Master Plumber Exam Plumbing Fixtures and Appliances 2 — Questions and Answers
Question 1: What is the minimum water closet compartment width required by most US plumbing codes when a wall-mounted toilet is installed?
- 24 inches
- 30 inches (Correct answer)
- 36 inches
- 18 inches
Correct answer: 30 inches
Most plumbing codes require a minimum 30-inch wide water closet compartment to allow proper access and use.
Question 2: A pressure-balancing valve in a shower is required to limit hot water outlet temperature to a maximum of:
- 110°F
- 120°F (Correct answer)
- 130°F
- 140°F
Correct answer: 120°F
Per ASSE 1016 and most plumbing codes, pressure-balancing valves must limit outlet temperature to a maximum of 120°F to prevent scalding.
Question 3: Which fixture requires a trap with a minimum 3-inch seal depth under most plumbing codes?
- Bathtub
- Urinal
- Floor drain subject to evaporation (Correct answer)
- Kitchen sink
Correct answer: Floor drain subject to evaporation
Floor drains in infrequently used areas may require a 3-inch deep seal trap or a trap primer to prevent seal evaporation.
Question 4: An interceptor is required ahead of a kitchen sink when the sink serves:
- A residential kitchen with a garbage disposal
- A commercial kitchen in a food service establishment (Correct answer)
- Any sink with a dishwasher connection
- A sink with a spray head attachment
Correct answer: A commercial kitchen in a food service establishment
Grease interceptors are required before drainage from commercial food service establishments to prevent grease from entering the public sewer.
Question 5: What type of flush valve mechanism is typically used in a flushometer-valve water closet?
- Float ball and fill valve
- Direct-flush valve with diaphragm or piston (Correct answer)
- Gravity tank with siphon jet
- Pressure-assisted tank mechanism
Correct answer: Direct-flush valve with diaphragm or piston
Flushometer valves use a direct-pressure diaphragm or piston mechanism that opens directly to supply pressure, requiring no tank.
Question 6: When installing a bidet, the supply fitting must include which protection device to prevent backflow?
- Air gap
- Pressure vacuum breaker or atmospheric vacuum breaker (Correct answer)
- Double check valve assembly
- Reduced pressure zone device
Correct answer: Pressure vacuum breaker or atmospheric vacuum breaker
Bidet supply fittings require a vacuum breaker because the outlet may be submerged, creating a cross-connection risk that requires backflow prevention.
Question 7: A lavatory installed in a healthcare facility must have a minimum basin size of:
- 12 inches × 12 inches
- 17 inches × 14 inches (Correct answer)
- 18 inches × 16 inches
- 20 inches × 18 inches
Correct answer: 17 inches × 14 inches
Healthcare lavatories typically require a minimum basin area of 17 × 14 inches per fixture standards to accommodate hand-washing procedures.
Master Plumber Exam Plumbing Fixtures and Appliances 2
What is the minimum water closet compartment width required by most US plumbing codes when a wall-mounted toilet is installed?