Gas Fitter Licensing Exam Questions 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 pressure for appliances
b) To maintain a constant gas pressure regardless of demand
c) To filter impurities from gas
d) To measure gas consumption
b) To maintain a constant gas pressure regardless of demand
Regulators are designed to reduce and control the pressure of gas
supplied to appliances, ensuring safe and efficient operation.
2. What type of pipe is commonly used for natural gas distribution in
residential buildings?
a) PVC
b) Copper
c) CSST (Corrugated Stainless Steel Tubing)
d) CPVC
c) CSST (Corrugated Stainless Steel Tubing)
CSST is flexible, corrosion-resistant, and widely used for indoor gas
piping; copper is also allowed in some areas but CSST is most common
today.
3. Which gas is most commonly used in residential heating in the
U.S.?
a) Propane
, b) Natural gas
c) Butane
d) Hydrogen
b) Natural gas
Natural gas is widely distributed via pipelines and used in most
residential heating applications.
4. What is the minimum clearance required between a gas appliance
vent and combustible materials?
a) 1 inch
b) 6 inches
c) 12 inches
d) 24 inches
c) 12 inches
Most building codes require at least 12 inches clearance to prevent heat
transfer that could ignite nearby combustibles.
5. What is the correct procedure if a gas leak is detected?
a) Turn on all appliances to burn the gas
b) Evacuate the area and call the gas company
c) Seal the leak with tape
d) Ignore it if it smells faint
b) Evacuate the area and call the gas company
Natural gas is highly flammable; immediate evacuation and
professional response are required.
6. When testing for gas leaks in a new installation, which method is
safest?
a) Using a flame
, b) Using a soap solution
c) Using an electric spark
d) Using water
b) Using a soap solution
Soap solution bubbles when gas escapes, allowing safe detection
without ignition risk.
7. What is the maximum allowable working pressure for a standard
residential gas system?
a) 1 psi
b) 5 psi
c) 10 psi
d) 25 psi
a) 1 psi
Residential systems are low-pressure; exceeding 1 psi can be dangerous
and is against most codes.
8. What is the main function of a gas shutoff valve?
a) To regulate gas flow continuously
b) To completely stop gas flow for maintenance or emergencies
c) To measure gas flow
d) To vent excess pressure
b) To completely stop gas flow for maintenance or emergencies
Shutoff valves are safety devices to isolate sections of piping or
appliances.
9. Which of the following is a flammable gas used in portable
heating?
a) Methane
, b) Propane
c) Carbon dioxide
d) Nitrogen
b) Propane
Propane is commonly stored in tanks for portable or remote heating and
cooking.
10. A gas appliance requires a 3/4 inch pipe connection. What is
the proper fitting size for this appliance?
a) 1/2 inch
b) 3/4 inch
c) 1 inch
d) 1 1/4 inch
b) 3/4 inch
Pipe fittings must match the appliance inlet size to ensure proper flow
and safety.
11. What is the purpose of a venting system for a gas appliance?
a) To supply extra oxygen to the appliance
b) To remove combustion by-products safely
c) To increase heat output
d) To filter gas
b) To remove combustion by-products safely
Venting prevents dangerous gases like carbon monoxide from entering
living spaces.
12. Which tool is essential for cutting and threading black iron
pipe?
a) Hacksaw
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 pressure for appliances
b) To maintain a constant gas pressure regardless of demand
c) To filter impurities from gas
d) To measure gas consumption
b) To maintain a constant gas pressure regardless of demand
Regulators are designed to reduce and control the pressure of gas
supplied to appliances, ensuring safe and efficient operation.
2. What type of pipe is commonly used for natural gas distribution in
residential buildings?
a) PVC
b) Copper
c) CSST (Corrugated Stainless Steel Tubing)
d) CPVC
c) CSST (Corrugated Stainless Steel Tubing)
CSST is flexible, corrosion-resistant, and widely used for indoor gas
piping; copper is also allowed in some areas but CSST is most common
today.
3. Which gas is most commonly used in residential heating in the
U.S.?
a) Propane
, b) Natural gas
c) Butane
d) Hydrogen
b) Natural gas
Natural gas is widely distributed via pipelines and used in most
residential heating applications.
4. What is the minimum clearance required between a gas appliance
vent and combustible materials?
a) 1 inch
b) 6 inches
c) 12 inches
d) 24 inches
c) 12 inches
Most building codes require at least 12 inches clearance to prevent heat
transfer that could ignite nearby combustibles.
5. What is the correct procedure if a gas leak is detected?
a) Turn on all appliances to burn the gas
b) Evacuate the area and call the gas company
c) Seal the leak with tape
d) Ignore it if it smells faint
b) Evacuate the area and call the gas company
Natural gas is highly flammable; immediate evacuation and
professional response are required.
6. When testing for gas leaks in a new installation, which method is
safest?
a) Using a flame
, b) Using a soap solution
c) Using an electric spark
d) Using water
b) Using a soap solution
Soap solution bubbles when gas escapes, allowing safe detection
without ignition risk.
7. What is the maximum allowable working pressure for a standard
residential gas system?
a) 1 psi
b) 5 psi
c) 10 psi
d) 25 psi
a) 1 psi
Residential systems are low-pressure; exceeding 1 psi can be dangerous
and is against most codes.
8. What is the main function of a gas shutoff valve?
a) To regulate gas flow continuously
b) To completely stop gas flow for maintenance or emergencies
c) To measure gas flow
d) To vent excess pressure
b) To completely stop gas flow for maintenance or emergencies
Shutoff valves are safety devices to isolate sections of piping or
appliances.
9. Which of the following is a flammable gas used in portable
heating?
a) Methane
, b) Propane
c) Carbon dioxide
d) Nitrogen
b) Propane
Propane is commonly stored in tanks for portable or remote heating and
cooking.
10. A gas appliance requires a 3/4 inch pipe connection. What is
the proper fitting size for this appliance?
a) 1/2 inch
b) 3/4 inch
c) 1 inch
d) 1 1/4 inch
b) 3/4 inch
Pipe fittings must match the appliance inlet size to ensure proper flow
and safety.
11. What is the purpose of a venting system for a gas appliance?
a) To supply extra oxygen to the appliance
b) To remove combustion by-products safely
c) To increase heat output
d) To filter gas
b) To remove combustion by-products safely
Venting prevents dangerous gases like carbon monoxide from entering
living spaces.
12. Which tool is essential for cutting and threading black iron
pipe?
a) Hacksaw
