Gas Fitter Licensing Exam based on general
U.S. gas fitter standards including NFPA 54
(National Fuel Gas Code) Exam Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the maximum allowable pressure for a residential natural
gas system downstream of the regulator?
a) 5 psi
b) 1 psi
c) 0.5 psi
d) 2 psi
Correct answer ensures safety and compliance with NFPA 54
residential pressure limits.
2. Which type of gas pipe is commonly used for underground natural
gas service?
a) Copper
b) PE (polyethylene) plastic
c) Galvanized steel
d) PVC
PE plastic is corrosion-resistant and approved for underground gas
service.
3. What is the minimum clearance required between a gas meter
and a window opening?
, a) 6 inches
b) 12 inches
c) 18 inches
d) 24 inches
Maintaining minimum clearance prevents gas from entering the
building through openings.
4. What is the primary purpose of a gas pressure regulator?
a) Increase gas pressure
b) Maintain consistent gas pressure
c) Filter impurities
d) Measure gas flow
A regulator ensures appliances receive gas at safe operating
pressures.
5. Which fitting is required for connecting a flexible gas connector to
an appliance?
a) Slip joint
b) Threaded brass connector
c) Compression copper fitting
d) PVC adapter
Threaded brass fittings provide secure, leak-free connections for
flexible gas lines.
6. What is the minimum allowable burial depth for underground gas
piping in a residential yard?
a) 6 inches
b) 12 inches
c) 18 inches
d) 24 inches
, NFPA 54 requires 18-inch minimum cover for safety and
protection.
7. Which of the following is an approved method for testing gas
piping for leaks?
a) Open flame
b) Soap solution
c) Water only
d) Visual inspection only
Soap solution bubbles indicate leaks safely without ignition risk.
8. A natural gas appliance requires 1.0 inch WC (water column) of
pressure. The regulator is set to 2.0 inch WC. What is the effect?
a) Appliance will operate normally
b) Appliance may have incomplete combustion or flame issues
c) Gas flow will stop
d) Appliance will shut off automatically
Overpressure can cause yellow flames, soot, or unsafe operation.
9. What is the primary fuel for most residential gas appliances?
a) Propane
b) Butane
c) Natural gas
d) Hydrogen
Natural gas is the most common residential fuel in the U.S.
10. Which of the following is a flexible appliance connector
made of stainless steel?
a) PVC tubing
b) Corrugated stainless steel tubing (CSST)
c) Black iron pipe
U.S. gas fitter standards including NFPA 54
(National Fuel Gas Code) Exam Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the maximum allowable pressure for a residential natural
gas system downstream of the regulator?
a) 5 psi
b) 1 psi
c) 0.5 psi
d) 2 psi
Correct answer ensures safety and compliance with NFPA 54
residential pressure limits.
2. Which type of gas pipe is commonly used for underground natural
gas service?
a) Copper
b) PE (polyethylene) plastic
c) Galvanized steel
d) PVC
PE plastic is corrosion-resistant and approved for underground gas
service.
3. What is the minimum clearance required between a gas meter
and a window opening?
, a) 6 inches
b) 12 inches
c) 18 inches
d) 24 inches
Maintaining minimum clearance prevents gas from entering the
building through openings.
4. What is the primary purpose of a gas pressure regulator?
a) Increase gas pressure
b) Maintain consistent gas pressure
c) Filter impurities
d) Measure gas flow
A regulator ensures appliances receive gas at safe operating
pressures.
5. Which fitting is required for connecting a flexible gas connector to
an appliance?
a) Slip joint
b) Threaded brass connector
c) Compression copper fitting
d) PVC adapter
Threaded brass fittings provide secure, leak-free connections for
flexible gas lines.
6. What is the minimum allowable burial depth for underground gas
piping in a residential yard?
a) 6 inches
b) 12 inches
c) 18 inches
d) 24 inches
, NFPA 54 requires 18-inch minimum cover for safety and
protection.
7. Which of the following is an approved method for testing gas
piping for leaks?
a) Open flame
b) Soap solution
c) Water only
d) Visual inspection only
Soap solution bubbles indicate leaks safely without ignition risk.
8. A natural gas appliance requires 1.0 inch WC (water column) of
pressure. The regulator is set to 2.0 inch WC. What is the effect?
a) Appliance will operate normally
b) Appliance may have incomplete combustion or flame issues
c) Gas flow will stop
d) Appliance will shut off automatically
Overpressure can cause yellow flames, soot, or unsafe operation.
9. What is the primary fuel for most residential gas appliances?
a) Propane
b) Butane
c) Natural gas
d) Hydrogen
Natural gas is the most common residential fuel in the U.S.
10. Which of the following is a flexible appliance connector
made of stainless steel?
a) PVC tubing
b) Corrugated stainless steel tubing (CSST)
c) Black iron pipe
