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ID Plumber practice questions

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Question 1General Plumbing Regulations, Definitions, and Administration

Under the Idaho plumbing licensing statute, which activity requires a state-issued journeyman plumber certificate?

  1. Hanging a mirror above a lavatory in a commercial restroom
  2. Replacing a bathroom vanity cabinet top with a pre-drilled sink
  3. Installing and repairing potable water piping and drainage systems for compensation Correct answer.
  4. Installing a plug-in dishwasher under an existing counter

Explanation

Plumbing work is defined by the installation, alteration, and repair of piping and fixtures that carry water, waste, or gas, and performing it for compensation requires certification under the state plumbing act. Cabinet tops, plug-in appliances, and mirrors involve no connection to a piping system.

Question 2General Plumbing Regulations, Definitions, and Administration

A plumbing contractor's qualifying journeyman leaves the company. What must the contractor do to remain in compliance with Idaho licensing rules?

  1. Notify the board and secure a replacement qualifier within the period the board allows Correct answer.
  2. Suspend all work permanently and surrender the license
  3. Continue operating indefinitely because the company license is already issued
  4. Transfer the license to the senior apprentice on the crew

Explanation

A contractor license is tied to an individual qualifier who is responsible for the work performed. When that person departs, the contractor must inform the board and obtain a new qualifier within the allowed timeframe or the license is affected. The license does not follow the company automatically without a qualified individual.

Question 3General Plumbing Regulations, Definitions, and Administration

Which document typically must be obtained before a plumbing contractor may legally begin work on a new commercial building?

  1. A plumbing permit issued by the local authority having jurisdiction Correct answer.
  2. A notarized letter from the water utility
  3. A certificate of occupancy for the building
  4. A copy of the manufacturer's installation instructions

Explanation

Local building and plumbing codes require a permit before regulated plumbing work begins, and the authority having jurisdiction issues it after reviewing the scope. Manufacturer instructions and utility letters may be needed for the job but do not authorize construction. A certificate of occupancy is issued after the work is complete and inspected.

Question 4General Plumbing Regulations, Definitions, and Administration

A homeowner wants to add a hose bibb to an existing exterior wall. Which statement best reflects how permit requirements usually apply?

  1. A permit is generally required because the work extends the potable water distribution system Correct answer.
  2. A permit is needed only if the bibb is frost-proof
  3. No permit is needed because the bibb is a minor fixture
  4. No permit is needed because the fixture is outdoors

Explanation

Adding a hose bibb creates a new branch of the potable water distribution system, which is regulated plumbing work and normally requires a permit and inspection. The location of the fixture outdoors does not remove it from code coverage. Whether the bibb is frost-proof affects materials, not permit applicability.

Question 5General Plumbing Regulations, Definitions, and Administration

In plumbing code terminology, what does the abbreviation "AHJ" refer to?

  1. The approved hardware joint standard
  2. The annual hydrant inspection program
  3. The authority having jurisdiction over code enforcement Correct answer.
  4. The American Hydronics Journal

Explanation

AHJ stands for authority having jurisdiction, the organization or official responsible for enforcing the code and approving materials, methods, and inspections. It is a governance term rather than a product or publication reference. Plumbers interact with the AHJ for permits, inspections, and variances.

Question 6General Plumbing Regulations, Definitions, and Administration

A code uses the term "approved" when describing materials. What does that term mean in this context?

  1. Tested once by the supplier before shipment
  2. Accepted by the authority having jurisdiction as meeting the applicable standard Correct answer.
  3. Listed by any manufacturer as a best-selling product
  4. Accepted by the installing contractor as suitable for the job

Explanation

In plumbing codes, approved means acceptable to the authority having jurisdiction, often based on listing by a recognized testing agency. Contractor preference or sales popularity does not establish code approval. The term is a regulatory determination, not a marketing claim.

Question 7General Plumbing Regulations, Definitions, and Administration

Which term describes the vertical distance a fixture drain may fall before the trap, measured along the developed length of the pipe?

  1. Trap seal
  2. Trap arm Correct answer.
  3. Fixture branch
  4. Developed length

Explanation

The trap arm is the pipe segment connecting a fixture trap to the drainage stack or branch, and codes limit its length to protect the trap seal from siphonage. The trap seal is the water depth in the trap, not the pipe itself. Developed length measures total pipe run along its centerline.

Question 8General Plumbing Regulations, Definitions, and Administration

A plumbing inspector issues a correction notice citing a code section. Which action best preserves the contractor's right to dispute the interpretation?

  1. Follow the local appeal procedure and request review within the stated time limit Correct answer.
  2. Ask the supply house to certify the installation
  3. Wait until the final inspection to raise the objection
  4. Ignore the notice and complete the installation as designed

Explanation

Codes and local ordinances establish an appeal process with deadlines for contesting an inspector's ruling, and using it preserves the contractor's rights. Ignoring a correction notice can lead to stop-work orders or penalties. Suppliers and final inspections are not substitutes for the formal appeal route.

Question 9General Plumbing Regulations, Definitions, and Administration

Which of the following best describes the role of a plumbing apprentice working under supervision?

  1. The apprentice may perform plumbing work only while supervised as the rules require Correct answer.
  2. The apprentice may sign off on completed inspections
  3. The apprentice may work alone once the first year is complete
  4. The apprentice may pull permits and contract directly with the owner

Explanation

Apprentices are in training and must work under the required supervision of a licensed journeyman or master plumber. They cannot contract for work, pull permits, or approve inspections. Supervision requirements continue throughout the apprenticeship, not just the first year.

Question 10General Plumbing Regulations, Definitions, and Administration

A master plumber wants to design a commercial grease interceptor installation. Which responsibility does the master plumber hold under typical state rules?

  1. Responsibility for code-compliant design and for the work performed under the license Correct answer.
  2. Responsibility only for scheduling the final inspection
  3. Responsibility only for collecting payment from the owner
  4. Responsibility only for ordering materials from the supplier

Explanation

A master plumber's license carries responsibility for the technical correctness of the design and installation performed under it. Payment, purchasing, and scheduling are administrative tasks that do not define the license holder's code obligations. The master remains accountable to the authority having jurisdiction for compliance.

Question 11General Plumbing Regulations, Definitions, and Administration

Which situation most clearly requires a plumbing permit even though the work is small in scale?

  1. Clearing a stoppage with a hand auger
  2. Replacing a section of a building drain beneath a slab Correct answer.
  3. Replacing a toilet tank lid
  4. Swapping a showerhead on an existing shower arm

Explanation

Cutting and replacing a portion of a building drain under a slab is alteration of the drainage system and requires a permit and inspection. Swapping a showerhead or tank lid changes no piping, and clearing a stoppage with a hand auger is maintenance. Small scale does not exempt work on concealed drain piping.

Question 12General Plumbing Regulations, Definitions, and Administration

An inspector finds that a contractor used a pipe material not listed in the code but approved by an engineer's sealed design. What is the most accurate statement about acceptance?

  1. The material is automatically rejected with no review possible
  2. The contractor may proceed because an engineer's seal overrides the code
  3. The authority having jurisdiction may accept it through the code's alternative-materials provision Correct answer.
  4. The supplier's warranty substitutes for code acceptance

Explanation

Most plumbing codes include an alternative-materials provision allowing the authority having jurisdiction to approve materials not specifically listed when evidence shows equivalent compliance. An engineer's seal supports the request but does not automatically override the code. Approval still rests with the authority.

Question 13General Plumbing Regulations, Definitions, and Administration

Which item is generally classified as a plumbing fixture under code definitions?

  1. A kitchen range hood
  2. An electrical water heater element
  3. A floor drain receptor that receives liquid waste Correct answer.
  4. A clothes dryer vent

Explanation

A floor drain receptor is a fixture that receives liquid waste and connects to the drainage system, placing it within the plumbing fixture definition. Range hoods and dryer vents handle air, and a heating element is an electrical component of an appliance rather than a fixture.

Question 14General Plumbing Regulations, Definitions, and Administration

A contractor begins work before the permit is issued but after submitting a complete application. How is this generally treated under plumbing administration rules?

  1. Work started before permit issuance is subject to enforcement action even if the application is pending Correct answer.
  2. The inspector must approve the work if it meets code
  3. The application date retroactively authorizes the earlier work
  4. The contractor is protected because the plans were already reviewed

Explanation

A permit is effective only when issued, so beginning work while an application is pending is unpermitted work and can draw stop-work orders, fees, or penalties. Submitting plans does not retroactively authorize construction. An inspector's approval of installed work does not cure the permit violation.

Question 15General Plumbing Regulations, Definitions, and Administration

Which record must a plumbing contractor typically make available to the authority having jurisdiction during an inspection?

  1. The supplier's price list
  2. The contractor's personal tax returns
  3. The approved permit and approved plans for the work being inspected Correct answer.
  4. The crew's payroll records

Explanation

Inspectors verify that the work matches the approved permit and plans, so those documents must be available on site. Financial records such as tax returns, price lists, and payroll are unrelated to code enforcement. Keeping the approved set on site is standard administrative practice.

Question 16General Plumbing Regulations, Definitions, and Administration

A municipality adopts a newer edition of the plumbing code with local amendments. Which version governs a plumbing permit application submitted after the effective date?

  1. The adopted edition with local amendments in effect on the application date Correct answer.
  2. The edition the contractor prefers for the project
  3. The previous edition because the design was drafted earlier
  4. The edition used by the supplier who stocked the materials

Explanation

The code in effect on the date the permit application is submitted governs the project, including any local amendments adopted with that edition. Drafting dates and personal preferences do not control which edition applies. Suppliers do not determine the governing code.

Question 17General Building and Plumbing Code Provisions

Under the International Residential Code, what is the minimum required size of a building sewer serving a one- or two-family dwelling?

  1. 3 inch diameter Correct answer.
  2. 6 inch diameter
  3. 4 inch diameter
  4. 2 inch diameter

Explanation

The IRC requires the building sewer for a one- or two-family dwelling to be not less than 3 inches in diameter. A 4-inch sewer is common practice but is not the minimum, and smaller sizes are permitted only for specific fixture drains, not the building sewer.

Question 18General Building and Plumbing Code Provisions

A water closet compartment in an accessible bathroom must comply with which minimum dimension for the compartment width?

  1. 44 inches
  2. 60 inches Correct answer.
  3. 36 inches
  4. 30 inches

Explanation

Accessible toilet compartments require a clear width of at least 60 inches to allow a wheelchair to enter and turn. The 36-inch figure applies to an accessible route, and 44 inches relates to an ambulatory compartment depth, not the standard compartment width.

Question 19General Building and Plumbing Code Provisions

What is the minimum size of a vent stack serving a residential drainage system under the IRC?

  1. 3 inch
  2. 1 1/2 inch
  3. 1 1/4 inch Correct answer.
  4. 2 inch

Explanation

The IRC permits a vent stack to be as small as 1 1/4 inches, though it must still be sized so the stack carries the required aggregate vent area. Individual fixture vents and stack vents are sized by fixture units, so the answer is a minimum, not a fixed size for every installation.

Question 20General Building and Plumbing Code Provisions

A horizontal drainage pipe is installed at a slope of 1/8 inch per foot. Which condition must be met for this slope to be permitted?

  1. The pipe must be cast iron
  2. The pipe must be a building drain outside the building
  3. The pipe must be at least 4 inches in diameter Correct answer.
  4. The pipe must serve only one fixture

Explanation

The plumbing code allows a slope of 1/8 inch per foot only for horizontal drainage pipes of 4-inch diameter or larger; smaller pipes require at least 1/4 inch per foot. The flatter slope is permitted because larger pipes maintain adequate velocity and scouring at lower gradients.

Question 21General Building and Plumbing Code Provisions

How many fixture units is a private residential bathtub rated at when sizing the drainage system?

  1. 3 fixture units
  2. 1 fixture unit
  3. 4 fixture units
  4. 2 fixture units Correct answer.

Explanation

A bathtub in a dwelling is assigned a drainage fixture unit value of 2. This value is used when adding up the total load on a building drain or sewer. Lavatories are typically 1 and water closets are typically 3, so the bathtub falls between them.

Question 22General Building and Plumbing Code Provisions

A trap for a fixture must be installed so that its vertical distance below the fixture outlet does not exceed what dimension, unless a closer connection is required by the fixture design?

  1. 36 inches
  2. 12 inches
  3. 24 inches Correct answer.
  4. 30 inches

Explanation

The vertical fall from the fixture outlet to the trap weir must not exceed 24 inches, because a longer drop allows excessive velocity and self-siphonage. Keeping the trap close to the fixture preserves the water seal.

Question 23General Building and Plumbing Code Provisions

What is the minimum required air gap for a fixture with an effective opening of 1 inch or less when installed to protect a potable water supply?

  1. Twice the diameter of the effective opening Correct answer.
  2. Equal to the diameter of the effective opening
  3. One-half the diameter of the effective opening
  4. Three times the diameter of the effective opening

Explanation

For an effective opening of 1 inch or less, the air gap must be at least twice the diameter of the effective opening, and never less than 1 inch. This separation prevents backflow by ensuring a physical break between the supply and the fixture.

Question 24General Building and Plumbing Code Provisions

A plumbing fixture is installed in a room that has no opening to the outside. What is the minimum required volume of the space before it can be classified as a confined space requiring combustion air provisions?

  1. 50 cubic feet per 1,000 Btu/h of input Correct answer.
  2. 25 cubic feet per 1,000 Btu/h of input
  3. 100 cubic feet per 1,000 Btu/h of input
  4. 75 cubic feet per 1,000 Btu/h of input

Explanation

A space is considered confined when its volume is less than 50 cubic feet per 1,000 Btu/h of the total input rating of appliances in that space. Below this threshold, the code requires outdoor or adjacent-space combustion air to be provided.

Question 25General Building and Plumbing Code Provisions

What is the minimum size of a cleanout opening for a drain serving a fixture with a 3-inch drain?

  1. 1 1/2 inches
  2. 2 inches
  3. Same diameter as the pipe Correct answer.
  4. One size smaller than the pipe

Explanation

Cleanouts must be the same nominal size as the pipe they serve, so a 3-inch drain requires a 3-inch cleanout. This ensures the cleaning tool can pass through the opening without restriction.

Question 26General Building and Plumbing Code Provisions

A building has a water service pipe installed at a depth that will not protect it from frost. What must the installer do to protect the service?

  1. Add a pressure-reducing valve
  2. Install a backwater valve
  3. Install the service with a means of freeze protection acceptable to the code official Correct answer.
  4. Increase the pipe diameter

Explanation

When the service cannot be buried below the frost line, the code requires an approved method of freeze protection, such as insulation, heat tracing, or another means accepted by the authority. Increasing diameter or adding valves does not prevent freezing.

Question 27General Building and Plumbing Code Provisions

What is the minimum required size of a vent serving a single lavatory in a residential bathroom?

  1. 1 1/2 inch
  2. 2 inch
  3. 2 1/2 inch
  4. 1 1/4 inch Correct answer.

Explanation

A single lavatory is permitted to be vented with a 1 1/4-inch vent pipe, consistent with the minimum vent size allowed for small fixtures. Larger vents are acceptable but not required for this single fixture.

Question 28General Building and Plumbing Code Provisions

A water heater is installed in a dwelling and must be provided with a temperature and pressure relief valve. Where must the discharge pipe from that valve terminate?

  1. Into the building sewer
  2. To a point that is observable and will not cause injury or damage Correct answer.
  3. Into the water heater drain pan
  4. At the floor drain inside the building

Explanation

The relief valve discharge must terminate in an observable location where discharge will not cause injury or property damage, typically outside or at an approved receptor. It must not be connected directly to the drainage system or hidden from view.

Question 29General Building and Plumbing Code Provisions

What is the minimum required diameter of a building drain for a single-family dwelling under the IRC?

  1. 3 inches Correct answer.
  2. 4 inches
  3. 2 inches
  4. 6 inches

Explanation

The building drain for a one- or two-family dwelling must be at least 3 inches in diameter. The same minimum applies to the building sewer. A 4-inch drain is common but is not the code minimum.

Question 30General Building and Plumbing Code Provisions

A horizontal wet vent is used to vent a bathroom group. Which condition must be satisfied for this arrangement to be permitted?

  1. The wet vent must connect to a dry vent at its downstream end Correct answer.
  2. The wet vent must serve fixtures in more than one bathroom
  3. The wet vent must be at least 4 inches in diameter
  4. The wet vent must be installed with a slope of 1/8 inch per foot

Explanation

A horizontal wet vent must connect to a dry vent at its downstream end so the vent path remains continuous to the stack or vent terminal. Without that connection, the wet vent would not function as a vent for the fixtures it serves.

Question 31General Building and Plumbing Code Provisions

What is the minimum required clearance between a water closet and a side wall in a residential bathroom?

  1. 18 inches
  2. 24 inches
  3. 12 inches
  4. 15 inches Correct answer.

Explanation

A water closet must be set at least 15 inches from any side wall or partition, measured from the centerline of the fixture. This clearance allows normal use and provides space for the user.

Question 32General Building and Plumbing Code Provisions

An indirect waste receptor receives discharge from a commercial dishwasher. What is the required air gap between the discharge pipe and the receptor rim?

  1. At least 4 inches
  2. At least 1 inch or twice the pipe diameter, whichever is greater Correct answer.
  3. At least one-half the pipe diameter
  4. At least the pipe diameter

Explanation

The air gap for an indirect waste must be at least 1 inch or twice the effective opening of the discharge pipe, whichever is greater. This prevents backflow from the receptor into the fixture or appliance.

Question 33General Building and Plumbing Code Provisions

A plumbing system is installed in a building and the code official requires a permit. Which of the following is generally required before work covered by the permit may be concealed?

  1. An inspection of the rough-in before concealment Correct answer.
  2. A water quality test
  3. A final inspection after concealment
  4. A certificate of occupancy

Explanation

Rough-in inspections must be completed and approved before piping is covered or concealed, so the inspector can verify materials, slope, and connections. Concealing work before inspection is a common code violation.

Question 34General Building and Plumbing Code Provisions

What is the minimum required size of a floor drain trap for a shower that is not part of a bathtub?

  1. 2 inch
  2. 3 inch
  3. 1 1/2 inch Correct answer.
  4. 1 1/4 inch

Explanation

A shower drain trap must be at least 1 1/2 inches in diameter, which matches the minimum drain size for a shower. Smaller traps would not handle the flow or provide an adequate seal.

Question 35General Building and Plumbing Code Provisions

A backwater valve is installed on a building drain. What is the primary purpose of this device?

  1. To prevent sewage from backing up into the building Correct answer.
  2. To regulate water pressure in the building
  3. To vent the drainage system
  4. To prevent sewer gas from entering the building

Explanation

A backwater valve is a one-way device that closes when flow reverses, preventing sewage from the public sewer from backing up into the building. It protects fixtures and the building from flooding during sewer surcharge conditions.

Question 36General Building and Plumbing Code Provisions

A vent terminal is installed on a roof. What is the minimum required distance from a window, door, or other opening into the building?

  1. 2 feet
  2. 10 feet Correct answer.
  3. 3 feet
  4. 4 feet

Explanation

A vent terminal must be at least 10 feet from a window, door, or other opening into the building, and it must be at least 2 feet above the roof surface and 10 feet from a lot line. The distance prevents sewer gas from entering occupied spaces.

Question 37Fixtures, Fixture Fittings, and Water Heaters

A plumbing code requires a minimum uniform pressure of 8 psi at the outlet of a flushometer valve serving a water closet. Which condition is the code addressing?

  1. The maximum pressure the valve can withstand
  2. The static pressure available at the fixture branch
  3. The residual pressure needed for the valve to function Correct answer.
  4. The pressure rating of the fixture supply stop

Explanation

Flushometer valves are flow-pressure devices that need a defined flowing (residual) pressure at the valve outlet to deliver a proper flush volume. Static pressure measured with no flow does not guarantee that the valve will operate correctly when it opens.

Question 38Fixtures, Fixture Fittings, and Water Heaters

A storage-type electric water heater is installed in a dwelling unit. Which fitting is required on the cold water inlet to protect against backflow caused by thermal expansion?

  1. A vacuum relief valve
  2. A check valve only
  3. A thermal expansion tank or an approved means of relieving expansion pressure Correct answer.
  4. A temperature and pressure relief valve

Explanation

When a check valve or other backflow preventer isolates the heater from the public main, heated water expansion has nowhere to go and pressure rises. A thermal expansion tank or another approved method must absorb or relieve that expansion.

Question 39Fixtures, Fixture Fittings, and Water Heaters

What is the principal purpose of the temperature and pressure relief valve on a water heater?

  1. To prevent backflow into the cold water main
  2. To relieve excessive temperature or pressure before the tank fails Correct answer.
  3. To limit the tank temperature to the thermostat setpoint
  4. To drain the tank for servicing

Explanation

The T&P relief valve is a safety device that opens when tank temperature or pressure exceeds its rating, preventing a rupture. Its discharge must be piped to a safe location.

Question 40Fixtures, Fixture Fittings, and Water Heaters

A water closet has a flush valve (flushometer) rather than a tank. Which fixture supply characteristic is most important for it to flush properly?

  1. A long, restricted supply line to dampen surge
  2. A large-diameter supply with adequate residual pressure at the valve Correct answer.
  3. A small-diameter supply with high static pressure
  4. A supply fitted with a flow restrictor

Explanation

Flushometer valves open fully and depend on a high flow rate at sufficient residual pressure to complete the flush. Undersized piping or excessive pressure loss causes weak, incomplete flushes.

Question 41Fixtures, Fixture Fittings, and Water Heaters

Which fixture is required to be installed with a water closet compartment that has a door swinging outward or a door that is not required?

  1. A water closet in an accessible toilet room Correct answer.
  2. A bathtub
  3. A drinking fountain
  4. A lavatory

Explanation

Accessibility requirements call for toilet compartments in accessible toilet rooms to allow a wheelchair user to enter and transfer. An outward-swinging door, or a layout where the door is not required, preserves the clear floor space inside.

Question 42Fixtures, Fixture Fittings, and Water Heaters

A lavatory drain is connected to the drainage system with a 1-1/4 inch trap arm that runs 30 inches horizontally before it vents. Assuming the trap arm slope is correct, which condition determines whether this installation is acceptable?

  1. The trap arm length must not exceed the developed length allowed for its diameter Correct answer.
  2. The trap arm must be vertical for its entire length
  3. The trap arm must be larger than the drain it serves
  4. The trap arm must be at least 36 inches long

Explanation

Each trap arm has a maximum developed length based on its diameter, because a longer arm risks the trap siphoning before the vent can protect it. A 1-1/4 inch trap arm has a limited allowable length that must be verified against the code table.

Question 43Fixtures, Fixture Fittings, and Water Heaters

A fixture has an indirect waste connection discharging into a floor sink. What is the required minimum air gap between the indirect waste pipe outlet and the flood level rim of the receptor?

  1. Twice the pipe diameter
  2. One-half inch regardless of pipe size
  3. One pipe diameter
  4. One inch or twice the pipe diameter, whichever is greater Correct answer.

Explanation

An indirect waste receptor must provide an air gap equal to at least one inch or twice the diameter of the indirect waste pipe, whichever is greater. This prevents backflow from the receptor into the fixture.

Question 44Fixtures, Fixture Fittings, and Water Heaters

A 40-gallon electric water heater is replaced with a 50-gallon unit in a dwelling. Which element of the installation is most likely to require adjustment to remain compliant?

  1. The seismic strapping height and the T&P relief valve rating relative to the new tank Correct answer.
  2. The cold water inlet dip tube length only
  3. The drain pan diameter only
  4. The relief valve discharge termination point

Explanation

A larger tank changes the relief valve rating required and may change strapping requirements based on tank dimensions and weight. The installer must confirm the T&P valve matches the new tank's rating and that restraints comply.

Question 45Fixtures, Fixture Fittings, and Water Heaters

A plumber is installing a water heater in a garage. Which requirement most directly protects against ignition of gasoline vapors?

  1. The heater must be elevated so the ignition source is at least 18 inches above the floor Correct answer.
  2. The heater must be wrapped in insulation
  3. The heater must be piped with a thermal expansion tank
  4. The heater must be installed with a vacuum relief valve

Explanation

Gasoline vapors are heavier than air and collect near the floor. Elevating the ignition source, typically at least 18 inches above the floor for appliances in garages, reduces the risk of igniting those vapors.

Question 46Fixtures, Fixture Fittings, and Water Heaters

A shower is fitted with a pressure-balancing mixing valve. Which condition does this valve primarily guard against?

  1. Excessive flow rate through the showerhead
  2. Backflow of shower water into the cold water line
  3. A sudden change in hot or cold water pressure causing a temperature swing Correct answer.
  4. Scale buildup in the showerhead

Explanation

A pressure-balancing valve senses changes in hot and cold supply pressures and shifts the mix to keep the outlet temperature stable. This prevents a sudden scalding or chilling surge when another fixture is used.

Question 47Fixtures, Fixture Fittings, and Water Heaters

A water heater's T&P relief valve discharge pipe terminates 6 inches above the floor in a room used for storage. What is the primary concern with this termination?

  1. Discharge could injure a person or damage property, and the termination must be in a safe, visible location Correct answer.
  2. The pipe must terminate outdoors in all cases
  3. The pipe must be smaller than the valve outlet
  4. The pipe is too short to drain properly

Explanation

The relief valve discharge must terminate in a safe place where hot water or steam will not injure anyone or damage property, and it must be visible so discharge is noticed. Terminating where people may stand or store goods is unsafe.

Question 48Fixtures, Fixture Fittings, and Water Heaters

A lavatory is installed with a 1-1/2 inch drain and a 1-1/2 inch trap. The fixture is in a bathroom group with a water closet. Which statement about the trap and fixture drain is correct?

  1. The trap must be at least as large as the fixture drain and sized to the fixture's drainage fixture units Correct answer.
  2. The trap may be one size smaller than the fixture drain
  3. The trap size is determined by the water supply pressure
  4. The trap must be larger than the branch it connects to

Explanation

A fixture trap must be sized for the fixture's drainage load and must not be smaller than the fixture drain it serves. Undersized traps cause self-siphoning and poor drainage.

Question 49Fixtures, Fixture Fittings, and Water Heaters

A drinking fountain is installed in a public building. Which feature is required to prevent backflow contamination of the potable supply?

  1. A thermal expansion tank
  2. An air gap or an approved backflow preventer on the supply Correct answer.
  3. A floor drain beneath the fountain
  4. A pressure-reducing valve on the supply

Explanation

Drinking fountains must be protected against backflow by an air gap or an approved backflow prevention device so that contaminants cannot be drawn into the potable system.

Question 50Fixtures, Fixture Fittings, and Water Heaters

A fixture with a flush tank is installed and the water level rises above the overflow tube, causing continuous running. Which component is most likely at fault?

  1. The trap arm
  2. The stop valve
  3. The flush valve seat
  4. The fill valve or float adjustment Correct answer.

Explanation

If water runs continuously and rises above the overflow tube, the fill valve is not shutting off at the correct level, often due to a misadjusted float or a failed fill valve. The flush valve controls the flush, not the refill level.