PC PC Plumbing Codes & Regulations 2 — Questions and Answers
Question 1: Under the IPC, what is the maximum developed length of a trap arm for a 2-inch drain?
- 3 feet
- 5 feet
- 6 feet (Correct answer)
- 8 feet
Correct answer: 6 feet
The IPC allows a maximum developed length of 6 feet for a 2-inch trap arm from the trap weir to the inner edge of the vent.
Question 2: Which type of backflow prevention device is required when connecting an irrigation system to a potable water supply?
- Air gap
- Atmospheric vacuum breaker
- Reduced pressure zone (RPZ) device (Correct answer)
- Double check valve assembly
Correct answer: Reduced pressure zone (RPZ) device
An RPZ (reduced pressure zone) backflow preventer is required for irrigation systems connected to potable water due to the high hazard from pesticides and fertilizers.
Question 3: Per the IPC, what is the minimum slope per foot required for a horizontal drain pipe with a 3-inch diameter?
- 1/16 inch
- 1/8 inch (Correct answer)
- 1/4 inch
- 1/2 inch
Correct answer: 1/8 inch
The IPC requires a minimum slope of 1/8 inch per foot for horizontal drain pipes with a diameter of 3 inches or greater.
Question 4: In a multi-story building, a plumber installs a stack that carries both soil and waste. What type of stack is this called?
- Soil stack
- Waste stack
- Combination waste and vent stack
- Soil and waste stack (Correct answer)
Correct answer: Soil and waste stack
A vertical pipe that carries both soil (from water closets) and waste (from other fixtures) is called a soil and waste stack.
Question 5: What plumbing code section governs the sizing of water supply piping?
- Chapter 3 — General Regulations
- Chapter 6 — Water Supply and Distribution (Correct answer)
- Chapter 8 — Indirect and Special Waste
- Chapter 10 — Traps, Interceptors, and Separators
Correct answer: Chapter 6 — Water Supply and Distribution
Chapter 6 of the IPC covers water supply and distribution, including the sizing of supply piping based on fixture units and pressure.
Question 6: Which of the following requires a permit in most US jurisdictions according to plumbing codes?
- Replacing a faucet washer
- Clearing a clogged drain
- Installing a new water heater (Correct answer)
- Replacing a toilet flapper
Correct answer: Installing a new water heater
Installing a new water heater typically requires a plumbing permit because it involves connections to both water supply and gas or electrical systems.
PC PC Plumbing Codes & Regulations 2
Under the IPC, what is the maximum developed length of a trap arm for a 2-inch drain?