Exam Questions and CORRECT Answers
7. What is the ignition temperature of natural gas?
A) 1020 F
B) 1000F
C) 1300 F
D) 900 F - CORRECT ANSWER - A) 1300°F
Explanation: Natural gas has an ignition temperature of around 1020°F. This is the temperature
at which it will ignite in the presence of oxygen.
8. What is the flame temperature of natural gas?
A) 1000F
B) 2025 F
C) 3500F
D) 3600 F - CORRECT ANSWER - C) 3600°F
Explanation: When burned, natural gas can reach flame temperatures up to approximately
3500°F.
11. What is the heating value of natural gas?
A) 2025 BTU
B) 1200 BTU
C) 3500 BTU
D) 1000 BTU - CORRECT ANSWER - D) 1000 BTU
Explanation: The typical heating value of natural gas is approximately 1000 BTUs per cubic
foot.
3. What is the relief pressure of a propane tank?
A) 250 Psig
, B) 275 Psig
C) 350 Psig
D) 375 Psig - CORRECT ANSWER - A) 375 Psig
Explanation: Propane tanks are commonly set with a relief pressure around 250 psi, which
prevents excessive pressure buildup within the tank.
16. What are the products of complete combustion?
A) Carbon dioxide, nitrogen, soot, heat
B) Heat, water, hydrogen, oxygen
C) Water, carbon dioxide, oxygen, dioxide
D) Carbon dioxide, water, heat - CORRECT ANSWER - D) Carbon dioxide, water, heat
Explanation: Complete combustion of hydrocarbons like natural gas produces carbon dioxide,
water, and heat as the main byproducts.
18. What is the air needed to operate a gas appliance safely?
A) Primary air, mixing air, free air
B) Combustion air, excess air, dilution air
C) Secondary air, primary air, natural air
D) Venting air, oxygen, excess air - CORRECT ANSWER - B) Combustion air, excess
air, dilution air
Explanation: Safe operation of gas appliances requires combustion air (for burning fuel), excess
air (to ensure complete combustion), and dilution air (to mix with exhaust gases and reduce flue
temperature).
25. Dilution air is:
A) Air to cool hot flue gases
B) Air to needed for excess air
C) Air to start combustion
D) Air to ensure flame - CORRECT ANSWER - A) Air to cool hot flue gases