GAS FITTER LEVEL C CERTIFICATION EXAM
QUESTIONS AND CORRECT ANSWERS
1. What is the primary purpose of a pressure regulator in a gas
system?
To maintain a consistent downstream pressure
It ensures appliances receive gas at a safe and consistent pressure
regardless of fluctuations in supply.
2. Which type of gas is commonly used in residential applications for
cooking and heating?
Natural gas
Natural gas is widely available and preferred for residential use due
to its clean-burning properties.
3. What is the correct action if a gas leak is detected during
inspection?
Shut off the gas supply immediately and ventilate the area Gas
leaks are hazardous; immediate shut-off and ventilation prevent
fire or explosion risks.
4. When joining steel pipes for gas installation, which method is
standard?
Threaded connections with proper sealing compounds Threaded
joints provide mechanical strength and sealing, preventing gas
leaks.
5. What is the maximum allowable pressure for a residential natural gas
system?
1/2 psi (3.5 kPa)
Residential systems operate at low pressure; exceeding this can damage
appliances or piping.
, 6. Which device prevents gas from flowing backward in a pipeline?
Check valve
Check valves allow gas to flow in one direction only, protecting
equipment and system integrity.
7. What is the recommended material for underground gas piping?
Polyethylene (PE) or coated steel
PE is corrosion-resistant and flexible; coated steel is used where extra
strength is needed.
8. What safety equipment is essential when testing gas lines for
leaks?
Soap solution or electronic leak detector
These tools detect leaks safely without creating sparks or open flames.
9. How often should gas appliances be inspected for safety and
efficiency?
Annually
Regular inspections prevent malfunctions and ensure safe operation.
10. Which regulator type is commonly used for high-pressure
industrial gas systems?
Two-stage regulator
Two-stage regulators provide more accurate pressure control for systems
with varying demand.
11. What is the main hazard of propane compared to natural gas?
It is heavier than air and can accumulate in low areas
Propane can pool in basements or pits, creating a fire or explosion
hazard.
12. Which tool is used to cut copper gas tubing?
Tubing cutter
Tubing cutters provide a clean, square cut essential for proper
connections.
13. What is the purpose of venting in a gas appliance?
QUESTIONS AND CORRECT ANSWERS
1. What is the primary purpose of a pressure regulator in a gas
system?
To maintain a consistent downstream pressure
It ensures appliances receive gas at a safe and consistent pressure
regardless of fluctuations in supply.
2. Which type of gas is commonly used in residential applications for
cooking and heating?
Natural gas
Natural gas is widely available and preferred for residential use due
to its clean-burning properties.
3. What is the correct action if a gas leak is detected during
inspection?
Shut off the gas supply immediately and ventilate the area Gas
leaks are hazardous; immediate shut-off and ventilation prevent
fire or explosion risks.
4. When joining steel pipes for gas installation, which method is
standard?
Threaded connections with proper sealing compounds Threaded
joints provide mechanical strength and sealing, preventing gas
leaks.
5. What is the maximum allowable pressure for a residential natural gas
system?
1/2 psi (3.5 kPa)
Residential systems operate at low pressure; exceeding this can damage
appliances or piping.
, 6. Which device prevents gas from flowing backward in a pipeline?
Check valve
Check valves allow gas to flow in one direction only, protecting
equipment and system integrity.
7. What is the recommended material for underground gas piping?
Polyethylene (PE) or coated steel
PE is corrosion-resistant and flexible; coated steel is used where extra
strength is needed.
8. What safety equipment is essential when testing gas lines for
leaks?
Soap solution or electronic leak detector
These tools detect leaks safely without creating sparks or open flames.
9. How often should gas appliances be inspected for safety and
efficiency?
Annually
Regular inspections prevent malfunctions and ensure safe operation.
10. Which regulator type is commonly used for high-pressure
industrial gas systems?
Two-stage regulator
Two-stage regulators provide more accurate pressure control for systems
with varying demand.
11. What is the main hazard of propane compared to natural gas?
It is heavier than air and can accumulate in low areas
Propane can pool in basements or pits, creating a fire or explosion
hazard.
12. Which tool is used to cut copper gas tubing?
Tubing cutter
Tubing cutters provide a clean, square cut essential for proper
connections.
13. What is the purpose of venting in a gas appliance?
