Free IPC Water Supply and Distribution Questions and Answers — Questions and Answers
Question 1: A new building's water service pipe is being installed in a region with a known frost line depth of 18 inches. According to the IPC, what is the minimum required burial depth for this pipe to prevent freezing?
- At least 12 inches below grade and at least 6 inches below the frost line. (Correct answer)
- Exactly at the frost line of 18 inches.
- A minimum of 12 inches below grade, regardless of the frost line.
- A minimum of 24 inches below grade to be safe.
Correct answer: At least 12 inches below grade and at least 6 inches below the frost line.
IPC Section 305.4 specifies that water service piping must be installed at least 12 inches deep and at least 6 inches below the frost line. This ensures protection from both surface activities and freezing temperatures. In this scenario, being 6 inches below the 18-inch frost line means the pipe must be at least 24 inches deep, which satisfies both conditions.
Question 2: In a residential building, the static water pressure from the municipal supply is measured at 95 psi. What action is required by the IPC to be taken on the water distribution system?
- Install a pressure-reducing valve. (Correct answer)
- No action is required as this pressure is acceptable.
- Install a pressure-relief valve set at 100 psi.
- Notify the water purveyor to lower the main pressure.
Correct answer: Install a pressure-reducing valve.
According to IPC Section 604.8, if the static water pressure is greater than 80 psi, an approved pressure-reducing valve must be installed to reduce the pressure in the building's distribution system to 80 psi or less.
Question 3: When installing a temperature and pressure (T&P) relief valve discharge pipe for a water heater, which of the following is an IPC requirement for the termination point?
- The pipe must be threaded at the end to allow for a cap.
- The termination point must be located in a manner that prevents scalding of occupants. (Correct answer)
- The pipe can terminate directly into the sanitary drainage system.
- The termination must be located a maximum of 2 inches above the floor or flood level rim of a receptor.
Correct answer: The termination point must be located in a manner that prevents scalding of occupants.
IPC Section 504.6 details the requirements for T&P relief valve discharge pipes. A key safety requirement is that the discharge must be directed to a location, such as a floor drain or an indirect waste receptor, and terminate in a way that prevents injury or scalding to building occupants. It must not be capped or directly connected to the drainage system. The maximum termination height is 6 inches above the floor or receptor.
Question 4: A plumber is hydrostatically testing a newly installed potable water supply system. According to the IPC, what is the minimum required test pressure and duration?
- 50 psi for 30 minutes.
- 100 psi for 15 minutes.
- Not less than the working pressure under which it is to be used, for 15 minutes.
- 1.5 times the working pressure, but not less than 100 psi, for 15 minutes. (Correct answer)
Correct answer: 1.5 times the working pressure, but not less than 100 psi, for 15 minutes.
IPC Section 312.5 requires that upon completion, a potable water supply system shall be tested and proved tight. The system must be tested hydrostatically to not less than 1.5 times the working pressure, but not less than 100 psi. The test must be maintained for at least 15 minutes without any leakage.
Question 5: Which of the following locations is mandated by the IPC for the installation of water hammer arrestors?
- On all fixture supplies longer than 5 feet.
- At the base of every water supply riser.
- Where quick-closing valves are installed. (Correct answer)
- Only on hot water lines serving kitchen sinks.
Correct answer: Where quick-closing valves are installed.
IPC Section 604.9 requires that the water distribution system be provided with water hammer arrestors where quick-closing valves (such as those on clothes washers, dishwashers, or single-lever faucets) are installed. This is to absorb the hydraulic shock and prevent damage to pipes and fixtures.
Question 6: To protect the potable water supply from contamination, a potable water inlet to a gravity storage tank must be terminated with an air gap. What is the minimum air gap dimension required by the IPC?
- 1 inch (25 mm).
- Twice the diameter of the effective opening, but not less than 1 inch.
- 6 inches (152 mm).
- 4 inches (102 mm) above the flood level rim of the overflow. (Correct answer)
Correct answer: 4 inches (102 mm) above the flood level rim of the overflow.
IPC Section 606.5.6 specifies that potable water inlets to gravity tanks must be controlled by a fill valve and the inlet must terminate so as to provide an air gap of not less than 4 inches above the overflow.
Free IPC Water Supply and Distribution Questions and Answers
A new building's water service pipe is being installed in a region with a known frost line depth of 18 inches.
According to the IPC, what is the minimum required burial depth for this pipe to prevent freezing?