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North Carolina Pipe Fitter Licensing
Examination — Master Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
- The primary purpose of a backflow preventer in a piping system is to: A. Increase pressure B. Reduce flow velocity C. Prevent contamination of potable water D. Remove air from the system
Backflow preventers stop reverse flow that could contaminate drinking water supplies.
- According to standard plumbing code principles, a master pipe fitter is responsible for: A. Only installing residential fixtures
B. Supervising apprentices and ensuring code compliance C. Performing inspections only D. Selling plumbing materials
B. Supervising apprentices and ensuring code compliance
Master license holders oversee work, ensure compliance with codes, and supervise lower-level personnel.
- The minimum slope for horizontal drainage piping 3 inches or smaller is generally: A. 1/16 inch per foot B. 1/4 inch per foot C. 1 inch per foot D. 1/2 inch per foot
¼ inch per foot ensures proper gravity drainage without solids settling.
- Black steel pipe is most commonly used for: A. Potable water B. Natural gas distribution C. Drainage waste systems D. Stormwater piping
Black steel pipe is commonly used for gas systems due to its strength and pressure rating.
It isolates dissimilar metals to prevent electrochemical corrosion.
- The device that regulates water pressure entering a building is: A. Check valve B. Pressure-reducing valve C. Gate valve D. Ball valve
A PRV maintains safe and consistent pressure within plumbing systems.
- The most accurate tool for measuring pipe diameter is: A. Tape measure B. Framing square C. Caliper D. Level
Calipers provide precise inside and outside diameter measurements.
- Cross-connection control programs are primarily concerned with: A. Energy efficiency B. Pipe insulation C. Drainage slope D. Public health protection
They prevent contamination of potable water systems.
- The function of a trap primer is to: A. Increase pressure B. Maintain water seal in traps C. Vent excess gas D. Remove debris
Trap primers add water to floor drains to maintain the trap seal.
- Schedule 40 PVC pipe refers to: A. Pipe color B. Pipe length C. Wall thickness classification D. Flow rating
Schedule indicates wall thickness and pressure rating.
- A double check valve assembly is typically used for: A. High hazard cross-connections B. Low hazard backflow prevention C. Drainage systems D. Steam lines
Lines must be buried below frost depth to prevent freezing.
- The purpose of vent piping is to: A. Drain water B. Equalize pressure in drainage systems C. Increase flow velocity D. Filter wastewater
Vents prevent siphoning of trap seals and maintain airflow.
- When threading pipe, cutting oil is used to: A. Clean the pipe B. Increase speed C. Reduce friction and heat D. Harden threads
Oil prevents overheating and produces clean threads.
- A hydrostatic test is performed using: A. Air B. Nitrogen C. Steam D. Water
Hydrostatic testing uses water to check for leaks and structural integrity.
- The hazard classification for medical gas systems is: A. Noncritical B. Optional C. Critical life-safety system D. Drainage only
Medical gas systems directly impact patient safety.
- A swing check valve allows flow: A. In both directions B. In one direction only C. At reduced pressure D. With manual operation
It prevents reverse flow automatically.
- The standard fitting used to change direction 90 degrees in drainage piping is: A. Tee B. Cross C. Long sweep elbow D. Coupling
5 psi is common for DWV air testing per code standards.
- A union fitting is used to: A. Change pipe size B. Reduce pressure C. Allow disassembly of piping D. Increase flow rate
Unions allow easy separation without cutting pipe.
- The formula for pipe area is: A. πD B. πr C. πr² D. 2πr
Area of a circle equals π times radius squared.
- In gas piping, sediment traps are installed to: A. Increase pressure B. Collect debris and moisture C. Vent gas D. Measure flow
They prevent contaminants from entering appliances.
- A pressure gauge should be installed: A. Upside down B. Where it can be easily read and serviced C. Underground D. In concealed spaces only
Accessibility ensures monitoring and maintenance.
- Pipe insulation primarily prevents: A. Corrosion only B. Heat loss or gain C. Water contamination D. Pressure spikes
Insulation conserves energy and protects against condensation.
- The most common cause of water hammer is: A. Low pressure B. Sudden valve closure C. Small pipe size D. Vent blockage
It turns the pump on/off based on water level.
- Galvanized pipe is coated with: A. Copper B. Zinc C. Plastic D. Lead
Zinc coating resists corrosion.
- When calculating developed length, you must include: A. Only straight pipe B. Fittings and offsets C. Appliance ratings D. Pipe color
Equivalent lengths of fittings affect pressure drop.
- The safe purge gas commonly used for brazing medical gas lines is: A. Oxygen B. Acetylene C. Nitrogen D. Carbon dioxide
Nitrogen prevents oxidation inside tubing.
- A thermostatic mixing valve blends: A. Air and gas B. Steam and air C. Hot and cold water D. Wastewater and vent air
It maintains safe outlet temperature.
- The primary code adopted in North Carolina for plumbing is: A. International Mechanical Code only B. North Carolina State Plumbing Code C. OSHA Code D. NEC
The state plumbing code governs installation requirements.
- A master license holder may: A. Work without permits B. Ignore inspections C. Obtain permits for large commercial projects D. Avoid continuing education
Air separators prevent air binding in heating systems.
- In vertical drainage stacks, cleanouts are required: A. Nowhere B. At the base of the stack C. Only on roofs D. At every fixture
Cleanouts provide access for maintenance and blockage removal.
- The proper slope for horizontal gas piping is: A. Toward meter B. Toward appliance or drip leg C. Perfectly level D. Upward
Slight slope allows condensate to collect at sediment traps.
- A reduced pressure zone (RPZ) device is required for: A. Low hazard B. High hazard cross-connections C. Drain systems D. Vent systems
RPZ assemblies protect against severe contamination risks.
- The unit used to measure flow rate is: A. PSI B. BTU C. GPM D. Volts
Gallons per minute measures water flow rate.
- When pressure exceeds 80 psi, a: A. Check valve B. Trap primer C. Pressure-reducing valve is required D. Gate valve is removed
Codes require pressure regulation above 80 psi.
- The main purpose of a blueprint is to: A. Sell materials B. Estimate labor only C. Provide installation details and specifications D. Replace inspections
Grease interceptors trap fats and oils before wastewater enters the municipal system.
- The maximum allowable pressure for PVC water piping is: A. 50 psi B. 80 psi C. 160 psi D. 300 psi
PVC schedule 40 and 80 have pressure ratings; typical max is 160 psi for schedule 40.
- Threaded joints in steel piping must be sealed with: A. PTFE tape or pipe dope B. Flux C. Solder D. Solvent cement
A. PTFE tape or pipe dope
Thread sealants prevent leaks in threaded metal connections.
- The purpose of a drip leg in gas piping is to: A. Reduce pressure
B. Collect condensate and debris C. Increase flow velocity D. Seal the system
Drip legs trap moisture and particles, protecting appliances.
- Relief valves in pressurized systems are installed to: A. Reduce velocity B. Increase heat C. Prevent overpressure D. Maintain flow
They automatically discharge fluid if pressure exceeds safe limits.
- For fire sprinkler systems, the main type of pipe used is: A. PVC only B. Copper only C. Steel or CPVC D. Lead
Sprinkler systems require materials rated for high temperature and pressure.
