Journeyman Plumbers Exam General Plumbing Regulations 4 — Questions and Answers
Question 1: Under the IPC, which of the following fixtures requires an individual vent?
- A lavatory within 5 feet of a stack vent
- A floor drain in a basement
- A fixture that cannot be wet vented due to its drainage unit load (Correct answer)
- Any fixture more than 6 feet from the stack
Correct answer: A fixture that cannot be wet vented due to its drainage unit load
When a fixture's drainage load exceeds the allowances for wet venting, it must be individually vented.
Question 2: What is the purpose of a vacuum breaker installed on a hose bibb?
- To regulate water pressure at the outlet
- To prevent backflow of contaminated water into the potable supply (Correct answer)
- To allow air into the pipe to speed drainage
- To reduce water hammer when the hose is disconnected
Correct answer: To prevent backflow of contaminated water into the potable supply
A hose bibb vacuum breaker prevents back-siphonage of potentially contaminated water (from a submerged hose end) into the potable supply.
Question 3: Per IPC, what is the minimum number of plumbing fixtures required for a business occupancy with 1–15 employees?
- 1 water closet, 1 lavatory (Correct answer)
- 2 water closets, 2 lavatories
- 1 water closet only
- 1 lavatory only
Correct answer: 1 water closet, 1 lavatory
IPC Table 403.1 requires at least 1 water closet and 1 lavatory for occupancies with 1–15 employees.
Question 4: Which of the following best describes a 'critical level' (CL) marking on a backflow prevention device?
- The maximum water pressure rating of the device
- The level below which the device must not be installed to prevent backsiphonage (Correct answer)
- The flood level of the fixture it protects
- The minimum flow rate required for the device to operate
Correct answer: The level below which the device must not be installed to prevent backsiphonage
The CL mark indicates the lowest point of installation to ensure the device functions correctly and prevents back-siphonage.
Question 5: When is a pressure relief valve (T&P valve) required on a water heater?
- Only on electric water heaters
- On all water heaters, regardless of fuel type or capacity (Correct answer)
- Only when the water heater is installed in a basement
- Only on storage-type water heaters over 120 gallons
Correct answer: On all water heaters, regardless of fuel type or capacity
All water heaters must be equipped with a temperature and pressure relief valve to prevent catastrophic failure.
Question 6: Under IPC, what is the minimum vent pipe diameter allowed?
- 1 inch
- 1-1/4 inches (Correct answer)
- 1-1/2 inches
- 2 inches
Correct answer: 1-1/4 inches
The IPC sets 1-1/4 inches as the minimum diameter for any vent pipe.
Question 7: A plumber is roughing in a shower with no curb. Under ADA/IPC accessibility requirements, what is the minimum interior shower size?
- 30 inches × 30 inches
- 30 inches × 60 inches
- 36 inches × 36 inches (Correct answer)
- 60 inches × 30 inches
Correct answer: 36 inches × 36 inches
The IPC requires a minimum shower compartment size of 36 inches × 36 inches for accessible (curbless) showers.
Journeyman Plumbers Exam General Plumbing Regulations 4
Under the IPC, which of the following fixtures requires an individual vent?