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ASSE 5130 practice questions

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Question 1Cross-Connection Control Fundamentals and Regulations

What is the primary purpose of a cross-connection control program?

  1. To prevent contaminants and pollutants from entering the potable water supply Correct answer.
  2. To increase water pressure in the distribution system
  3. To reduce the cost of water treatment chemicals
  4. To monitor water usage for billing purposes

Explanation

A cross-connection control program is designed to protect public health by preventing the backflow of contaminants or pollutants into the drinking water supply. This is achieved through identification and elimination of cross-connections, and installation of appropriate backflow prevention assemblies.

Question 2Cross-Connection Control Fundamentals and Regulations

Which of the following is considered a cross-connection?

  1. A pressure reducing valve on a boiler feed line
  2. A direct connection between a potable water line and a drain line Correct answer.
  3. A backflow preventer installed at a fire sprinkler system
  4. A water meter installed on a service line

Explanation

A cross-connection is any actual or potential connection between a potable water system and any source of contamination or pollution. A direct connection to a drain line creates a path for backflow, making it a cross-connection.

Question 3Cross-Connection Control Fundamentals and Regulations

What is backflow?

  1. The reverse flow of water or other substances into the potable water system Correct answer.
  2. The normal forward flow of water from the treatment plant to the customer
  3. The accumulation of sediment in a water heater
  4. The loss of water pressure due to a pipe break

Explanation

Backflow is the undesirable reversal of flow of water or mixtures of water and other substances into the distribution pipes of the potable supply. It can be caused by backsiphonage or backpressure.

Question 4Cross-Connection Control Fundamentals and Regulations

Which condition can cause backsiphonage?

  1. A negative pressure in the supply piping Correct answer.
  2. A closed valve on a branch line
  3. An increase in supply pressure above atmospheric
  4. A booster pump adding pressure to the system

Explanation

Backsiphonage occurs when there is a negative or sub-atmospheric pressure in the supply piping, which can draw nonpotable liquids into the potable system through a cross-connection. This can happen during a main break, firefighting, or other high-demand events.

Question 5Cross-Connection Control Fundamentals and Regulations

What is the primary difference between a pollutant and a contaminant?

  1. A pollutant is found only in wastewater; a contaminant is found only in stormwater
  2. A pollutant is always toxic; a contaminant is never harmful
  3. A pollutant affects the color, odor, or taste but not health; a contaminant may cause illness Correct answer.
  4. A pollutant is a gas; a contaminant is a liquid

Explanation

In cross-connection control, a pollutant is a substance that degrades the aesthetic quality of water (taste, odor, color) but does not pose a health hazard. A contaminant is a substance that can cause illness or disease if ingested.

Question 6Cross-Connection Control Fundamentals and Regulations

Which agency is responsible for enforcing the Safe Drinking Water Act (SDWA) at the federal level in the United States?

  1. The Environmental Protection Agency (EPA) Correct answer.
  2. The Food and Drug Administration (FDA)
  3. The Department of Housing and Urban Development (HUD)
  4. The Occupational Safety and Health Administration (OSHA)

Explanation

The EPA is the federal agency responsible for administering and enforcing the Safe Drinking Water Act. It sets national drinking water standards and oversees state implementation.

Question 7Cross-Connection Control Fundamentals and Regulations

What is an air gap?

  1. A device that uses two check valves to prevent backflow
  2. A reduced pressure zone assembly with a relief valve
  3. A physical separation between the free-flowing discharge end of a potable water pipe and an open or non-pressure-receiving vessel Correct answer.
  4. A vacuum breaker installed on a hose bibb

Explanation

An air gap is the unobstructed vertical distance through the free atmosphere between the lowest opening of a potable water outlet and the flood level rim of a receptacle. It is the most effective backflow prevention method.

Question 8Cross-Connection Control Fundamentals and Regulations

Which type of backflow preventer is suitable for protection against both backsiphonage and backpressure?

  1. Atmospheric vacuum breaker
  2. Pressure vacuum breaker
  3. Reduced pressure principle assembly Correct answer.
  4. Double check valve assembly

Explanation

A reduced pressure principle assembly (RPZ) is designed to protect against both backsiphonage and backpressure. It contains two independently acting check valves and a differential pressure relief valve.

Question 9Cross-Connection Control Fundamentals and Regulations

What is the minimum required air gap for a potable water outlet with a 1-inch effective opening?

  1. Three times the effective opening diameter
  2. Two times the effective opening diameter Correct answer.
  3. One times the effective opening diameter
  4. Four times the effective opening diameter

Explanation

The minimum air gap for a potable water outlet is twice the effective opening diameter, unless a greater distance is required by local code. For a 1-inch opening, the minimum air gap is 2 inches.

Question 10Cross-Connection Control Fundamentals and Regulations

A hose bibb with a threaded outlet is used to fill a swimming pool. Which backflow prevention method is appropriate?

  1. A reduced pressure principle assembly
  2. A hose bibb vacuum breaker Correct answer.
  3. A pressure vacuum breaker
  4. A double check valve assembly

Explanation

A hose bibb vacuum breaker is a simple, inexpensive device that can be attached to a threaded hose bibb to prevent backsiphonage. It is suitable for low-hazard, intermittent use such as filling a pool.

Question 11Cross-Connection Control Fundamentals and Regulations

What is the primary hazard associated with a boiler feed line cross-connection?

  1. Reduction of boiler efficiency
  2. Backflow of boiler water containing chemicals into the potable supply Correct answer.
  3. Scale buildup in the potable water lines
  4. Excessive pressure causing pipe erosion

Explanation

Boiler feed lines often contain chemicals such as corrosion inhibitors and antifoaming agents. If a cross-connection exists, backflow can contaminate the potable water supply with these hazardous substances.

Question 12Cross-Connection Control Fundamentals and Regulations

Which backflow prevention device is typically required for a lawn irrigation system with pop-up sprinklers?

  1. A hose bibb vacuum breaker
  2. A double check valve assembly
  3. An atmospheric vacuum breaker
  4. A pressure vacuum breaker or reduced pressure principle assembly Correct answer.

Explanation

Irrigation systems with pop-up sprinklers are considered a high hazard because they can be exposed to fertilizers, pesticides, and animal waste. A pressure vacuum breaker or reduced pressure principle assembly provides the necessary protection against backsiphonage and backpressure.

Question 13Cross-Connection Control Fundamentals and Regulations

What is the purpose of a reduced pressure principle assembly's relief valve?

  1. To prevent water from flowing backward through the first check valve
  2. To discharge water if the pressure differential between the two check valves becomes too low Correct answer.
  3. To regulate the downstream pressure to a set point
  4. To allow air into the system to break a vacuum

Explanation

The relief valve in an RPZ assembly opens when the pressure in the zone between the two check valves drops below a certain threshold, typically 2 psi. This discharges water and prevents backflow from reaching the potable supply.

Question 14Cross-Connection Control Fundamentals and Regulations

How often should a reduced pressure principle assembly be tested?

  1. Only when installed
  2. Every five years
  3. Every month
  4. At least annually Correct answer.

Explanation

Most regulations require that reduced pressure principle assemblies be tested at least annually by a certified tester to ensure they are functioning properly. Some jurisdictions may require more frequent testing.

Question 15Cross-Connection Control Fundamentals and Regulations

What is the role of a certified backflow prevention assembly tester?

  1. To install backflow prevention assemblies
  2. To enforce plumbing codes
  3. To test and maintain backflow prevention assemblies to ensure they are functioning correctly Correct answer.
  4. To design water distribution systems

Explanation

A certified tester is responsible for testing backflow prevention assemblies using approved procedures and equipment, and for reporting the results to the water authority. They may also perform maintenance and repairs if certified.

Question 16Cross-Connection Control Fundamentals and Regulations

Which of the following is a common cause of backpressure?

  1. A fire hydrant opened for flushing
  2. A broken water main
  3. A booster pump in a building's water system Correct answer.
  4. A sudden drop in system pressure

Explanation

Backpressure occurs when the pressure downstream of a cross-connection exceeds the supply pressure, often due to a pump, elevated tank, or thermal expansion. A booster pump can create such a pressure differential.

Question 17Cross-Connection Control Fundamentals and Regulations

What is the required air gap for a toilet tank fill valve?

  1. No air gap is required
  2. At least 6 inches
  3. At least 1 inch or twice the effective opening, whichever is greater Correct answer.
  4. At least 1/4 inch

Explanation

Toilet tank fill valves must have an air gap of at least 1 inch or twice the effective opening of the outlet, whichever is greater, to prevent backsiphonage of tank water into the potable supply. This is typically achieved by the design of the fill valve.

Question 18Cross-Connection Control Fundamentals and Regulations

Which type of backflow preventer is best suited for a carbonated beverage dispenser?

  1. A double check valve assembly
  2. A reduced pressure principle assembly Correct answer.
  3. A pressure vacuum breaker
  4. An atmospheric vacuum breaker

Explanation

Carbonated beverage dispensers pose a high hazard due to the potential for backflow of syrup and carbon dioxide. A reduced pressure principle assembly provides the highest level of protection against both backsiphonage and backpressure.

Question 19Cross-Connection Control Fundamentals and Regulations

What is the primary responsibility of the water purveyor in a cross-connection control program?

  1. To design plumbing systems for new buildings
  2. To test backflow prevention assemblies annually
  3. To install backflow prevention assemblies on all customer premises
  4. To protect the public water system from contamination and to enforce cross-connection regulations Correct answer.

Explanation

The water purveyor is responsible for protecting the public water system from contamination, which includes implementing and enforcing a cross-connection control program. This may involve inspections, record-keeping, and requiring installation of backflow prevention assemblies.

Question 20Cross-Connection Control Fundamentals and Regulations

Which of the following is an example of a point-of-use backflow prevention device?

  1. A pressure vacuum breaker on an irrigation main
  2. A reduced pressure principle assembly at the water meter
  3. A hose bibb vacuum breaker Correct answer.
  4. A double check valve assembly on a fire line

Explanation

A point-of-use device protects a specific fixture or appliance, such as a hose bibb vacuum breaker attached to a single faucet. The other options are typically installed at the service entrance or on a specific system, not at the point of use.

Question 21Cross-Connection Control Fundamentals and Regulations

What is the purpose of a thermal expansion tank in a backflow prevention system?

  1. To absorb increased pressure caused by thermal expansion of water Correct answer.
  2. To prevent backflow through a reduced pressure principle assembly
  3. To provide a reserve of water for firefighting
  4. To filter out contaminants from the water supply

Explanation

When a backflow preventer is installed, it creates a closed system. A thermal expansion tank provides a space for water to expand as it heats, preventing excessive pressure buildup that could damage the system or cause the relief valve to discharge.

Question 22Cross-Connection Control Fundamentals and Regulations

A reduced pressure principle assembly is installed on a fire sprinkler system. What is a potential issue if the assembly is not properly drained?

  1. The fire sprinkler system will lose pressure
  2. The assembly will not be able to be tested
  3. The assembly will allow backflow to occur
  4. The relief valve may discharge water continuously due to freezing Correct answer.

Explanation

If an RPZ assembly is not properly drained, water can freeze in the relief valve or sensing lines, causing the relief valve to stick open or discharge continuously. This can lead to water damage and inaccurate testing results.

Question 23Cross-Connection Control Fundamentals and Regulations

In a cross-connection control program, what is the purpose of a hazard assessment?

  1. To determine the water bill for each customer
  2. To design the layout of a new water treatment plant
  3. To evaluate the potential risk of contamination to the water system from various cross-connections Correct answer.
  4. To schedule regular maintenance of the distribution system

Explanation

A hazard assessment identifies and evaluates the degree of hazard posed by cross-connections in a water system. This helps prioritize which connections require protection and what type of backflow prevention is needed.

Question 24Cross-Connection Control Fundamentals and Regulations

Which of the following best describes the concept of containment versus isolation in cross-connection control?

  1. Containment protects the public water system at the service connection; isolation protects individual fixtures or systems within a building Correct answer.
  2. Containment is used only for fire systems; isolation is used only for irrigation
  3. Containment and isolation are the same thing
  4. Containment protects individual fixtures; isolation protects the public water system

Explanation

Containment is the practice of protecting the public water system from contamination originating within a customer's premises by installing a backflow preventer at the service connection. Isolation protects specific fixtures or systems within the premises.

Question 25Cross-Connection Control Fundamentals and Regulations

A water utility is considering requiring backflow prevention for all commercial customers. What factors should be considered in this decision?

  1. The number of customers in the service area
  2. The degree of hazard, cost of installation and testing, and available enforcement resources Correct answer.
  3. Only the cost of the backflow prevention assemblies
  4. The age of the distribution system

Explanation

A comprehensive approach considers the hazard level of each connection, the financial impact on customers, and the utility's ability to enforce and maintain the program. This ensures resources are directed where they are most needed.

Question 26Cross-Connection Control Fundamentals and Regulations

Which term describes the reversal of normal flow direction in a potable water piping system caused by a drop in supply pressure below the pressure on the downstream side?

  1. Recirculation
  2. Backsiphonage Correct answer.
  3. Backpressure
  4. Cross-connection

Explanation

Backsiphonage occurs when a negative or sub-atmospheric pressure develops in the supply piping and draws nonpotable material into the potable system. It is distinguished from backpressure, which involves downstream pressure exceeding supply pressure. Both are forms of backflow that cross-connection control programs must prevent.

Question 27Cross-Connection Control Fundamentals and Regulations

Under the federal Safe Drinking Water Act, which entity holds the primary responsibility for ensuring that public water systems meet drinking water standards?

  1. The local plumbing inspector
  2. The property owner
  3. The state primacy agency Correct answer.
  4. The certified backflow tester

Explanation

The Safe Drinking Water Act allows states to assume primary enforcement responsibility, known as primacy, for public water systems within their borders. The state primacy agency adopts and enforces regulations at least as stringent as federal requirements. Local inspectors and testers support compliance but do not hold primacy authority.

Question 28Cross-Connection Control Fundamentals and Regulations

A chemical storage tank is connected to a potable water line through a fill pipe that terminates below the tank's overflow rim. Which protection method is most appropriate for this high-hazard, backpressure-prone connection?

  1. A vacuum breaker
  2. A barometric loop
  3. A reduced pressure principle assembly Correct answer.
  4. A dual check valve

Explanation

A reduced pressure principle assembly protects against both backsiphonage and backpressure and provides the high level of protection required for a high-hazard chemical connection. Its relief valve discharges if either check valve fails. Devices such as dual checks or vacuum breakers offer lesser protection and do not suit this hazard.

Question 29Cross-Connection Control Fundamentals and Regulations

An inspector finds a submerged inlet in a janitorial sink used to fill mop buckets. Which condition does this create, and what does it require?

  1. A backpressure condition, because the sink is above the floor
  2. A cross-connection, because a potable outlet is submerged in a nonpotable liquid Correct answer.
  3. An air gap, because the sink is a fixture
  4. A water hammer condition, because the inlet is restricted

Explanation

A potable water outlet that terminates below the flood level rim of a fixture containing nonpotable water forms a cross-connection. Submerged inlets can allow contaminants to be drawn into the potable supply during backsiphonage. The condition calls for correction through an air gap or an approved backflow prevention device.

Question 30Cross-Connection Control Fundamentals and Regulations

A water purveyor must classify a new industrial customer's service as either a containment or an isolation scenario. Which statement best reflects the containment principle?

  1. Protection is placed at the service connection to shield the public main from the entire premises Correct answer.
  2. Each fixture is individually protected within the building
  3. Protection is limited to the irrigation system
  4. Only high-hazard fixtures are protected at the point of use

Explanation

Containment places a backflow prevention assembly at the service connection so the public water main is shielded from any hazard originating on the premises. Isolation, by contrast, protects individual fixtures or branches inside the building. Many programs require containment as a baseline while using isolation for internal hazards.

Question 31Backflow Prevention Assembly Types and Applications

Which backflow prevention assembly is designed so that the relief valve opens to discharge water when the pressure differential across the first check falls below a set value?

  1. Double check valve assembly
  2. Pressure vacuum breaker assembly
  3. Atmospheric vacuum breaker
  4. Reduced pressure principle assembly Correct answer.

Explanation

A reduced pressure principle assembly uses a spring-loaded differential relief valve located between two independently acting check valves. When supply pressure drops enough that the differential across the first check is lost, the relief valve opens and dumps water to atmosphere, protecting the potable line. This makes it suitable for high-hazard applications.

Question 32Backflow Prevention Assembly Types and Applications

A backflow assembly is installed to protect a potable water line feeding a chemical mixing station where a toxic substance is present. Which assembly provides the required level of protection?

  1. Atmospheric vacuum breaker
  2. Hose connection vacuum breaker
  3. Double check valve assembly
  4. Reduced pressure principle assembly Correct answer.

Explanation

Toxic or health-hazard cross connections require the highest degree of protection, which is a reduced pressure principle assembly. It protects against both backsiphonage and backpressure conditions. Devices such as double checks and vacuum breakers do not provide the same level of protection for toxic hazards.

Question 33Backflow Prevention Assembly Types and Applications

Which assembly is a testable device consisting of two independently acting check valves with no relief valve?

  1. Reduced pressure principle assembly
  2. Pressure vacuum breaker assembly
  3. Spill-resistant vacuum breaker
  4. Double check valve assembly Correct answer.

Explanation

A double check valve assembly contains two independently acting check valves in series and has no relief valve. It is testable and is approved for low-hazard cross connections. Because it cannot discharge water, it offers less protection than a reduced pressure principle assembly.

Question 34Backflow Prevention Assembly Types and Applications

Where must a pressure vacuum breaker assembly be installed relative to the highest downstream piping or outlet?

  1. At least 6 inches below the highest downstream outlet
  2. At or below the highest downstream outlet
  3. Level with the lowest downstream fixture
  4. At least 12 inches above the highest downstream outlet Correct answer.

Explanation

A pressure vacuum breaker must be installed at least 12 inches above the highest point of downstream piping or the highest outlet it protects. This elevation prevents the air inlet from being submerged and allows the device to vent on loss of supply pressure. Failure to maintain the height defeats its backsiphonage protection.

Question 35Backflow Prevention Assembly Types and Applications

Which device is a non-testable, non-removable unit typically installed on a hose bibb to prevent backsiphonage?

  1. Reduced pressure principle assembly
  2. Hose connection vacuum breaker Correct answer.
  3. Pressure vacuum breaker assembly
  4. Double check valve assembly

Explanation

A hose connection vacuum breaker is a small, non-testable device threaded onto a hose bibb to prevent backsiphonage through the hose. It is not intended for continuous pressure or backpressure conditions. Larger testable assemblies serve different applications.

Question 36Backflow Prevention Assembly Types and Applications

Which principle describes backflow caused when the supply pressure drops below the pressure on the downstream side of a cross connection?

  1. Backsiphonage Correct answer.
  2. Water hammer
  3. Backpressure
  4. Cavitation

Explanation

Backsiphonage occurs when supply pressure falls, creating a partial vacuum that draws contaminated water into the potable system. It is caused by negative or reduced pressure on the supply side. Backpressure, by contrast, results from downstream pressure exceeding supply pressure.

Question 37Backflow Prevention Assembly Types and Applications

A reduced pressure principle assembly must be installed with the relief valve oriented in which manner?

  1. At any orientation without restriction
  2. Vertical with the relief port facing upward
  3. Inverted so the relief port faces down into a drain
  4. Horizontal and free to discharge to atmosphere Correct answer.

Explanation

A reduced pressure principle assembly must be installed horizontally with the relief valve free to discharge to atmosphere. The relief port must never be submerged, plugged, or piped directly into a drain in a way that prevents discharge. Proper orientation ensures the device can relieve water when the differential is lost.

Question 38Backflow Prevention Assembly Types and Applications

Which assembly is appropriate for protection against both backsiphonage and backpressure in a high-hazard application?

  1. Double check valve assembly
  2. Atmospheric vacuum breaker
  3. Pressure vacuum breaker assembly
  4. Reduced pressure principle assembly Correct answer.

Explanation

Only a reduced pressure principle assembly provides protection against both backsiphonage and backpressure in high-hazard situations. It uses two checks plus a differential relief valve. Vacuum breakers protect against backsiphonage only, and double checks are limited to low hazards.

Question 39Backflow Prevention Assembly Types and Applications

What is the primary function of the air inlet on a pressure vacuum breaker assembly?

  1. To test the check valve for leakage
  2. To discharge contaminated water to the ground
  3. To admit air and break a vacuum when supply pressure drops Correct answer.
  4. To regulate downstream flow rate

Explanation

The air inlet on a pressure vacuum breaker opens when supply pressure drops, admitting air to break the vacuum and prevent backsiphonage. It does not discharge water as a relief valve would. This venting action is what protects the potable supply during pressure loss.

Question 40Backflow Prevention Assembly Types and Applications

A double check valve assembly is best suited for which type of cross connection?

  1. A toxic chemical connection under continuous pressure
  2. A submerged inlet below the flood level rim
  3. A hose bibb subject to backsiphonage
  4. A low-hazard connection where backpressure is possible Correct answer.

Explanation

A double check valve assembly is approved for low-hazard cross connections and can protect against both backsiphonage and backpressure. It is not acceptable for toxic or health-hazard situations. High-hazard or submerged conditions require a higher level of protection.

Question 41Backflow Prevention Assembly Types and Applications

Which condition would render a reduced pressure principle assembly's protection ineffective?

  1. The relief valve discharge port is plugged or submerged Correct answer.
  2. The assembly is tested annually
  3. The assembly has two independent check valves
  4. The assembly is installed horizontally

Explanation

If the relief valve discharge port is plugged or submerged, the assembly cannot relieve water when the differential is lost, defeating its protection. The port must remain open to atmosphere at all times. Horizontal installation and annual testing are correct practices, not defects.

Question 42Backflow Prevention Assembly Types and Applications

An atmospheric vacuum breaker must not be installed in which situation?

  1. Downstream of a valve that creates continuous pressure Correct answer.
  2. On a line that is open to atmosphere at the outlet
  3. Above the highest downstream outlet
  4. Where backsiphonage protection is needed

Explanation

An atmospheric vacuum breaker must not be subjected to continuous pressure, such as downstream of a shutoff valve, because the air inlet may be held closed and fail to vent. It relies on the absence of downstream pressure to open its air inlet. Continuous pressure requires a pressure vacuum breaker or other assembly.

Question 43Backflow Prevention Assembly Types and Applications

Which testable assembly contains a single check valve and an air inlet that opens at atmospheric pressure?

  1. Pressure vacuum breaker assembly Correct answer.
  2. Reduced pressure principle assembly
  3. Dual check valve
  4. Double check valve assembly

Explanation

A pressure vacuum breaker assembly has one check valve and an air inlet that opens when pressure drops to atmospheric, breaking the vacuum. It is testable and is used for backsiphonage protection. It differs from a double check, which has two checks and no air inlet.

Question 44Backflow Prevention Assembly Types and Applications

Why is a spill-resistant vacuum breaker preferred over an atmospheric vacuum breaker in some installations?

  1. It can be used under continuous pressure without spilling Correct answer.
  2. It eliminates the need for elevation above the outlet
  3. It provides protection against backpressure
  4. It is a testable assembly with a relief valve

Explanation

A spill-resistant vacuum breaker is designed to operate under continuous pressure and discharges only minimal water when it vents. This allows it to be used where an atmospheric vacuum breaker would be unsuitable. It still protects primarily against backsiphonage and is not a substitute for a reduced pressure assembly.

Question 45Backflow Prevention Assembly Types and Applications

A facility has a boiler feed line where downstream pressure can exceed the potable supply pressure. Which assembly is required for this high-hazard backpressure condition?

  1. Atmospheric vacuum breaker
  2. Reduced pressure principle assembly Correct answer.
  3. Hose connection vacuum breaker
  4. Pressure vacuum breaker assembly

Explanation

Backpressure combined with a high hazard requires a reduced pressure principle assembly, which protects against both backpressure and backsiphonage. Vacuum breakers are limited to backsiphonage protection and cannot be used under backpressure. The relief valve feature is essential for this condition.

Question 46Backflow Prevention Assembly Types and Applications

What does the term "spill-resistant" indicate about a vacuum breaker's discharge behavior?

  1. It discharges only when backpressure occurs
  2. It discharges continuously during normal flow
  3. It never discharges any water under any condition
  4. It discharges only a small amount of water when the air inlet opens Correct answer.

Explanation

A spill-resistant vacuum breaker is designed so that only a minimal amount of water spills from the air inlet when it opens. This reduces the nuisance and hazard of water discharge compared with a standard atmospheric vacuum breaker. It is still a backsiphonage protection device.

Question 47Backflow Prevention Assembly Types and Applications

A cross connection exists where a submerged inlet is below the flood level rim of a tank containing a non-toxic substance. Which is the minimum acceptable testable assembly?

  1. Atmospheric vacuum breaker
  2. Double check valve assembly Correct answer.
  3. Barometric loop
  4. Hose connection vacuum breaker

Explanation

For a low-hazard, non-toxic connection with a submerged inlet, a double check valve assembly provides testable protection against backsiphonage and backpressure. It is the minimum testable assembly acceptable for low hazards. Non-testable devices and barometric loops do not provide equivalent testable protection.

Question 48Backflow Prevention Assembly Types and Applications

Which statement correctly distinguishes a dual check valve from a double check valve assembly?

  1. The dual check is non-testable, while the double check assembly is testable Correct answer.
  2. The dual check has a relief valve, while the double check has none
  3. The dual check is approved for toxic hazards, while the double check is not
  4. The dual check protects against backpressure, while the double check does not

Explanation

A dual check valve is a non-testable device, whereas a double check valve assembly is a testable assembly with test cocks and shutoff valves. Both contain two check valves in series. The testability difference determines where each may be approved.

Question 49Backflow Prevention Assembly Types and Applications

During a field inspection, an atmospheric vacuum breaker is found installed downstream of a solenoid valve on a pressurized irrigation line. What is the primary concern?

  1. The device will provide excessive backpressure protection
  2. Continuous pressure may hold the air inlet closed, preventing proper venting Correct answer.
  3. The device will discharge water continuously during normal flow
  4. The device will fail because it is installed above the outlet

Explanation

An atmospheric vacuum breaker cannot be subjected to continuous pressure because the downstream valve can keep the air inlet from opening when supply pressure drops. This defeats its backsiphonage protection and may allow contamination to flow backward. A pressure vacuum breaker would be appropriate for that continuous-pressure location.

Question 50Backflow Prevention Assembly Types and Applications

A designer must protect a potable line serving a laboratory sink with a faucet-mounted aspirator that could be submerged in a toxic solution. Which assembly best satisfies the requirement?

  1. Dual check valve
  2. Atmospheric vacuum breaker
  3. Spill-resistant vacuum breaker
  4. Reduced pressure principle assembly Correct answer.

Explanation

A toxic solution with a potentially submerged aspirator creates a high-hazard cross connection requiring a reduced pressure principle assembly. It protects against both backsiphonage and backpressure and discharges to atmosphere when the differential is lost. Lower-level devices are insufficient for toxic hazards.