Journeyman Plumber Exam — Questions and Answers

Question 1: Which document primarily governs plumbing installations in most US jurisdictions?

NFPA 13
ANSI A112.18
International Plumbing Code (IPC) or Uniform Plumbing Code (UPC) (Correct answer)
OSHA 29 CFR 1910

Correct answer: International Plumbing Code (IPC) or Uniform Plumbing Code (UPC)

Most US jurisdictions adopt either the IPC or UPC as their primary plumbing code.

Question 2: When installing a water service line, what is the general code requirement for the minimum horizontal separation distance between the potable water line and a sanitary sewer line in the same trench?

The water line must be placed on a shelf 12 inches above the sewer line. (Correct answer)
A minimum of 18 inches is required, regardless of pipe material.
The pipes must be separated by at least 5 feet of undisturbed earth.
There is no minimum separation if the sewer pipe is cast iron.

Correct answer: The water line must be placed on a shelf 12 inches above the sewer line.

To prevent contamination of the potable water supply in case of a leak, plumbing codes mandate specific separation requirements. The most common rule is that if the water line and sewer line are in the same trench, the water line must be placed on a solid shelf of earth at least 12 inches above the top of the sewer line. If they are at the same elevation, a much greater horizontal separation is required.

Question 3: A bathtub overflow drain is required primarily to:

Provide venting for the drain
Limit water depth and prevent flooding (Correct answer)
Prevent siphonage of the trap seal
Equalize pressure in the drain line

Correct answer: Limit water depth and prevent flooding

The overflow drain prevents water from exceeding a safe depth in the tub, protecting against accidental flooding.

Question 4: A plumber needs to install a 45-degree offset. The horizontal distance between the centerlines of the two parallel pipes, known as the 'set', is 20 inches. What is the center-to-center length of the 'travel' piece of pipe?

24 1/2 inches
34 5/8 inches
28 1/4 inches (Correct answer)
20 inches

Correct answer: 28 1/4 inches

To find the travel for a 45-degree offset, you multiply the 'set' by the constant 1.414. In this case, 20 inches (set) x 1.414 = 28.28 inches. The closest fractional answer is 28 1/4 inches (28.25).

Question 5: A plumber uses a pipe with an outside diameter of 4.5 inches and needs to determine the centerline radius when installing a 90-degree bend with a 1.5D radius. What is the centerline radius?

9.00 inches
3.375 inches
4.50 inches
6.75 inches (Correct answer)

Correct answer: 6.75 inches

Centerline radius = 1.5 × outside diameter = 1.5 × 4.5 = 6.75 inches.

Question 6: What fitting constant (take-out) is used when calculating the cut length of pipe for a standard 90-degree elbow?

Always 1 inch regardless of pipe size
Always 2 inches regardless of pipe size
The take-out varies by pipe size and elbow type (Correct answer)
Always equal to the pipe diameter

Correct answer: The take-out varies by pipe size and elbow type

Take-out (fitting allowance) varies by pipe diameter and elbow type and must be looked up in a fittings table.

Question 7: If an isometric drawing shows a trap with a vent line rising vertically from the trap arm, what type of venting does this most likely represent?

An air admittance valve
An individual or unit vent (Correct answer)
A wet vent
A loop vent

Correct answer: An individual or unit vent

A vent line rising vertically from the trap arm on an isometric drawing represents an individual or unit vent connecting to the vent stack.

Question 8: Which showerhead flow rate does the current federal Energy Policy Act limit residential showerheads to?

2.5 gpm (Correct answer)
2.0 gpm
3.0 gpm
1.5 gpm

Correct answer: 2.5 gpm

The federal Energy Policy Act limits residential showerheads to a maximum flow rate of 2.5 gallons per minute at 80 psi.

Question 9: An isometric drawing shows an air admittance valve (AAV) terminating the vent on a kitchen sink island. What is the minimum height above the drain inlet an AAV must be installed?

12 inches
2 inches
6 inches
4 inches (Correct answer)

Correct answer: 4 inches

An AAV must be installed a minimum of 4 inches above the drain inlet it serves to function properly and prevent submersion.

Question 10: Which of the following appliances requires a 100% safety shutoff (automatic gas valve) as part of its control system?

Gas range cooktop
Decorative fireplace log lighter
Residential gas boiler with standing pilot (Correct answer)
Outdoor grill

Correct answer: Residential gas boiler with standing pilot

Residential gas boilers must have a 100% safety shutoff control that automatically closes the gas valve if the pilot or ignition fails, preventing unburned gas accumulation.

Question 11: What is the maximum allowable pressure drop for a gas piping system serving appliances on a low-pressure system (under 2 psi)?

1.0 inches water column
2.0 inches water column
0.5 inches water column (Correct answer)
0.3 inches water column

Correct answer: 0.5 inches water column

Low-pressure gas systems (under 2 psi) are typically designed for a maximum allowable pressure drop of 0.5 inches water column from the meter to the appliance.

Question 12: An isometric drawing shows a horizontal pipe run that must clear an obstruction by using a vertical offset. If the developed length (travel) of the pipe between the two 45-degree fittings is 50 inches, what is the vertical height (offset) gained?

25 inches
35.35 inches (Correct answer)
70.7 inches
50 inches

Correct answer: 35.35 inches

To find the offset (vertical height) from a known travel length in a 45-degree offset, divide the travel length by the constant 1.414 or multiply by 0.707. Calculation: 50 inches / 1.414 = 35.36 inches.

Question 13: A gas furnace is classified as a Category I appliance. This means its vent operates at:

Non-positive pressure and flue gases above dew point (no condensation) (Correct answer)
Positive pressure and produces excessive condensate
Negative pressure with excessive condensation
Positive pressure with no condensation

Correct answer: Non-positive pressure and flue gases above dew point (no condensation)

Category I appliances operate at non-positive vent pressure and produce flue gases warm enough to avoid condensation in the vent.

Question 14: An atmospheric gas water heater is installed in a confined mechanical room. What is required to ensure safe operation?

An exhaust fan rated for continuous duty
No additional provisions if the room has a door
A carbon monoxide detector only
A dedicated combustion air supply to the confined space (Correct answer)

Correct answer: A dedicated combustion air supply to the confined space

Atmospheric gas water heaters require adequate combustion air; when installed in a confined space, openings or ducts providing a dedicated combustion air supply from outside or an adjacent unconfined space are required.

Question 15: What is the minimum clearance required between an unprotected gas appliance vent connector and combustible material?

9 inches
12 inches
18 inches
6 inches (Correct answer)

Correct answer: 6 inches

NFPA 54 requires a minimum 6-inch clearance between an unprotected single-wall metal vent connector and combustible materials.

Question 16: What is the primary purpose of a P-trap in a drainage system?

To increase water velocity in the drain
To maintain a water seal that blocks sewer gases (Correct answer)
To allow air into the drain line
To reduce the slope of the horizontal drain

Correct answer: To maintain a water seal that blocks sewer gases

A P-trap retains a water seal that prevents sewer gases and odors from entering the building through the fixture drain.

Question 17: When gas piping passes through a wall, floor, or ceiling, it must be protected by:

No protection is required
A rubber grommet
A sleeve or protective coating (Correct answer)
A metal conduit pipe

Correct answer: A sleeve or protective coating

Gas piping penetrating walls, floors, or ceilings must be protected with a sleeve or protective coating to prevent abrasion damage to the pipe.

Question 18: Where must an air admittance valve (AAV) NOT be installed?

In a wall cavity
Below grade or in a sealed space without air (Correct answer)
In an attic
Above the flood level rim of a fixture

Correct answer: Below grade or in a sealed space without air

AAVs require access to air to function; they cannot be installed below grade or in any sealed space where air is unavailable.

Question 19: A plumber needs to cut a piece of copper pipe to connect two 90-degree wrought copper elbows. The center-to-center measurement between where the fittings will be is 36 inches. The fitting allowance (take-off) for each elbow is 3/4 inch. What is the required end-to-end cut length of the pipe?

36 inches
37 1/2 inches
35 1/4 inches
34 1/2 inches (Correct answer)

Correct answer: 34 1/2 inches

To find the cut length of the pipe, the take-off for both fittings must be subtracted from the center-to-center measurement. The pipe fits into the sockets of the fittings. Calculation: 36" - (3/4" + 3/4") = 36" - 1 1/2" = 34 1/2 inches.

Question 20: What is the greatest possible separation between an accessible toilet faucet and the front edge of the toilet?

25 inches (Correct answer)
18 inches
28 inches
16 inches

Correct answer: 25 inches

When the fixture is meant for handicap usage, bathroom faucets must be placed no more than 25 inches from the front border of the lavatory they are serving.

Question 21: Which of the following is a code requirement for the installation of cleanouts in a horizontal drainage system?

A cleanout is required every 50 feet on straight runs.
Cleanouts must be installed at each 45-degree change in direction.
The minimum size for any cleanout is 2 inches.
Cleanouts are required for each run of piping more than 100 feet in total developed length. (Correct answer)

Correct answer: Cleanouts are required for each run of piping more than 100 feet in total developed length.

Model plumbing codes, such as the IPC and UPC, require that horizontal drainage pipes be provided with a cleanout for each 100 feet of developed length, or fraction thereof. They are also required at the upper end of each horizontal drain and for aggregate changes in direction exceeding 135 degrees.

Question 22: What is the required pressure test for new gas piping before placing it in service under the International Fuel Gas Code?

50 psi for 1 hour
10 psi for 15 minutes
1.5 times the operating pressure for 10 minutes
3 psi for 10 minutes (Correct answer)

Correct answer: 3 psi for 10 minutes

New gas piping systems must be pressure tested at no less than 3 psi gauge for a minimum of 10 minutes to verify there are no leaks before the gas is turned on.

Question 23: When testing a DWV system with water, to what height must the water column be maintained above the highest point of the system?

10 feet (Correct answer)
3 feet
The entire system must be filled to the highest vent opening
5 feet

Correct answer: 10 feet

A water test requires the system to be filled to a 10-foot head of water above the highest point being tested, per the UPC.

Question 24: A kitchen sink strainer basket must have a minimum opening size of:

3/4 inch
3/8 inch (Correct answer)
1/4 inch
1/2 inch

Correct answer: 3/8 inch

Kitchen sink strainer baskets must have openings no smaller than 3/8 inch to allow adequate drainage while catching food particles.

Question 25: When a gas meter is located inside a building, it must be installed in a location that is:

Below the gas appliance served
Ventilated and accessible (Correct answer)
Adjacent to the main electrical panel
In a locked utility closet

Correct answer: Ventilated and accessible

Gas meters installed indoors must be in a ventilated, accessible location to allow for meter reading, maintenance, and safe dispersal of any gas leaks.

Question 26: A plumber connects a chemical feed pump directly to a potable water line without any backflow protection. This is best described as:

Allowable when approved by the building owner in writing
A permitted connection if the pump has an internal check valve
Acceptable only if the pump is downstream of a water meter
An illegal cross-connection creating a high-hazard condition (Correct answer)

Correct answer: An illegal cross-connection creating a high-hazard condition

Any direct connection between a chemical feed system and the potable supply without proper backflow protection is an illegal high-hazard cross-connection.

Question 27: When installing a gas range in a kitchen, the flexible connector used must NOT exceed what length?

10 feet
3 feet
2 feet
6 feet (Correct answer)

Correct answer: 6 feet

Appliance connectors for gas ranges and similar equipment must not exceed 6 feet in length per NFPA 54.

Question 28: On a fire sprinkler system connected to the potable supply, the isolation valves on the backflow preventer assembly must be which type?

Ball valves that open and close with a quarter turn
Check valves that allow flow in one direction only
Gate valves without locking devices
Indicating-type valves (OS&Y or butterfly with tamper switch) (Correct answer)

Correct answer: Indicating-type valves (OS&Y or butterfly with tamper switch)

Fire system isolation valves must be indicating-type (such as OS&Y gate valves or supervised butterfly valves) so it can be visually confirmed whether they are open or closed.

Question 29: Which of the following is an example of a high-hazard cross-connection?

A lawn sprinkler system with no fertilizer injection
A garden hose left in a bucket of soapy water
A carbonated beverage dispenser connected to potable water (Correct answer)
A water softener bypass line

Correct answer: A carbonated beverage dispenser connected to potable water

Carbonated beverage dispensers create a high-hazard cross-connection because CO2 and syrup can be siphoned back into the potable supply.

Question 30: Which of the following conditions ALWAYS requires a licensed plumber or gas fitter to obtain a permit before work begins?

Cleaning a burner orifice
Installing new gas piping or extending an existing gas line (Correct answer)
Lighting a pilot light
Replacing an existing gas appliance connector (same size)

Correct answer: Installing new gas piping or extending an existing gas line

Any new gas piping installation or extension of an existing gas system requires a permit to ensure the work is inspected and meets code.

Question 31: Which backflow device is NOT acceptable for use under continuous supply pressure?

Double check valve assembly (DCVA)
Reduced pressure zone (RPZ)
Pressure vacuum breaker (PVB)
Atmospheric vacuum breaker (AVB) (Correct answer)

Correct answer: Atmospheric vacuum breaker (AVB)

Atmospheric vacuum breakers must not be subjected to continuous supply pressure exceeding 12 hours as it can hold the check open, defeating the device.

Question 32: A sediment trap (drip leg) in a gas line is installed to:

Prevent backflow of gas
Measure gas flow rate
Reduce gas pressure before the appliance
Collect condensate and debris before they enter the appliance (Correct answer)

Correct answer: Collect condensate and debris before they enter the appliance

A sediment trap collects moisture and pipe scale, preventing them from entering the gas valve or burner of the appliance.

Question 33: A gas dryer vent must terminate:

Into the attic to keep moisture away from living areas
At least 3 feet from any opening into the building (Correct answer)
Through the floor to grade level
Into the crawlspace

Correct answer: At least 3 feet from any opening into the building

Dryer exhaust vents must terminate outdoors at least 3 feet from any building opening such as windows, doors, or vents to prevent re-entry of combustion products.

Question 34: A combination waste and vent system is typically used for:

Multistory high-rise buildings
Floor drains and sinks in slab-on-grade commercial kitchens where conventional venting is impractical (Correct answer)
Outdoor hose bibbs and yard drains
Water closets in basement bathrooms only

Correct answer: Floor drains and sinks in slab-on-grade commercial kitchens where conventional venting is impractical

Combination waste and vent systems use oversized horizontal drain pipes as both the drain and vent, and are commonly applied to floor drains in slab construction where vertical venting is difficult.

Question 35: A plumber is installing the drain for a kitchen sink, which has a 1-1/2 inch P-trap. What is the maximum horizontal distance the trap arm can be from the vent fitting?

6 feet
8 feet
3 feet 6 inches (Correct answer)
5 feet

Correct answer: 3 feet 6 inches

The maximum horizontal distance between a fixture trap and its vent is determined by the size of the trap arm. For a 1-1/2 inch pipe, this distance is typically limited to 3 feet 6 inches to ensure proper venting and prevent the trap from being siphoned.

Question 36: What is the maximum hot water temperature allowed at a residential shower per the IPC?

110°F
115°F
120°F (Correct answer)
125°F

Correct answer: 120°F

The IPC limits shower water temperature to 120°F (49°C) maximum to prevent scalding injuries.

Question 37: Which type of fixture trap is prohibited by the IPC in most applications?

P-trap
Drum trap
S-trap (Correct answer)
Running trap

Correct answer: S-trap

S-traps are prohibited because their configuration causes self-siphoning, which empties the water seal and allows sewer gases to enter.

Question 38: Which type of gas valve is required to be installed immediately upstream of each gas appliance?

Check valve
Pressure relief valve
Accessible manual shutoff valve (Correct answer)
Ball valve only

Correct answer: Accessible manual shutoff valve

An accessible manual shutoff valve must be installed within 6 feet of each appliance to allow quick isolation in an emergency.

Question 39: What must be installed where gas piping passes through a foundation wall or concrete floor slab?

A protective sleeve or casing (Correct answer)
A dielectric union
An expansion loop
A shutoff valve

Correct answer: A protective sleeve or casing

Gas pipe must be sleeved where it passes through masonry or concrete to protect it from corrosion, soil movement, and to allow for expansion.

Question 40: What test pressure is typically used to pressure-test a new gas piping system before it is placed into service?

50 psig regardless of operating pressure
10 inches W.C.
Line pressure (standard operating pressure)
1.5 times the operating pressure, minimum 3 psig (Correct answer)

Correct answer: 1.5 times the operating pressure, minimum 3 psig

NFPA 54 requires new gas piping to be tested at a pressure of at least 1.5 times the operating pressure or a minimum of 3 psig, whichever is greater.

Question 41: A plumber has a travel piece that is 35 inches long and was installed using two 45-degree fittings. What is the offset distance between the centerlines of the two parallel pipes?

35 inches
17.5 inches
24.75 inches (Correct answer)
49.5 inches

Correct answer: 24.75 inches

To find the offset when the travel length is known, you multiply the travel by 0.707 (the reciprocal of 1.414) or divide the travel by 1.414. Calculation: 35 inches * 0.707 = 24.745 inches, which rounds to 24.75 inches.

Question 42: A circuit vent is connected to a horizontal branch drain at what location relative to the fixture connections?

Downstream of the last fixture (Correct answer)
At the stack connection
Upstream of the first fixture
Between the first and last fixtures

Correct answer: Downstream of the last fixture

A circuit vent connects to the horizontal branch drain downstream (below) the last fixture connection on that branch.

Question 43: A natural gas vent for a Category I appliance terminates through a pitched roof. What is the minimum height the vent must extend above the point where it passes through the roof surface?

24 inches
6 inches
18 inches
12 inches (Correct answer)

Correct answer: 12 inches

According to typical fuel gas codes, a vent must terminate at least a certain height above the roof to ensure proper draft and prevent blockage from snow or debris. For vents passing through a roof, a common minimum height requirement is 12 inches (1 foot), though this can increase depending on the roof pitch and proximity to vertical surfaces. For example, some codes require termination at least 2 feet higher than any portion of the building within 10 feet.

Question 44: When reading an isometric drawing of a DWV system, a 45° wye fitting is shown. What is its primary purpose?

To increase pipe diameter
To connect supply and drain lines
To allow a branch drain to tie into a main drain at a gradual angle (Correct answer)
To reverse the flow direction

Correct answer: To allow a branch drain to tie into a main drain at a gradual angle

A 45° wye fitting allows a branch line to enter a main drain at 45°, promoting smooth drainage flow and reducing clogs.

Question 45: A gas appliance vent connector should slope upward toward the vent at a minimum of:

1/2 inch per foot
1 inch per foot
1/8 inch per foot
1/4 inch per foot (Correct answer)

Correct answer: 1/4 inch per foot

Vent connectors must rise at least 1/4 inch per foot toward the vent to ensure proper draft and prevent condensate from collecting in low spots.

Question 46: A circuit vent serves:

A battery of fixtures connected to a common horizontal branch drain (Correct answer)
A single fixture on an upper floor
The main soil stack above the roof
Only floor drains in a single room

Correct answer: A battery of fixtures connected to a common horizontal branch drain

A circuit vent serves a group (battery) of fixtures connected to a horizontal branch drain and provides venting for all fixtures in the group with one vent connection.

Question 47: An isometric drawing shows a backflow preventer on a domestic water service. What is its function?

To filter sediment from the supply
To boost water pressure to upper floors
To prevent contaminated water from flowing back into the potable supply (Correct answer)
To meter water usage

Correct answer: To prevent contaminated water from flowing back into the potable supply

A backflow preventer stops contaminated or non-potable water from reversing into the potable water supply due to back-pressure or back-siphonage.

Question 48: A manual shutoff valve must be installed within what distance of each gas appliance?

3 feet
10 feet
5 feet
6 feet (Correct answer)

Correct answer: 6 feet

The IFGC requires a manual shutoff valve to be installed within 6 feet of each gas appliance to allow for quick isolation in an emergency.

Question 49: A floor drain trap primer is used to:

Periodically supply water to a floor drain trap to prevent the seal from evaporating (Correct answer)
Increase the flow rate through the floor drain
Prime the sewer ejector pump before use
Clean the floor drain screen automatically

Correct answer: Periodically supply water to a floor drain trap to prevent the seal from evaporating

Trap primers supply small amounts of water to infrequently used floor drain traps to replace water lost to evaporation and maintain the sewer gas seal.

Question 50: Where must a temperature and pressure (T&P) relief valve discharge pipe terminate?

Directly into a floor drain
Within 6 inches of the floor (Correct answer)
Into the cold water supply line
At least 24 inches above the floor

Correct answer: Within 6 inches of the floor

T&P relief valve discharge pipes must terminate within 6 inches of the floor to direct scalding water safely downward away from occupants.

Question 51: A sanitary drain must run 40 feet at a slope of 1/4 inch per foot. How much lower is the downstream end compared to the upstream end?

5 inches
12 inches
8 inches
10 inches (Correct answer)

Correct answer: 10 inches

Total drop = 40 feet × 0.25 inches/foot = 10 inches.

Question 52: A plumber is installing an island sink in a kitchen where a conventional vent through a wall is not feasible. Which of the following specialty vents is specifically designed for this application to prevent trap siphonage?

Island Fixture Vent (Loop Vent) (Correct answer)
Circuit Vent
Common Vent
Air Admittance Valve

Correct answer: Island Fixture Vent (Loop Vent)

An Island Fixture Vent, also known as a loop vent, is a code-approved method for venting fixtures that are not adjacent to a wall. It works by extending the vent up as high as possible under the counter, looping it over, and then running it down to connect to a horizontal drain that is itself vented elsewhere, effectively protecting the trap seal from siphonage.

Question 53: The BTU content of one cubic foot of natural gas is approximately:

5,000 BTU
1,000 BTU (Correct answer)
2,500 BTU
500 BTU

Correct answer: 1,000 BTU

Natural gas contains approximately 1,000 BTU per cubic foot, a value used in load calculations when sizing gas piping and meters.

Question 54: Which document primarily governs gas piping installation standards for most US jurisdictions?

IPC (International Plumbing Code)
NEC (National Electrical Code)
NFPA 54 / International Fuel Gas Code (IFGC) (Correct answer)
ASME B31.1 Power Piping

Correct answer: NFPA 54 / International Fuel Gas Code (IFGC)

NFPA 54 (National Fuel Gas Code) and its companion IFGC are the primary standards adopted by most US jurisdictions for fuel gas piping installation.

Question 55: The plumbing that transports potable water from a water source to a water distribution system is referred to as which of the following?

Water supply
Either water main and water supply (Correct answer)
None of the above
Water main

Correct answer: Either water main and water supply

A water main or a water supply is the main conduit that transports potable water to a water-distribution system. Regardless of whether the water is flowing from a municipal water system or a water well, this is the situation. A water supply pipe must have a minimum diameter of.75 inches.

Question 56: A newly installed copper potable water distribution system in a commercial building must be tested for leaks. According to most model plumbing codes, what is the minimum required hydrostatic test pressure?

100 psi or the working pressure, whichever is less
1.5 times the working pressure, but not less than 100 psi (Correct answer)
1.25 times the working pressure
Equal to the street main pressure

Correct answer: 1.5 times the working pressure, but not less than 100 psi

Most plumbing codes, including the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), require a hydrostatic test pressure of at least 1.5 times the system's working pressure. Additionally, there is often a minimum requirement, typically 100 psi, to ensure a thorough test even in low-pressure systems. This high pressure will reveal any leaks at joints or defects in the piping.

Question 57: What is the minimum number of fixture units a 4-inch building drain can carry at 1/4-inch-per-foot slope?

96 DFUs
160 DFUs (Correct answer)
216 DFUs
250 DFUs

Correct answer: 160 DFUs

A 4-inch building drain sloped at 1/4 inch per foot has a rated capacity of 160 drainage fixture units (DFUs) per the UPC drainage load tables.

Question 58: What is the purpose of the bypass valve on a backflow preventer assembly installed in a commercial building?

To allow water to flow while the assembly is being tested or repaired (Correct answer)
To reduce system pressure to an acceptable level
To provide an alternate path for backflow to discharge safely
To equalize pressure on both sides of the check valves

Correct answer: To allow water to flow while the assembly is being tested or repaired

A bypass with a backflow preventer allows the building to maintain water service while the primary assembly is taken offline for testing or maintenance.

Question 59: Which type of vent is installed on the downstream side of a fixture trap to prevent siphoning?

Back vent (individual vent) (Correct answer)
Common vent
Circuit vent
Relief vent

Correct answer: Back vent (individual vent)

A back vent, also called an individual vent, connects to the fixture drain on the downstream side of the trap to prevent trap siphoning.

Question 60: When installing a lavatory to meet ADA accessibility standards, which of the following requirements for the pipes under the sink is correct?

Pipes must be concealed within a cabinet.
A mechanical vent must be installed directly under the sink.
Pipes must be insulated or configured to protect against contact. (Correct answer)
Pipes must be made of chrome-plated brass.

Correct answer: Pipes must be insulated or configured to protect against contact.

To comply with ADA standards, the hot water and drain pipes under a lavatory must be insulated or otherwise configured to protect against contact. This prevents individuals in wheelchairs, whose legs may touch the piping, from being burned or injured by sharp or abrasive surfaces.

Question 61: A drain pipe drops 1/4 inch per foot over a run of 32 feet. What is the total drop?

8 inches (Correct answer)
6 inches
4 inches
10 inches

Correct answer: 8 inches

Total drop = 32 feet × 0.25 inches/foot = 8 inches.

Question 62: The least amount of time that the system must be evaluated when evaluating gas piping installed in a single-family home with a volume of less than 10 cubic feet is _________________.

30 minutes
60 minutes
15 minutes
10 minutes (Correct answer)

Correct answer: 10 minutes

A test that is sustained for a minimum of 10 minutes is required for gas piping that is installed in a single-family residence and has a volume of less than 10 cubic feet. More than 24 hours cannot be spent maintaining testing. A manometer is the most widely used testing tool.

Question 63: Which of the following is a correct statement about CSST (corrugated stainless steel tubing)?

CSST may be run through air ducts without restriction
CSST does not require protection where exposed to physical damage
CSST must be bonded and grounded per manufacturer and code requirements (Correct answer)
CSST is interchangeable with flexible appliance connectors

Correct answer: CSST must be bonded and grounded per manufacturer and code requirements

CSST must be bonded to the electrical grounding system to reduce the risk of arc damage from lightning-induced surges.

Question 64: What is the minimum horizontal distance from a vent terminal opening to any window or door that can be opened?

10 feet
3 feet (Correct answer)
2 feet
5 feet

Correct answer: 3 feet

Vent terminal openings must be located at least 3 feet from any openable window, door, or other opening into the building.

Question 65: A pilot light that repeatedly goes out on a gas appliance most likely indicates a problem with:

The thermocouple or thermopile (Correct answer)
The main gas valve
The vent cap
The pressure regulator

Correct answer: The thermocouple or thermopile

The thermocouple generates a small voltage when heated by the pilot flame; if it fails or is positioned incorrectly, it causes the safety valve to close, extinguishing the pilot.

Question 66: A plumber is running an underground polyethylene (PE) gas line to an outdoor barbecue grill. According to the IFGC, how must the PE pipe be transitioned for the above-ground connection to the appliance?

PE pipe can be run directly to the appliance if it is painted yellow for visibility.
A section of copper tubing must be used for the last 18 inches below grade before transitioning above ground.
The PE pipe can extend up to 6 inches above grade if it is sleeved in schedule 40 PVC.
The PE pipe must transition to an approved metallic pipe using a manufactured anodeless riser before it emerges from the ground. (Correct answer)

Correct answer: The PE pipe must transition to an approved metallic pipe using a manufactured anodeless riser before it emerges from the ground.

Polyethylene (PE) plastic piping is not approved for above-ground use due to its susceptibility to UV degradation and physical damage. It must be terminated below grade and connected to an approved above-ground piping material, typically through a pre-manufactured anodeless riser or other approved transition fitting.

Question 67: When a gas appliance is installed in a bedroom or bathroom, which special requirement applies?

No gas appliances are permitted in bedrooms or bathrooms
The gas meter must be indoors
A CO detector must be installed within 1 foot of the appliance
The appliance must be direct-vent or have a sealed combustion chamber (Correct answer)

Correct answer: The appliance must be direct-vent or have a sealed combustion chamber

Gas appliances in sleeping rooms and bathrooms must use direct-vent or sealed combustion systems to prevent combustion air from being drawn from the occupied space.

Question 68: A horizontal drainage pipe that is 48 feet long must be installed with a uniform grade of 1/4 inch per foot. What is the total fall of the pipe from its highest point to its lowest point?

12 inches (Correct answer)
24 inches
6 inches
8 inches

Correct answer: 12 inches

The total fall is calculated by multiplying the length of the pipe in feet by the required grade in inches per foot. Calculation: 48 feet * (1/4 inch/foot) = 12 inches.

Question 69: Which type of backflow prevention device offers the highest level of protection against both back-siphonage and backpressure and is suitable for high-hazard applications?

Double Check Valve Assembly (DCVA)
Reduced Pressure Zone (RPZ) Assembly (Correct answer)
Atmospheric Vacuum Breaker (AVB)
Pressure Vacuum Breaker (PVB)

Correct answer: Reduced Pressure Zone (RPZ) Assembly

A Reduced Pressure Zone (RPZ) Assembly provides the highest level of protection for the potable water supply. It uses two independent check valves and a hydraulically operated differential pressure relief valve located between them, which will discharge water to the atmosphere if either check valve leaks, making it suitable for high-hazard situations involving backpressure or back-siphonage.

Question 70: Which fixture is NOT typically connected to the sanitary drain system?

Floor sink
Drinking fountain
Condensate drain from HVAC (Correct answer)
Laundry tray

Correct answer: Condensate drain from HVAC

HVAC condensate drains are typically routed to an indirect waste receptor or exterior, not directly connected to the sanitary drain system without an air gap.

Question 71: An isometric drawing shows a horizontal drain with a 1/4" per foot slope over a 20-foot run. What is the total drop?

5 inches (Correct answer)
2.5 inches
10 inches
20 inches

Correct answer: 5 inches

Total drop = 1/4" × 20 = 5 inches over the 20-foot horizontal run.

Question 72: A journeyman plumber encounters an existing installation that does not comply with the current code but was legal when installed. This is known as:

An illegal installation subject to fines
A grandfathered or nonconforming installation (Correct answer)
A code violation requiring immediate correction
A variance that must be renewed annually

Correct answer: A grandfathered or nonconforming installation

Installations that were code-compliant when built but no longer meet current code are considered nonconforming (grandfathered) and are generally allowed to remain.

Question 73: What is the minimum required length for a trap arm, as measured from the trap weir to the inner edge of the vent?

One pipe diameter
Four pipe diameters
There is no minimum length requirement.
Two pipe diameters (Correct answer)

Correct answer: Two pipe diameters

The trap arm must be at least two times the diameter of the pipe. This minimum distance prevents the vent from being installed too close to the trap, which would create a prohibited crown vent and could lead to the siphoning of the trap seal.

Question 74: What test is commonly used to check a completed DWV system for leaks before covering it?

Air pressure test at 5 psi or water test filled to the highest point (Correct answer)
Vacuum test at 15 inches Hg
Dye test using colored water from the supply system
Hydrostatic pressure test at 100 psi

Correct answer: Air pressure test at 5 psi or water test filled to the highest point

DWV systems are tested with either an air test at 5 psi or a water test where the system is filled to the level of the highest stack opening, per IPC Section 312.

Question 75: What is the minimum distance an RPZ assembly's relief port discharge must be from a sanitary drain receptor to prevent a cross-connection?

1 inch above the drain rim
An air gap of at least twice the drain receptor diameter
No minimum is required if the drain is covered
The discharge must never connect directly to the drainage system (Correct answer)

Correct answer: The discharge must never connect directly to the drainage system

The RPZ relief port discharge must terminate with an air gap and must never be directly piped into the drainage system to prevent a drainage cross-connection.

Question 76: Under IPC, what is the maximum developed length of a trap arm (from trap weir to vent) for a 1-1/2 inch pipe?

6 feet
5 feet (Correct answer)
3 feet
8 feet

Correct answer: 5 feet

The IPC allows a maximum trap arm length of 5 feet for a 1-1/2 inch pipe.

Question 77: A plumber pressurizes a newly installed gas piping system for a leak test. For a typical residential system tested with air, what is the common minimum test pressure and duration required by code?

Working pressure for 24 hours
5 psi for 10 minutes
10 psi for 15 minutes (Correct answer)
50 psi for 30 minutes

Correct answer: 10 psi for 15 minutes

Most plumbing and fuel gas codes require that a new gas piping system be subjected to a pressure test before being put into service. For a typical residential system, the test pressure must be at least 10 psi, and it must hold this pressure for a minimum of 15 minutes without any drop. The gauge used must be appropriate for this pressure range, typically with 1/10 psi increments.

Question 78: An air admittance valve (AAV) is NOT permitted to:

Replace the main vent stack that terminates to open air (Correct answer)
Serve a single fixture vent on an island sink
Vent a lavatory in a remodel where wall access is limited
Serve a battery of fixtures when permitted by the local code

Correct answer: Replace the main vent stack that terminates to open air

An AAV cannot replace the main vent stack because the drainage system must have at least one open vent pipe to atmosphere to equalize positive pressures.

Question 79: What is the function of the isolation (shut-off) valves that are integral to a testable backflow prevention assembly?

They provide a secondary backflow barrier if both check valves fail
They regulate downstream pressure to protect the check valves from damage
They prevent thermal expansion from building pressure inside the assembly body
They allow the assembly to be isolated for testing and maintenance without shutting down the entire system (Correct answer)

Correct answer: They allow the assembly to be isolated for testing and maintenance without shutting down the entire system

Integral isolation valves allow technicians to isolate the backflow assembly for annual testing and repairs while minimizing disruption to the rest of the system.

Question 80: When installing a wet vent for a bathroom group (e.g., toilet, lavatory, and bathtub), which of the following is a critical requirement according to most plumbing codes?

The wet-vented section must be two pipe sizes larger than the largest fixture drain.
The toilet must always be the most upstream fixture connected to the wet vent.
Only fixtures on different floor levels can be connected to the wet vent.
All fixtures served by the wet vent must be on the same floor level. (Correct answer)

Correct answer: All fixtures served by the wet vent must be on the same floor level.

A key principle of wet venting is that all the interconnected fixtures sharing the vent must be located on the same story or floor level. This ensures the proper hydraulic and pneumatic conditions for the drain to also function as a vent.

Question 81: Under IPC, which of the following venting methods allows a single vent pipe to serve multiple fixtures on the same horizontal branch?

Individual venting
Circuit venting (Correct answer)
Air admittance valves only
Wet venting

Correct answer: Circuit venting

Circuit venting allows a single vent to serve multiple fixtures connected to a common horizontal drain branch.

Journeyman Plumber Exam

The Journeyman Plumber Exam exam validates essential knowledge and skills required for certification or licensure in this field.

Questions

120 min

Time Limit

70%

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