Backflow Tester flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Cross-connection

Any actual or potential physical link between a potable water supply and a source of nonpotable fluid or contaminant that could allow backflow into the drinking water system.

Backsiphonage

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

Backpressure

Backflow caused when pressure downstream of a cross-connection exceeds the supply pressure, pushing nonpotable fluid backward into the potable water system.

Pollution hazard

A cross-connection condition that degrades water quality aesthetically or otherwise but does not create a health hazard, typically requiring only non-health-hazard protection.

Contamination hazard

A cross-connection condition introducing substances that create a health hazard, requiring the highest level of protection such as an air gap or reduced pressure assembly.

Air gap

A physical separation between the potable outlet and the flood-level rim of a receiving vessel; minimum is two times the effective opening, never less than one inch.

Flood-level rim

The elevation at which water would overflow the receiving vessel or fixture, used to set the required vertical separation for an air gap.

Atmospheric vacuum breaker

A non-testable device with an air inlet that opens on backsiphonage; it may not be under continuous pressure for more than 12 hours and has no downstream shutoff.

Pressure vacuum breaker

A testable assembly with a loaded air-inlet check that must be installed at least 12 inches above the highest downstream outlet and protects against backsiphonage only.

Reduced pressure assembly

A testable assembly with two independent checks and a differential relief valve that protects against both backpressure and backsiphonage for health hazards.

Double check valve assembly

A testable assembly of two independent check valves used only for non-health-hazard protection against both backpressure and backsiphonage.

Spill-resistant PVB

A pressure vacuum breaker design that limits water discharge from the air inlet when the device is fouled, allowing installation where flooding would otherwise be unacceptable.

Hose-bibb vacuum breaker

A small non-testable device threaded onto a hose bibb that opens an air inlet on backsiphonage and must not be under continuous pressure or have a downstream shutoff.

Dual check valve

A non-testable two-check device used only for low-hazard protection, commonly at the meter or an appliance, and not accepted for health-hazard cross-connections.

Test cock

A small valved port on a backflow assembly used to connect test gauges and to bleed water so pressures at each check can be measured.

Differential pressure check

The pressure difference a check valve holds between its upstream and downstream sides, measured with a differential gauge to confirm the check seals properly.

Static line pressure

The supply pressure recorded at the upstream test cock with no flow through the assembly, used as the baseline for evaluating test results.

Check 1 differential

The pressure drop held across the first check of an assembly; a passing result requires it to remain at or above the specified minimum, commonly 1.0 psi.

Check 2 differential

The pressure drop held across the second check of a double check or reduced pressure assembly, measured separately and required to meet the minimum.

Relief valve opening point

The pressure differential at which the reduced pressure assembly relief valve begins to discharge, required to open at 2.0 psi or greater.

Air-inlet opening point

The differential pressure at which a pressure vacuum breaker air inlet opens to atmosphere, required to be 1.0 psi or greater on a passing test.

High side connection

The test gauge port connected upstream of the check being tested, so the gauge reads the higher of the two pressures during the measurement.

Low side connection

The test gauge port connected downstream of the check being tested, allowing the gauge to display the difference between upstream and downstream pressure.

Gauge calibration

Verification of test instrument accuracy against a known reference, required at least annually so recorded differentials are reliable and defensible.

Test report contents

Documentation including assembly make, model, size, serial number, location, static pressure, measured differentials or opening points, pass or fail, tester identity, and date.

Failed assembly tag

A notice placed on an assembly that fails testing, indicating it is out of service pending repair or replacement and notifying the purveyor and owner.

Retest after repair

A complete repeat of the assembly test performed after repair or replacement to confirm the device now meets all required differential and opening-point criteria.

Continuous pressure limit

The rule that an atmospheric vacuum breaker may not be subjected to supply pressure for more than 12 hours, since prolonged pressure can damage the air-inlet seal.

Test sequence RP assembly

Order of measurement for a reduced pressure assembly: check 1 differential, then check 2 differential, then the relief valve opening point.

Bleed to open relief

A test step in which the low-side gauge is slowly bled to reduce downstream pressure until the relief valve discharges, revealing the opening differential.

Purveyor notification

The requirement to report a failed or removed assembly to the water purveyor, typically within a set time, so the cross-connection program record stays current.

Tester certification

The credential, issued after written and practical examination, that authorizes a person to test backflow prevention assemblies and sign test reports.