Transcript Backflow Devices

Backflow Devices
5 Types
5 Main Types of Backflow Devices
• AVB – Atmospheric Vacuum Breaker
• PVB – Pressure Vacuum Breaker
• DCVA – Double Check Valve assembly
• RPP – Reduced Pressure Principle Backflow Preventer
• HCVB – Hose Connection Vacuum Breaker
AVB –Atmospheric Vacuum
Breaker
Always Downstream from the valve
PVB
Pressure Vacuum Breaker
Upstream from the valve(s).
Typically used for an In-line
Residential System. Or where
approved in commercial
situations by building codes.
DCVA -Double Check Valve
Assembly
2 shut off valves for redundant protection (one
will hold if other fails)
Usually commercial applications where a danger
of contamination from backflow is low. Ex.
Sprinkler systems
Reduced Pressure
Principle Assembly is
designed for installation on
potable water lines to protect
against both backsiphonage
and backpressure of
contaminated water into the
potable water supply.
Assembly shall provide
protection where a potential
health hazard exists
There sometimes has to be some kind of a drain below relief valve to avoid
staining or erosion
In some cases tandem antisiphon devices are put in place in case one fails
or needs to be worked on the system is still protected by the other
HCVB – Hose Connection
Vacuum Breaker
5 Main Types of Backflow Devices
• AVB – Atmospheric Vacuum Breaker - Must be
downstream of valve to work (one for each valve)
• PVB – Pressure Vacuum Breaker – Usually for residential or
small commercial in-line irrigation systems
• DCVA – Double Check Valve Assembly – Redundant
check valves usually for systems with out risk of contamination ex. Fire
Sprinkler Systems, Some irrigation systems
• RPP – Reduced Pressure Principle Backflow
Preventer -2 check valves with a central chamber held at a
lower pressure. Used for protection in higher risk situations
where chemicals or contaminants are present often on site.
• HCVB – Hose Connection Vacuum Breaker – protects
potable water from hose water (“Squirts in your face or on your clothes
when you turn off the hose”)
Angle valve
Globe/In-line valve