Master Plumber Exam Plumbing Codes and Standards 3 — Questions and Answers
Question 1: Under the IPC, a fixture with a flood rim located below the adjacent roof must be protected against backflow by which device?
- Pressure vacuum breaker
- Atmospheric vacuum breaker
- Reduced pressure zone assembly
- Air gap (Correct answer)
Correct answer: Air gap
An air gap is the only backflow protection method acceptable when the flood rim is below the roof or other overflow point presenting a high hazard.
Question 2: Per the IPC, what is the required minimum air gap distance for a kitchen sink faucet with a 1/2-inch supply pipe?
- 1 inch
- 1-1/2 inches (Correct answer)
- 2 inches
- 3 inches
Correct answer: 1-1/2 inches
The IPC requires an air gap of at least 1-1/2 times the effective opening diameter, with a minimum of 1 inch, but the standard minimum for most fixtures is 1 inch for supply openings up to 1/2 inch.
Question 3: Under the IPC, which of the following fixtures requires a floor drain to be installed within a specific proximity under certain occupancy conditions?
- Kitchen sink
- Water heater relief valve discharge (Correct answer)
- Laundry tub
- Ice maker
Correct answer: Water heater relief valve discharge
The IPC requires the T&P relief valve discharge to terminate to the outside, a safe pan, or within 6 inches of the floor or to a floor drain.
Question 4: According to the IPC, the developed length of a trap arm for a 1-1/2 inch trap shall not exceed:
- 3 feet 6 inches
- 5 feet (Correct answer)
- 6 feet
- 8 feet
Correct answer: 5 feet
Per IPC Table 909.1, a 1-1/2 inch diameter trap arm has a maximum developed length of 5 feet to the vent.
Question 5: Per the IPC, which of the following is NOT a recognized method of venting a plumbing system?
- Individual venting
- Common venting
- Wet venting
- Cross venting (Correct answer)
Correct answer: Cross venting
Cross venting is not a recognized venting method under the IPC; approved methods include individual, common, wet, circuit, and combination drain and vent.
Question 6: Under the IPC, a wet vent serving a bathroom group must be sized based on the:
- Total drainage fixture units of the wet-vented fixtures only (Correct answer)
- Total DFUs of all fixtures served plus the vent pipe sizing table
- Supply fixture units of connected fixtures
- Length of the wet vent pipe only
Correct answer: Total drainage fixture units of the wet-vented fixtures only
A wet vent must be sized to accommodate the drainage fixture unit load of all fixtures it serves, per IPC Section 912.
Question 7: Per the IPC, what is the minimum distance a vent terminal must be located from a window that can be opened?
- 2 feet
- 3 feet (Correct answer)
- 4 feet
- 10 feet
Correct answer: 3 feet
The IPC requires vent terminals to be located at least 3 feet from any door, window, or air intake opening to prevent sewer gases from entering the building.
Master Plumber Exam Plumbing Codes and Standards 3
Under the IPC, a fixture with a flood rim located below the adjacent roof must be protected against backflow by which device?