LHAP 302 Point of Connection and BFPDs

1. Point of Connection

The main components of a residential / light commercial block system are:

• Controller

Point of connection (POC) Valve manifold Pipe Sprinklers or micro-emitters

Other components may include

• Filtration
• Pressure regulation

2. Point of Connection

• M W

3. Backflow Prevention Devices

required by local Municipal Health Codes prevents contamination of water supplies from irrigated water moving backwards through the irrigation system and into the domestic water line.

4. Backflow Prevention

Atmospheric Vacuum Breaker (AVB) Pressure Vacuum Breaker (PVB)

• Dual check Valve
• Double Check Valve

Reduced Pressure Backflow Device (RP or RPZ) 5 basic types

5. Atmospheric Vacuum Breaker (AVB)

simplest form of BFPD relies on gravity to close a gate prevent back siphoning and backflow (not back pressure) should not be used where the device is under pressure for long periods of time cannot be pressure checked

6. Atmospheric Vacuum Breaker

must be installed 150mm above the highest downstream sprinkler and on the sprinkler side of any valve.

Typically there is one AVB for every zone.

7. Hose Connection

attached to hose bib provide minimal backflow and back pressure when the water is shut off a spring loaded check valve inside closes

8. Pressure Vacuum Breaker (PVB)

Popular in the 1960-80’s spring loaded used more in areas where winter temperatures are not as low installed on supply side of control valve

9. Pressure Vacuum Breaker

• Install 30cm above highest outlet

10. PVB operation

11. Dual Check Valve

cannot be pressure checked rely on 2 spring loaded check valves installed in line on supply side of valve

12. Double check Valve

a bigger stronger version of the dual check valve can be pressure checked most common in residential installs- only use for low hazard applications protect against back siphon and back pressure installed on supply side of control valve - can be under constant pressure

13. Double Check Valve

14. Reduced Pressure Vacuum Breaker (RPZ)

has a chamber between the 2 check valves that is normally 2 psi below operating pressure change in pressure causes valves to close used in many municipalities

15. Reduced Pressure Vacuum Breaker

16. RPZ Vacuum Breaker - installation

17. Reduced Pressure Vacuum Breaker (RPZ)

• How they WORK