1. Backflow Devices
5 Types

2. 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

3. AVB –Atmospheric Vacuum Breaker
Always Downstream from the valve

4. 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.

6. 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

8. 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

9. There sometimes has to be some kind of a drain below relief valve to avoid staining or erosion

12. 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

13. HCVB – Hose Connection Vacuum Breaker

14. 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”)

15. Angle valve

16. Globe/In-line valve