GAS FITTER LICENSING EXAM QUESTION
AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. What is the primary purpose of a gas pressure regulator?
A. To increase gas flow
B. To reduce gas pressure to a usable level
C. To filter gas impurities
D. To measure gas volume
Correct answer reduces incoming gas pressure to a safe, usable level for
appliances.
2. Natural gas is primarily composed of:
A. Propane
B. Butane
C. Methane
D. Ethane
Methane is the main component of natural gas.
3. The maximum allowable working pressure for low-pressure residential gas
piping is:
A. 5 psi
B. 2 psi
C. 10 psi
D. 15 psi
Residential systems typically operate at 2 psi or less.
4. Gas meter installations must be:
A. Inside bedrooms
B. Accessible for reading and maintenance
C. Behind locked doors
, D. In attics
Meters must be accessible for service and readings.
5. A pressure test on a gas line after installation must be maintained for how
long?
A. 5 minutes
B. 10 minutes
C. 30 seconds
D. 1 minute
Standard minimum duration to verify system integrity.
6. A common test pressure for commercial gas piping is:
A. 5 psi
B. 10 psi
C. 2 psi
D. 25 psi
Higher pressure for commercial systems during testing.
7. Combustion air for gas appliances must be:
A. Sealed from the outdoors
B. Filtered only
C. Sufficient for complete combustion and ventilation
D. Used for cooling only
Proper air supply is critical for safe combustion.
8. A yellow flame on a gas burner indicates:
A. Complete combustion
B. Incomplete combustion
C. Too much air
D. Normal operation
Yellow indicates soot and incomplete combustion.
9. Gas piping should be supported every:
A. 10 feet
B. 6 feet
C. 2 feet
D. 3 feet
Supports prevent sag and stress on joints.
, 10.CSST refers to:
A. Copper Self-Sealing Tube
B. Corrugated Stainless Steel Tubing
C. Certified Steel Seam Tube
D. Cold Seated Steel Tube
CSST is flexible stainless steel gas tubing.
11.A venting system must:
A. Be smaller than the flue collar
B. Safely exhaust combustion by-products outdoors
C. Recirculate air indoors
D. Be sealed airtight
Venting removes harmful combustion gases.
12.A “dead leg” in gas piping is:
A. A required branch
B. An unused section of pipe that traps gas
C. A measuring tool
D. A regulator type
Dead legs can trap gas and cause hazards.
13.Gas appliance connectors should be replaced every:
A. 1 year
B. 5 years
C. 10 years
D. 20 years
Regular replacement prevents leaks and failures.
14.Gas odorant added to natural gas is:
A. Ethylene
B. Mercaptan
C. Propane
D. Helium
Mercaptan gives gas a detectable smell for safety.
15.In gas fitting, “BTU” stands for:
A. Basic Thermal Unit
B. British Thermal Unit
AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A
INSTANT DOWNLOAD PDF
1. What is the primary purpose of a gas pressure regulator?
A. To increase gas flow
B. To reduce gas pressure to a usable level
C. To filter gas impurities
D. To measure gas volume
Correct answer reduces incoming gas pressure to a safe, usable level for
appliances.
2. Natural gas is primarily composed of:
A. Propane
B. Butane
C. Methane
D. Ethane
Methane is the main component of natural gas.
3. The maximum allowable working pressure for low-pressure residential gas
piping is:
A. 5 psi
B. 2 psi
C. 10 psi
D. 15 psi
Residential systems typically operate at 2 psi or less.
4. Gas meter installations must be:
A. Inside bedrooms
B. Accessible for reading and maintenance
C. Behind locked doors
, D. In attics
Meters must be accessible for service and readings.
5. A pressure test on a gas line after installation must be maintained for how
long?
A. 5 minutes
B. 10 minutes
C. 30 seconds
D. 1 minute
Standard minimum duration to verify system integrity.
6. A common test pressure for commercial gas piping is:
A. 5 psi
B. 10 psi
C. 2 psi
D. 25 psi
Higher pressure for commercial systems during testing.
7. Combustion air for gas appliances must be:
A. Sealed from the outdoors
B. Filtered only
C. Sufficient for complete combustion and ventilation
D. Used for cooling only
Proper air supply is critical for safe combustion.
8. A yellow flame on a gas burner indicates:
A. Complete combustion
B. Incomplete combustion
C. Too much air
D. Normal operation
Yellow indicates soot and incomplete combustion.
9. Gas piping should be supported every:
A. 10 feet
B. 6 feet
C. 2 feet
D. 3 feet
Supports prevent sag and stress on joints.
, 10.CSST refers to:
A. Copper Self-Sealing Tube
B. Corrugated Stainless Steel Tubing
C. Certified Steel Seam Tube
D. Cold Seated Steel Tube
CSST is flexible stainless steel gas tubing.
11.A venting system must:
A. Be smaller than the flue collar
B. Safely exhaust combustion by-products outdoors
C. Recirculate air indoors
D. Be sealed airtight
Venting removes harmful combustion gases.
12.A “dead leg” in gas piping is:
A. A required branch
B. An unused section of pipe that traps gas
C. A measuring tool
D. A regulator type
Dead legs can trap gas and cause hazards.
13.Gas appliance connectors should be replaced every:
A. 1 year
B. 5 years
C. 10 years
D. 20 years
Regular replacement prevents leaks and failures.
14.Gas odorant added to natural gas is:
A. Ethylene
B. Mercaptan
C. Propane
D. Helium
Mercaptan gives gas a detectable smell for safety.
15.In gas fitting, “BTU” stands for:
A. Basic Thermal Unit
B. British Thermal Unit
