Journeyman Plumbers Exam General Plumbing Regulations 5 — Questions and Answers
Question 1: Under IPC, which of the following venting methods allows a single vent pipe to serve multiple fixtures on the same horizontal branch?
- Individual venting
- Wet venting
- Circuit venting (Correct answer)
- Air admittance valves only
Correct answer: Circuit venting
Circuit venting allows a single vent to serve multiple fixtures connected to a common horizontal drain branch.
Question 2: What is the primary reason galvanized steel pipe is rarely used for new potable water installations today?
- It is not approved by any plumbing code
- It corrodes internally, restricting flow and introducing rust into water over time (Correct answer)
- It requires special soldering techniques
- It cannot withstand residential water pressure
Correct answer: It corrodes internally, restricting flow and introducing rust into water over time
Galvanized steel pipe corrodes from the inside out over time, reducing diameter and introducing rust and scale into the water supply.
Question 3: Under IPC, what is required when a plumbing vent pipe passes through a roof?
- It must be capped with a mesh screen to prevent insect entry
- It must extend at least 6 inches above the roof surface (Correct answer)
- It must be increased one pipe size above the roof line
- It must be connected to a stack vent within 12 inches of the roof
Correct answer: It must extend at least 6 inches above the roof surface
The IPC requires vent pipes to extend at least 6 inches above the roof to prevent blockage by snow or debris.
Question 4: A plumber finds that an existing 4-inch cast iron drain is cracked and must be replaced with PVC. The transition coupling used between cast iron and PVC must be:
- A standard PVC slip coupler
- A listed mechanical (Fernco-type) transition coupling (Correct answer)
- A lead and oakum joint
- A threaded iron-to-PVC adapter
Correct answer: A listed mechanical (Fernco-type) transition coupling
A listed mechanical transition (shielded) coupling is required to join dissimilar pipe materials like cast iron and PVC.
Question 5: Which of the following is the correct definition of 'drainage fixture units' (DFU)?
- The volume of water in gallons a fixture discharges per flush
- A unit of measure used to calculate the probable discharge load on a drainage system (Correct answer)
- The number of fixtures allowed per drain stack
- A measure of a fixture's water pressure requirement
Correct answer: A unit of measure used to calculate the probable discharge load on a drainage system
Drainage fixture units (DFU) are a standardized unit used to estimate the probable drainage load that fixtures impose on a sanitary drainage system.
Question 6: Under IPC, what is the maximum horizontal distance a fixture trap can be located from its vent (trap-to-vent distance) for a 2-inch trap arm?
- 4 feet
- 6 feet
- 8 feet (Correct answer)
- 10 feet
Correct answer: 8 feet
For a 2-inch trap arm, the IPC allows a maximum horizontal distance of 8 feet from the trap weir to the vent.
Question 7: Under IPC, when must a backwater valve be installed on a building drain?
- On every building drain regardless of elevation
- When fixtures are located below the elevation of the next upstream manhole in the public sewer (Correct answer)
- Only in commercial buildings over 10,000 square feet
- Whenever the building drain exceeds 6 inches in diameter
Correct answer: When fixtures are located below the elevation of the next upstream manhole in the public sewer
The IPC requires a backwater valve when drainage fixtures are located below the upstream public sewer manhole elevation to prevent sewage backup.
Journeyman Plumbers Exam General Plumbing Regulations 5
Under IPC, which of the following venting methods allows a single vent pipe to serve multiple fixtures on the same horizontal branch?