Backflow Testing Definitions

Air Gap (AG):
The definition of an air gap is the unobstructed vertical distance between the lowest opening from any pipe or faucet conveying water or waste to a tank, plumbing fixture, receptor, or other vessel and the flood level rim of the receptacle. These vertical, physical separations must be at least twice the diameter of the water supply outlet, never less than 25 mm (one inch) and/or in accordance with any local codes and regulations.

Alarm check (non-approved backflow preventer):
A single, soft seated check valve which may or may not be internally loaded will sound an alarm when the check valve opens. The alarm check shall have suitable connections for testing the water tightness and operation of the check valve.

Area Protection
:
Protection provided for a piping system section with potable and non-potable connections downstream of a backflow preventer.

Atmospheric Pressure:
The pressure exerted by the atmosphere at any point. Such pressure decreases as the elevation of the point above sea level increases. One atmosphere is equivalent to 101.4kPa (14.7 psi), 760mm (29.92in) of mercury, or 10.1 m(33.9 ft) of water column at average sea level.

Atmospheric Vacuum Breaker (AVB):
A device consisting of an inlet shut off valve followed by a valve body containing a vacuum relief valve(poppet), vacuum relief valve seat, a check valve seat, and an atmospheric vent.
The AVB is designed to allow air to enter the downstream water line to prevent backsiphonage.

Auxiliary Water Supply:
Any water source or system other than the public water supply, that may be available in building or on a premise.

Backflow:
Backflow is the flow of water or other liquids back into the potable water system.

Backflow Preventer:
An assembly or device which prohibits the backflow of water into the potable water supply.

Backpressure:
A pressure, higher than the supply pressure, caused by a pump elevated tank, boiler or any other means which may cause backflow.

Backsiphonage:
Backflow caused by negative or reduced pressure in the supply piping.

Barometric Loop:
A piping arrangement which is formed in a loop rising 10.7 meters(35 ft) above the highest fixture being serviced.

Certified Backflow Prevention Assembly Tester:
A person who is certified by the approving authority to Test, Repair and Maintain Backflow Prevention Assemblies.

Consumer:
The term consumer shall mean the owner or operator having a service from a public potable water system.

Contamination:
An impairment of a potable water supply by the introduction or admission of any foreign substance which degrades the quality and/or creates a hazard.

Critical Level:
Critical Level means the level of submergence at which the backsiphonage preventer ceases to prevent backsiphonage.

Cross Connection:

A connection or a potential connection between any part of a potable water system and any other environment containing other substances in a manner which under any circumstances, would allow such substance to enter the potable water system. Other substance may be gases, liquid or solids such as chemicals, waste products, steam, water from other sources(potable or non-potable), or any matter which may change the colour or add odour to the water.

Bypass arrangements, jumper connections, removable sections, swivel or change other devices or any other temporary or permanent connecting arrangement through which backflow may occur are considered to be cross connections.

Cross Connection Control:
The enforcement of an ordinance regulating cross connections.

Detector Check (non approved backflow preventer):
A single, internally loaded, soft seated main line check valve with a bypass consisting of a check valve and a water meter to detect small leakage or unauthorized use of water. Both check valves shall have suitable connections for testing the water tightness of each check valve.

Detector Double Check Valve Assembly (DDCVA):
An assembly that  combines the features of a detector check and an approved backflow preventer for installation on moderate hazard fire systems. This specially designed, factory built and tested assembly is composed of a main line double check valve

Assembly and a bypass consisting of a water meter and a double check valve assembly. Both assemblies shall have suitable connections for testing the water tightness of each valve. The DDCVA was designed as a dual purpose unit, it will detect leakage or unauthorized use of water from the fire systems and shall protect against objectionable backflow from a moderate fire system.

Double Check Valve Assembly (DCVA):

An assembly consisting of two internally loaded approved check valves, either spring loaded or internally weighted, installed as a unit between two tightly closing shutoff valves and having suitable
connections for testing the watertightness of each check valve.

Dual Check Valve Backflow Preventer (DuC):
A DuC is a device consisting of two independently acting seated check valves, internally force loaded to the normally closed position.

Dual Check With Atmospheric Port(DCAP):
A DCAP is a device consisting of two independently acting internally loaded check valves and an intermediate atmospheric vent.

Dual Check Valve Type with Atmospheric Port for Carbonators (DCAPC):
A DCAPC is a carbonated beverage backflow preventer consisting of two independently acting check valves biased to normally closed  positions and separated by an intermediate chamber with an atmospheric port. A chamber pressure higher than supply pressure is required to open the port when there is a positive pressure on the supply side. An integral strainer at the inlet ensures debris does not foul the device’s check valves or enter the carbonator unit.

Effective Opening:
The minimum cross-sectional area at the point of water supply discharge, measured or expressed in terms of the diameter of a circle or, if the opening is not circular, the diameter of a circle of equivalent cross-sectional area.

Flood Level Rim:
That level from which liquid in plumbing fixtures, appliances or vats could overflow to the floor, when all drain and overflow openings built into the equipment are obstructed.

Breaker (HCDVB):
A vacuum breaker consisting of two independently acting check valves, forced loaded or biased to a normally closed position. Located between the checks is a means of venting to atmosphere that is forced loaded or biased to a normally open position. If there
is no flow through the device, the check valves are closed and the vent is open. The HCDVB is designed to be used, under pressure , only when water is being drawn  from the system and for short, intermittent periods of time.

Effective Opening:
The minimum cross-sectional area at the point of water supply discharge, measured or expressed in terms of the diameter of a circle, or if the opening is not circular, the diameter of a circle of equivalent cross-sectional area.

Flood Level Rim:
That level from Which liquid in plumbing fixtures, appliances or vats could overflow to the floor, when all drain and overflow openings built into the equipment are obstructed.

Hose Connection Vacuum Breaker (HCVB):
An HCVB is a device consisting of a force loaded check valve biased to the normally closed position and an atmospheric vent or means, that is force loaded or biased to the normally open position.

Internal Isolation:
Internal isolation consists of fixture isolation and/or isolation of an Area or Zone. Isolation at the fixture is installing an approved backflow preventer at the source of the potential contamination. Area or Zone isolation is confining the potential source of contamination within a specific area.

Lab Faucet Vacuum Breaker (LFVB):
A LFVB is a device consisting of two independently acting check valves force loaded or biased to the normally closed position, between the check valves there is a means of automatically venting to  atmosphere that is force loaded or biased to the normally open position.

Participating Section:
For the purposes of this manual a “Participating Canadian Section of AWWA” is defined as one that has qualified, under any applicable rules, to have voting members serve on the Canadian AWWA Cross Connection Control Steering Committee.

Pollution:
The presence of any foreign substance in water that tends to degrade it’s quality so as to constitute a hazard or impair the usefulness of the water.

Potable Water:
Water which is safe for human consumption, as described by the Public Health authority having jurisdiction.

Premise Isolation:
Preventing backflow into a public water system from a user’s premises by installing a suitable backflow preventer at the user’s connection.

Pressure Vacuum Breaker Assembly (PVB):
An assembly consisting of an internally loaded check valve(sometimes two), an internally loaded vacuum relief valve(for the downstream side), inlet and outlet shutoff valves, and test cocks, designed to operate under pressure for prolonged periods of time to prevent backsiphonage.

Readily Assessable:
Capable of being reached for operation, renewal, servicing, or inspection, without requiring the climbing over or removal of an obstacle or the use of a portable ladder.

Reduced Pressure Principle Backflow Prevention Assembly (RP):
An Assembly consisting of two independently acting, internally loaded, approved check valves separated by a reduced pressure zone having an approved pressure differential relief valve. This backflow preventer is installed as a unit between two tightly closing shut off valves and having suitable connections for testing the watertightness of each check valve, and the operation of the operation of the pressure differential relief valve.

Service Connection:
A piping connection between the water purveyor’s main and a user’s systems.

Shutoff Valves:
The shutoff valves called for on backflow prevention assemblies shall be resilient seated shutoff valves(ie. Full port ball valves, resilient wedged gate valves, etc.) and shall have full flow characteristics.

Single Check Valve (non approved backflow preventer):
A single, soft seated check valve, which may or may not be internally loaded and shall have suitable connections for testing the watertightness of the check valve.

Spill Resistant Type Pressure Vacuum Breaker(SRPVB):
An assembly containing an independently acting check valve force-loaded or biased to a normal closed position, and an independently  operation air inlet valve force-loaded  or biases to a normally opened position and located on the discharge side of the check valve. A diaphragm separates the flow from the air inlet.
The assembly is equipped with properly located resilient-seated test cock (bleeder) and tightly closing resilient –seated shut off valves located at each end of the assembly.

Test Cocks:
The test cocks called for an backflow prevention assemblies shall be resilient seated test cocks(ie. Full port ball valves, full port plug valves, full port needle valves, etc.) and shall have full flow characteristics.

Water Purveyors:
The owner or operator of a public potable water works system.

Zone Protection:
Protection provided for sections of a piping system within a building or facility with no potable connections downstream of a backflow preventer.

Definitions
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