LHAP 302 Point of Connection and BFPD's

Slide 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 Slide 2 Point of Connection M W Slide 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. Slide 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 Slide 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 Slide 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. Slide 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 Slide 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 Slide 9 Pressure Vacuum Breaker Install 30cm above highest outlet Slide 10 PVB operation Slide 11 Dual Check Valve cannot be pressure checked rely on 2 spring loaded check valves installed in line on supply side of valve Slide 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 Slide 13 Double Check Valve Slide 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 Slide 15 Reduced Pressure Vacuum Breaker Slide 16 RPZ Vacuum Breaker - installation Slide 17 Reduced Pressure Vacuum Breaker (RPZ) How they WORK