Maryland Master Natural Gas Fitter
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
Pdf
1. In accordance with the International Fuel Gas Code (IFGC), what is the
primary purpose of a sediment trap installed downstream of the
appliance shutoff valve?
A. To regulate manifold pressure
B. To collect moisture and debris before gas enters the appliance
C. To prevent reverse gas flow
D. To increase gas velocity in the piping system
B. To collect moisture and debris before gas enters the appliance
Rationale: Sediment traps are designed to capture condensate, dirt, scale,
and debris that may be present in the gas piping system before these
contaminants enter and damage burners, controls, or valves within gas-
fired appliances.
, 2. Which type of gas piping material is prohibited from being installed in
contact with the earth unless specifically approved for burial?
A. Corrugated stainless steel tubing (CSST)
B. Black steel pipe
C. Copper tubing
D. Galvanized steel pipe
A. Corrugated stainless steel tubing (CSST)
Rationale: Standard CSST is generally prohibited from direct burial unless it
is specifically listed and protected for underground installation because soil
conditions can damage the tubing and its jacket.
3. What is the minimum required test pressure for a low-pressure
residential natural gas piping system according to common code
standards?
A. 3 psi for 10 minutes
B. 10 psi for 15 minutes
C. 15 psi for 30 minutes
D. Operating pressure only
B. 10 psi for 15 minutes
Rationale: Residential low-pressure gas piping systems are commonly
required to be pressure tested at no less than 10 psi for at least 15 minutes
to verify the integrity of the installation before operation.
4. A natural gas fitter discovers a gas leak using a combustible gas
detector. What is the first required action?
A. Tighten all nearby fittings immediately
B. Continue appliance startup to verify operation
C. Eliminate ignition sources and secure the area
D. Purge the line with compressed air
C. Eliminate ignition sources and secure the area
,Rationale: Gas leaks present an immediate fire and explosion hazard. The
first priority is to prevent ignition by eliminating sparks, flames, and unsafe
electrical operation while securing the affected area.
5. Which component reduces high utility gas pressure to the lower
pressure required by residential appliances?
A. Sediment trap
B. Appliance connector
C. Gas regulator
D. Drip leg
C. Gas regulator
Rationale: Gas regulators reduce incoming utility gas pressure to a stable
and safe pressure level suitable for appliance operation, typically
measured in inches of water column.
6. What is the primary hazard associated with inadequate combustion air
for a gas-fired appliance?
A. Excessive gas pressure
B. Carbon monoxide production
C. High manifold temperature
D. Increased gas odorization
B. Carbon monoxide production
Rationale: Insufficient combustion air can result in incomplete combustion,
producing dangerous levels of carbon monoxide, a colorless and potentially
fatal gas.
7. Which instrument is most appropriate for measuring appliance
manifold pressure?
A. Clamp ammeter
B. Megohmmeter
, C. Manometer
D. Refrigerant gauge
C. Manometer
Rationale: A manometer is specifically designed to measure low gas
pressures accurately, including manifold and inlet pressures in gas
appliance systems.
8. What is the purpose of odorizing natural gas?
A. To improve combustion efficiency
B. To reduce corrosion in piping
C. To make gas leaks detectable by smell
D. To increase heating value
C. To make gas leaks detectable by smell
Rationale: Natural gas is naturally odorless, so odorants such as
mercaptan are added to help occupants identify leaks through smell before
dangerous concentrations develop.
9. Which of the following is considered an approved method for joining
black steel gas pipe?
A. Soldering
B. Brazing with copper alloy
C. Threaded fittings
D. Solvent cementing
C. Threaded fittings
Rationale: Black steel gas piping is commonly joined using threaded fittings
designed and listed for fuel gas applications.
10. During a gas pressure test, why must appliance regulators often
be disconnected or isolated?
A. They can become magnetized
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. In accordance with the International Fuel Gas Code (IFGC), what is the
primary purpose of a sediment trap installed downstream of the
appliance shutoff valve?
A. To regulate manifold pressure
B. To collect moisture and debris before gas enters the appliance
C. To prevent reverse gas flow
D. To increase gas velocity in the piping system
B. To collect moisture and debris before gas enters the appliance
Rationale: Sediment traps are designed to capture condensate, dirt, scale,
and debris that may be present in the gas piping system before these
contaminants enter and damage burners, controls, or valves within gas-
fired appliances.
, 2. Which type of gas piping material is prohibited from being installed in
contact with the earth unless specifically approved for burial?
A. Corrugated stainless steel tubing (CSST)
B. Black steel pipe
C. Copper tubing
D. Galvanized steel pipe
A. Corrugated stainless steel tubing (CSST)
Rationale: Standard CSST is generally prohibited from direct burial unless it
is specifically listed and protected for underground installation because soil
conditions can damage the tubing and its jacket.
3. What is the minimum required test pressure for a low-pressure
residential natural gas piping system according to common code
standards?
A. 3 psi for 10 minutes
B. 10 psi for 15 minutes
C. 15 psi for 30 minutes
D. Operating pressure only
B. 10 psi for 15 minutes
Rationale: Residential low-pressure gas piping systems are commonly
required to be pressure tested at no less than 10 psi for at least 15 minutes
to verify the integrity of the installation before operation.
4. A natural gas fitter discovers a gas leak using a combustible gas
detector. What is the first required action?
A. Tighten all nearby fittings immediately
B. Continue appliance startup to verify operation
C. Eliminate ignition sources and secure the area
D. Purge the line with compressed air
C. Eliminate ignition sources and secure the area
,Rationale: Gas leaks present an immediate fire and explosion hazard. The
first priority is to prevent ignition by eliminating sparks, flames, and unsafe
electrical operation while securing the affected area.
5. Which component reduces high utility gas pressure to the lower
pressure required by residential appliances?
A. Sediment trap
B. Appliance connector
C. Gas regulator
D. Drip leg
C. Gas regulator
Rationale: Gas regulators reduce incoming utility gas pressure to a stable
and safe pressure level suitable for appliance operation, typically
measured in inches of water column.
6. What is the primary hazard associated with inadequate combustion air
for a gas-fired appliance?
A. Excessive gas pressure
B. Carbon monoxide production
C. High manifold temperature
D. Increased gas odorization
B. Carbon monoxide production
Rationale: Insufficient combustion air can result in incomplete combustion,
producing dangerous levels of carbon monoxide, a colorless and potentially
fatal gas.
7. Which instrument is most appropriate for measuring appliance
manifold pressure?
A. Clamp ammeter
B. Megohmmeter
, C. Manometer
D. Refrigerant gauge
C. Manometer
Rationale: A manometer is specifically designed to measure low gas
pressures accurately, including manifold and inlet pressures in gas
appliance systems.
8. What is the purpose of odorizing natural gas?
A. To improve combustion efficiency
B. To reduce corrosion in piping
C. To make gas leaks detectable by smell
D. To increase heating value
C. To make gas leaks detectable by smell
Rationale: Natural gas is naturally odorless, so odorants such as
mercaptan are added to help occupants identify leaks through smell before
dangerous concentrations develop.
9. Which of the following is considered an approved method for joining
black steel gas pipe?
A. Soldering
B. Brazing with copper alloy
C. Threaded fittings
D. Solvent cementing
C. Threaded fittings
Rationale: Black steel gas piping is commonly joined using threaded fittings
designed and listed for fuel gas applications.
10. During a gas pressure test, why must appliance regulators often
be disconnected or isolated?
A. They can become magnetized
