ASSE 6020 key terms

Any actual or potential physical link between a potable water supply and a source of contamination or pollution, through which backflow could move undesirable substances into drinking water.

The unwanted reversal of water flow from its intended direction, carrying nonpotable water or other substances into a potable piping system.

Backflow caused by negative or sub-atmospheric pressure in the supply piping, which draws contaminants into the system through a cross-connection.

Backflow resulting from downstream pressure that exceeds the pressure of the potable supply, pushing water backward through a cross-connection.

The unobstructed vertical distance between the lowest opening of a water outlet and the flood level rim of the receiving vessel; the highest-level fixed backflow protection.

The edge of the receptacle from which water overflows, used as the reference point for measuring air gaps and establishing minimum installation heights for vacuum breakers.

A testable backflow preventer with two independently acting check valves and a hydraulically operated differential relief valve, used where both backpressure and backsiphonage hazards exist.

A testable assembly of two independently acting check valves used to protect against backflow hazards that are not health hazards, such as low-hazard pollution connections.

A testable assembly containing a spring-loaded check valve and an air-inlet valve that opens to atmosphere when supply pressure drops, protecting against backsiphonage only.

A non-testable device with an air-inlet valve that admits air when supply pressure falls, used on noncontinuous-pressure, backsiphonage-only applications such as hose bibbs.

A valve that permits flow in one direction only and closes automatically to prevent reversal, forming the core component of many backflow prevention assemblies.

The diaphragm-operated relief port in a reduced pressure principle assembly that discharges water when the pressure differential between zones is lost, protecting against both backflow types.

The marked or established elevation on a vacuum breaker or similar device to which the unit must be installed above all downstream piping and outlets to prevent spillage or contamination.

The pressure relationship between the inlet, first intermediate zone, and second intermediate zone of a reduced pressure principle assembly that keeps the relief valve seated during normal flow.

A small valved opening on a backflow assembly that allows a tester to connect gauges, read zone pressures, and bleed air or water during field testing.

A test instrument with two hoses and a sensitive gauge that measures the pressure difference across check valves and zones of a backflow prevention assembly during field testing.

The documented record of an assembly's test results, including serial number, gauge readings, pass or fail status, tester identity, and date, submitted to the water authority.

The recurring requirement that testable backflow prevention assemblies be verified by a certified tester at least once each year or at the interval set by the local authority.

A person who has completed recognized training and passed an examination demonstrating competence to test backflow prevention assemblies and submit valid field test reports.

Backflow prevention installed at the service connection or property line to isolate the entire premises from the public water system, protecting the distribution main from site hazards.

Point-of-use backflow prevention installed at individual fixtures or pieces of equipment within a facility, supplementing rather than replacing containment protection.

The organized local effort to identify hazards, require appropriate protection, track assemblies, verify testing, and enforce compliance through a public water system's authority.

The process of rating a cross-connection as a health hazard or non-health hazard to determine the minimum type of backflow protection required at that location.

A cross-connection condition that could introduce contaminants capable of causing illness or disease, requiring the highest degree of protection such as an air gap or reduced pressure assembly.

Pressure buildup caused by heated water expanding in a closed system, which can damage assemblies and cause relief valve discharge when a backflow preventer is installed.

A piping arrangement with no open outlet or relief path, where thermal expansion or pressure surges can stress components and require a thermal expansion control device.

A pressure surge caused by a sudden change in flow velocity, such as rapid valve closure, that can damage backflow assemblies and cause nuisance relief valve discharge.

Water escaping from the relief port of a reduced pressure principle assembly during normal operation, usually indicating debris, worn seals, or a damaged check valve.

A manufacturer-supplied set of replacement parts, such as seats, springs, diaphragms, and check assemblies, used to restore a backflow preventer to proper operating condition.

Measures such as insulation, enclosures, or drain-down procedures that prevent water in a backflow assembly from freezing and cracking its body or internal components.

The severity of risk posed by a cross-connection, ranging from pollution that degrades quality to contamination that endangers health, which sets the required protection level.

A foreign substance in water that lowers its quality or appearance but does not create a health risk, typically addressed with double check valve protection.

Any substance that, if introduced into potable water, could cause illness, disease, or death, distinguishing a health hazard from a mere aesthetic problem.

The pipe linking a public water main to a customer's plumbing, often the required location for containment backflow prevention in a cross-connection control program.

Protecting the public supply by installing a testable assembly at the meter or property line so that all on-site hazards are contained within the customer's system.

A consensus document such as the Uniform Plumbing Code or International Plumbing Code that establishes cross-connection control and backflow prevention requirements adopted by jurisdictions.

The organization or official empowered to adopt, interpret, and enforce cross-connection control rules, approve assembly installations, and require corrective action.

A backflow prevention device or assembly listed by a recognized testing organization and accepted by the local authority for the specific hazard and installation conditions.