Term

Definition
AS/NZS 3500.1
 Australian Standard Plumbing & Drainage – Water Supply
AS/NZS 2845.1
 Australian Standard Water Supply – Backflow Prevention Devices –

Part 1 :  Materials, Design and Performance Standards
AS 2845.2
 Australian Standard Water Supply – Backflow Prevention Devices –

Part 2 :  Air Gaps and Break Tanks
AS 2845.3
 Australian Standard Water Supply – Backflow Prevention Devices –

Part 3 :  Field Testing and Maintenance
Accredited Person/Tester
 Licenced plumber holding accreditation from a Registered Training Authority for backflow prevention device commissioning and certification
Alternative Water Supply
 Water from a source other than the water supplied from the Public authority potable water supply
AS/NZS 3500
 Australian/New Zealand Standard 3500 for pluming and Drainage Part 1
Backflow
 Backflow is the unintended flow of water from any domestic, industrial or institutional piping system into a drinking water supply system.  It can be caused by a loss of pressure in the drinking water supply main or by the flow from a pressurised system through an unprotected cross connection
Backflow prevention device (BPD)
 A device to prevent the reverse flow of water from a potential contaminated source, into the drinking water supply.
Back Pressure
 Is when the pressure in the customers internal plumbing system is greater than the pressure in the Public authority potable water supply.
Back Siphonage
 Occurs when the pressure in the Public authority potable water supply’s supply falls below atmospheric pressure, thus sucking water from the customer’s internal plumbing system into the water supply main.
Boundary Protection
 An approved backflow prevention device installed at the property boundary to protect the Public authority water supply.
Cross connection
 Any connection or arrangements between the systems, connected to the water main or any fixture that may enable non-drinking water or other contamination to enter the system
Customer
 The property owner who is connected to a water main
Drinking Water Supply
 The supply system into which an authority delivers drinking water
DCV
 Double Check Valve – a testable device designed for use in medium hazard conditions to prevent backflow caused by back siphonage or back pressure
DuCV
 Dual Check Value – A non-testable device designed for use in low hazard conditions to prevent backflow caused by back siphonage or back pressure.  Some valves may incorporate an atmospheric vent.
High Hazard
 Any condition, device or practice that, in connection with a drinking water supply system, has the potential to cause death
Low Hazard
 Any condition, device or practice that, in connection with a drinking water supply system, constitutes a nuisance but does not endanger health
Medium Hazard
 Any condition, device or practice that, in connection with a drinking water supply system, has the potential to endanger health
Potable water
 Water that is suitable for drinking by humans
Reduced Pressure Zone Device (RPZD)
 A testable device designed for use in High Hazard conditions to prevent backflow caused by back siphonage or back pressure.  It is two independently operating force load non-return valves installed in series and a relief valve positioned between the non-return valves, it incorporates specific test taps for in-service testing.
Registered Air Gap
 Is an approved method of achieving backflow compliance and is the unobstructed vertical distance through free atmosphere between the lowest opening of a water supply pipe and the highest possible water level in the receiving tank or vessel.
Registered Break Tank
 A tank installed to satisfy backflow requirements, the tank incorporates an air gap, see ‘Registered Air Gap’
Recycled Water
 Highly treated wastewater that can be used in industrial processes, to irrigate agriculture, urban parks and landscapes, and in the home for flushing toilets, car washing and watering gardens.  Water not used for drinking or personal use.
Single Check Valve (SCV)
 A testable device designed for use in Low Hazard conditions to prevent backflow caused by back siphonage or back pressure, it is specifically designed for use with fixed fire services.  It has a single force loaded non-return valve installed and incorporates specific test taps for in-service testing.
Site containment
 The installation of a backflow prevention device on the drinking water supply system at the property boundary, to prevent backflow from within the property entering the supply system
Zone Protection
 Is an approved backflow prevention device installed on a specific section of the customer’s internal plumbing system to protect a ‘zone’ or specific section.