ASSE 5130 key terms

Any actual or potential link between a potable water supply and a source of contamination or pollution, creating a path by which non-potable material could enter the drinking water system.

The unwanted reverse flow of water, or of other substances, through a piping arrangement into the potable distribution system, caused by backsiphonage or backpressure conditions.

Backflow produced by a negative or reduced pressure in the supply piping, which draws non-potable liquid into the system through a cross-connection, as during a main break or heavy demand.

Backflow caused by downstream pressure exceeding the pressure of the potable supply, commonly created by pumps, boilers, elevation differences, or compressed gas pushing fluid backward.

A condition that degrades water quality but does not by itself create a health hazard, such as cloudiness, odor, or objectionable taste; a lower degree of hazard than contamination.

The introduction of any substance into potable water that creates an actual hazard to public health, such as sewage, toxic chemicals, or disease-causing organisms.

The classification of a cross-connection as either high or low based on whether the potential contaminant poses a health risk or only an aesthetic or quality nuisance.

A physical separation between the free-flowing discharge end of a potable supply pipe and the flood level rim of a receiving vessel, providing the highest protection against backflow.

A testable backflow preventer using two independently acting check valves with a hydraulically operated differential relief valve between them, giving high-hazard protection without an air gap.

A testable assembly of two independently acting check valves in series, used to protect against low-hazard, non-health-threatening pollution where backpressure is not severe.

A testable assembly with a loaded air inlet valve on the discharge side of a check valve, protecting against backsiphonage but not backpressure, and requiring installation above the highest downstream outlet.

A non-testable device with a float or disc that opens to atmosphere when supply pressure drops, preventing backsiphonage; it must be installed above the flood level and cannot be pressurized.

A vacuum breaker assembly designed to discharge only minimal water from its air inlet during normal operation, allowing installation in areas where spillage would otherwise be a concern.

A valve that permits flow in only one direction and closes automatically when flow reverses, forming the core component of most testable backflow prevention assemblies.

The differential-pressure-operated valve in a reduced pressure principle assembly that opens to discharge water when the pressure between the check valves approaches supply pressure, signaling a fault.

The opening on a vacuum breaker that admits atmospheric air into the assembly when internal pressure drops, breaking the vacuum that would otherwise cause backsiphonage.

The edge of the receptacle or fixture from which water overflows, used as the reference point for measuring the required air gap or installation height of a vacuum breaker.

The marked elevation on a vacuum breaker or backflow device that must be installed at or above the flood level rim of the fixture served, per the manufacturer's listing.

The difference in pressure measured between two points in an assembly, such as across a check valve or across the relief valve seat, used to judge whether the device is holding properly.

A small, normally closed valve on a backflow assembly that allows a tester to attach gauges or bleed water to measure pressures at specific points during a field test.

The internal channel in a reduced pressure principle assembly that delivers supply-side pressure to the relief valve diaphragm, allowing it to react to changes in differential pressure.

A calibrated differential pressure gauge, typically with a 0–15 psi range and small graduations, used with hoses and test cocks to verify assembly performance in the field.

The movable sealing element inside a check valve or vacuum breaker that contacts the seat to stop flow; wear, debris, or deformation of the disc is a common cause of test failure.

The machined surface inside a valve against which the disc or clapper seals; nicks, scale, or wear on the seat cause leakage and require cleaning or replacement.

A circular elastomeric seal used at joints, stems, and bonnets of backflow assemblies to prevent external leakage; deterioration leads to drips and requires replacement during repair.

The removable cover or cap on a valve body that houses the stem and internal parts, allowing access for inspection, cleaning, and replacement of discs and springs.

Measures such as insulation, heat tracing, draining, or enclosure that keep a backflow assembly from freezing, since ice damage can crack bodies and ruin internal seals.

A cabinet or vault housing a backflow assembly, which must provide drainage, access for testing and repair, and protection from freezing, flooding, and unauthorized tampering.

The means of removing discharge from relief valves, test cock bleeding, and spills to a safe location, required so assemblies do not flood their enclosures or create hazards.

A systematic inspection of a property's plumbing and processes to identify cross-connections, classify hazards, and determine the appropriate backflow prevention method for each point of use.

Protection installed at the service connection or property boundary to isolate the entire premises from the public main, typically required where internal hazards cannot be individually controlled.

Point-of-use backflow protection installed at an individual fixture, appliance, or process within a building, protecting the internal piping rather than the public supply.

The recurring field verification, usually required at least once a year by the water authority, that a testable backflow assembly meets its specified performance values.

The documented record of an assembly test listing device type, location, serial number, gauge readings, pass or fail result, tester identity, and date, submitted to the authority.

The process of recording a backflow assembly with the water purveyor, assigning an identification number and tracking its location, test history, and compliance status.

Formal credentialing, often through a recognized training program and examination, that authorizes an individual to test backflow prevention assemblies within a jurisdiction.

Safety gear such as gloves, eye protection, and footwear worn while testing or repairing assemblies to guard against pressurized water, chemicals, and contaminated discharge.

The evaluation of what contaminant or pollutant a cross-connection could introduce and how severe the health effect would be, guiding selection of the proper protection level.