Free IPC Sanitary Drainage Systems Questions and Answers — Questions and Answers
Question 1: A plumber is installing a horizontal sanitary drainage line for a series of floor drains in a commercial kitchen. The pipe has a diameter of 4 inches. According to IPC Table 704.1, what is the minimum required slope for this pipe?
- 1/16 inch per foot
- 1/4 inch per foot
- 1/2 inch per foot
- 1/8 inch per foot (Correct answer)
Correct answer: 1/8 inch per foot
IPC Table 704.1 specifies the minimum slope for horizontal drainage piping. For pipes with a diameter of 3 to 6 inches, the minimum required slope is 1/8 inch per foot.
Question 2: A wet vent is being installed to serve two full bathroom groups on the same floor. Which of the following is a requirement for this type of installation under the IPC?
- The wet vent can also serve fixtures on the floor below.
- A maximum of one bathroom group can be served by a wet vent.
- Each fixture drain must connect independently to the horizontal wet vent. (Correct answer)
- The dry vent connection must be located downstream of all fixture connections.
Correct answer: Each fixture drain must connect independently to the horizontal wet vent.
According to IPC Section 912.1, any combination of fixtures within two bathroom groups on the same floor level can be vented by a horizontal wet vent. A key requirement is that each wet-vented fixture drain must connect independently to the horizontal wet vent to ensure proper function.
Question 3: When transitioning a sanitary drainage line from horizontal to vertical, which of the following fittings is generally prohibited by the IPC for this specific change in direction?
- Combination wye and 1/8 bend
- 45-degree wye
- Sanitary tee used on its back (Correct answer)
- Long-sweep quarter bend
Correct answer: Sanitary tee used on its back
A sanitary tee is designed for horizontal-to-vertical transitions (e.g., a fixture arm entering a vertical stack). Using it on its back to change flow from a horizontal drain to a vertical drain is prohibited because its short-radius pattern can cause solids to accumulate and lead to blockages.
Question 4: A building's sanitary drainage system is located in a basement, and the fixtures are below the level of the public sewer. What does the IPC require for discharging the waste?
- A gravity-fed drain with an increased slope to overcome the elevation difference.
- Discharge into a tightly covered and vented sump that is automatically pumped to the building drain. (Correct answer)
- Direct connection to the storm drain system, which is typically at a lower elevation.
- Installation of a backwater valve is sufficient to allow for gravity drainage.
Correct answer: Discharge into a tightly covered and vented sump that is automatically pumped to the building drain.
According to IPC Section 712, drainage piping from fixtures located below the level of the public sewer cannot discharge by gravity. The code mandates that such drainage must be collected in a tightly covered and vented sump and then automatically lifted and discharged into the building's gravity drainage system by a sewage pump or ejector.
Question 5: According to the IPC, what is the maximum required spacing between cleanouts on a horizontal sanitary drainage line that is 6 inches in diameter?
- 50 feet
- 75 feet
- 150 feet
- 100 feet (Correct answer)
Correct answer: 100 feet
IPC Section 708.3.1 states that all horizontal drains within buildings shall be provided with cleanouts located not more than 100 feet apart. This requirement applies to pipes of various sizes, including 6-inch diameter lines.
Question 6: Which of the following correctly distinguishes between a 'building drain' and a 'building sewer' as defined by the IPC?
- A building drain serves only sanitary fixtures, while a building sewer serves both sanitary and storm.
- A building drain is the horizontal piping within a building, while the building sewer is the piping outside the building that connects to the public main. (Correct answer)
- The building sewer is always made of cast iron, while the building drain can be PVC or ABS.
- The terms are interchangeable and refer to the same main drainage pipe.
Correct answer: A building drain is the horizontal piping within a building, while the building sewer is the piping outside the building that connects to the public main.
The IPC defines the 'building drain' as the lowest part of a drainage system that receives the discharge from soil, waste, and other drainage pipes inside the walls of the building and conveys it to the building sewer. The 'building sewer' begins outside the building wall and conveys the discharge from the building drain to the public sewer or other point of disposal.
Free IPC Sanitary Drainage Systems Questions and Answers
A plumber is installing a horizontal sanitary drainage line for a series of floor drains in a commercial kitchen.
The pipe has a diameter of 4 inches.
According to IPC Table 704.1, what is the minimum required slope for this pipe?