IPC - International Plumbing Code Plumbing Fixtures and Fittings 2 — Questions and Answers
Question 1: A plumber is roughing in a residential shower compartment. According to the IPC, what is the minimum required floor area for a shower compartment, and what is the minimum allowable dimension in any direction?
- 625 square inches with no dimension less than 25 inches
- 900 square inches with no dimension less than 30 inches (Correct answer)
- 1,024 square inches with no dimension less than 32 inches
- 784 square inches with no dimension less than 28 inches
Correct answer: 900 square inches with no dimension less than 30 inches
IPC Section 608.4.2 requires shower compartments to have a minimum floor area of 900 square inches, with no dimension measuring less than 30 inches. This ensures adequate space for safe use and access, and a 30-inch × 30-inch square is the smallest compliant footprint.
Question 2: During a bathtub installation, the inspector verifies the overflow outlet position. According to the IPC, the overflow inlet must be located at what minimum distance below the bathtub's flood-level rim?
- 1/2 inch below the flood-level rim
- 1 inch below the flood-level rim (Correct answer)
- 1-1/2 inches below the flood-level rim
- 2 inches below the flood-level rim
Correct answer: 1 inch below the flood-level rim
IPC Section 407.2 requires that the overflow inlet of a bathtub be positioned not less than 1 inch below the flood-level rim of the tub. This placement ensures the overflow activates before water can spill over the rim, protecting against flooding.
Question 3: A plumber is selecting and installing a urinal in a commercial men's restroom. What does the IPC require regarding the trap for a wall-hung urinal?
- The urinal must connect to a standard P-trap installed in the wall cavity within 12 inches of the fixture outlet
- The urinal must connect to a drum trap installed below the finished floor
- The urinal must be of the integral trap type, incorporating the trap within the fixture itself (Correct answer)
- No trap is required for urinals if the branch drain is within 5 feet of a vented stack
Correct answer: The urinal must be of the integral trap type, incorporating the trap within the fixture itself
IPC Section 1002.2 requires that urinals be of the integral trap type — meaning the trap is built into the fixture body rather than added externally. This design prevents sewer gases from entering the space while accounting for the unique geometry of urinal drainage.
Question 4: A standpipe receptor is being installed to accept discharge from a residential clothes washing machine. According to the IPC, what are the required minimum and maximum heights for the standpipe measured from the trap weir?
- Minimum 12 inches, maximum 30 inches
- Minimum 18 inches, maximum 42 inches (Correct answer)
- Minimum 24 inches, maximum 48 inches
- Minimum 6 inches, maximum 36 inches
Correct answer: Minimum 18 inches, maximum 42 inches
IPC Section 802.3 specifies that standpipe receptors for clothes washers must extend a minimum of 18 inches and a maximum of 42 inches above the trap weir. This range accommodates the washing machine's discharge hose height while preventing the hose from being submerged in backflow water.
Question 5: A contractor is specifying water closets for a new office building. According to the IPC, what is the maximum allowable water consumption per flush for a flushometer-valve or tank-type water closet?
- 1.28 gallons per flush
- 1.6 gallons per flush (Correct answer)
- 2.0 gallons per flush
- 3.5 gallons per flush
Correct answer: 1.6 gallons per flush
IPC Section 402.2 sets the maximum flush volume for water closets at 1.6 gallons per flush (gpf). This is a federal standard incorporated into the IPC to conserve water. Some high-efficiency models use 1.28 gpf, but 1.6 gpf is the code-maximum permitted by the IPC.
Question 6: A plumbing inspector is verifying a newly installed P-trap beneath a bathroom lavatory. According to the IPC, what are the required minimum and maximum liquid seal depths for the trap?
- Minimum 1 inch, maximum 2 inches
- Minimum 1-1/2 inches, maximum 3 inches
- Minimum 2 inches, maximum 4 inches (Correct answer)
- Minimum 2 inches, maximum 6 inches
Correct answer: Minimum 2 inches, maximum 4 inches
IPC Section 1002.1 requires that fixture traps maintain a liquid seal of not less than 2 inches and not more than 4 inches. A seal shallower than 2 inches can evaporate or siphon away quickly, allowing sewer gases to enter, while a seal deeper than 4 inches increases the risk of self-siphonage and sluggish drainage.
IPC - International Plumbing Code Plumbing Fixtures and Fittings 2
A plumber is roughing in a residential shower compartment.
According to the IPC, what is the minimum required floor area for a shower compartment, and what is the minimum allowable dimension in any direction?