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Journeyman Gas Fitter Licensing Exam Practice 100 Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf
- What is the primary component of natural gas used in fuel-burning
appliances?
a) Propane
b) Carbon dioxide
c) Methane
d) Nitrogen
Methane is the major constituent of natural gas, typically 90% or greater.
- The normal pressure of natural gas delivered to a residential appliance
manifold is approximately: 1 / 3
- 14” w.c.
- 3.5” w.c.
- 7” w.c.
- 1 psi
- Which standard governs gas installation codes in North America?
Most residential natural gas appliances operate at 3.5 inches water column.
a) ISO 9001
b) ASME B31.3
c) NFPA 54 / CSA B149
d) IEEE 1584
The National Fuel Gas Code (NFPA 54) / CSA B149 is the primary gas installation standard.
4. Propane vapor is:
a) Lighter than air
b) Heavier than air
c) Same density as air
d) Odorless and weightless
Propane vapor collects in low areas because it is heavier than air.
5. Ferrous gas piping should be joined using:
a) Brazing
b) PVC solvent cement
c) Threading 2 / 3
d) Hot melt adhesive
Black iron pipes are typically threaded for gas installations.
6. A yellow gas flame with black soot indicates:
a) Proper combustion
b) Incomplete combustion
c) Excess primary air
d) High gas pressure
Yellow sooty flames occur when there is insufficient air mixing.
- Which device prevents backflow of combustion gases into living
spaces?
a) Gas shutoff valve
b) Tee fitting
c) Draft hood
d) Orifice pilot
Draft hoods stabilize draft and prevent flue gas spillage.
8. The purpose of an appliance regulator is to:
a) Shut off gas supply
b) Maintain constant manifold pressure
c) Increase gas pressure
d) Filter contaminants
Regulators control outlet pressure to ensure proper combustion.
9. Before repairing a gas line, a technician must:
a) Increase gas pressure
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