B NFPA 54 ANSI Z223.1

Industrial Gas Fitter Licensing Exam Class A Practice Exam 100 Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What standard primarily governs industrial gas installation safety in

North America?

A) NFPA 70

B) NFPA 54 / ANSI Z223.1

C) CSA B139

D) API 650

Rationale: NFPA 54 regulates fuel gas installation safety nationwide.

• The maximum allowed pressure drop for industrial natural gas piping

during testing typically is:

• 10% over 1 hour
• Zero pressure loss over test duration 1 / 3

• 1 psi per hour
• 5% per hour

Rationale: Any drop indicates a leak; code requires no measurable

loss.

3. An industrial gas burner lockout condition requires:

• Technician acknowledgement only
• Automatic restart
• Manual reset
• Continuous purge

Rationale: Manual reset ensures safe assessment before re-ignition.

4. Propane vapor pressure increases with:

• Decrease in temperature
• Increase in temperature
• Gas line length
• Regulator age

Rationale: Heat adds energy to the liquid → higher vapor pressure.

• What device prevents backflow of combustion products into the fuel

line?

• Manual gas cock
• Filter
• Check valve / backflow preventer
• Flame rod

Rationale: Ensures one-directional flow toward the appliance. 2 / 3

6. Lower Explosive Limit (LEL) for natural gas ≈:

A) 0.5%

• 5%

C) 25%

D) 50%

Rationale: Mixtures above 5% natural gas become explosive.

• When purging an industrial gas pipeline, which gas is preferred?
• Oxygen
• Steam
• Nitrogen
• Carbon monoxide

Rationale: Nitrogen is inert and safe for displacement.

• Which burner control confirms flame presence?
• Pressure switch
• Flame safeguard system
• Solenoid valve
• Ignition transformer

Rationale: Ensures continued safe combustion.

9. Industrial piping underground requires:

• Galvanized steel
• Aluminum
• Cathodic protection if metallic
• / 3