Needle valve Nipple (plumbing) Pinch valve Piping and plumbing fitting Plug (sanitation) Pressure regulator Pressure vacuum breaker Pressure-balanced valve Pump Radiator (heating) Reduced pressure zone device Reducer Relief valve Riser clamp Rooftop water tower Safety valve Sewage pump Street elbow Submersible pump Tap (valve) Thermostatic mixing valve Trench drain Vacuum breaker Vacuum ejector Valve Water tank Zone valve
Plumbing fixtures	Accessible bathtub Bathtub Bidet Dehumidifier Dishwasher Drinking fountain Electric water boiler Evaporative cooler Flush toilet Garbage disposal unit Hot water storage tank Humidifier Icemaker Instant hot water dispenser Laundry tub Shower Sink Storage water heater Sump pump Tankless water heater Urinal Washing machine Washlet Water dispenser Water filter Water heater Water softener
Specialized tools	Basin wrench Blowtorch Borescope Core drill Drain cleaner Driving cap Flare-nut wrench Pipecutter Pipe wrench Plumber's snake Plumber wrench Plunger Strap wrench Tap and die
Measurement and control	Control valve Flow sensor Pressure sensor Water detector Water metering
Professions, trades, and services	Hydronic balancing Hydrostatic testing Leak detection Mechanical, electrical, and plumbing Pipe marking Pipefitter Pipelayer Plumber
Industry organizations and standards	International Association of Plumbing and Mechanical Officials (IAPMO) NSF International Plumbing & Drainage Institute (PDI) Uniform Plumbing Code (UPC) World Plumbing Council (WPC)
Health and safety	Plumbing code Scalding Waterborne disease
See also	Fire sprinkler system Piping Template:HVAC Template:Public health Template:Sewerage Template:Toilets Template:Wastewater