G3 Properties of Fuel Gases 2

Question 1

What is the ignition temperature of natural gas?

Accepted Answer

593°C (1,100°F)

Answer

Natural gas ignites at approximately 593°C (1,100°F).

Question 2

How does propane's specific gravity differ from natural gas?

Accepted Answer

Propane is heavier than air (SG ~1.52); natural gas is lighter (SG ~0.60)

Answer

Propane sinks (SG ~1.52); natural gas rises (SG ~0.60).

Question 3

What is propane's heating value compared to natural gas?

Accepted Answer

Propane has approximately 2.5 times the value per cubic foot

Answer

Propane delivers about 2,520 BTU/ft³ versus natural gas at about 1,000 BTU/ft³.

Question 4

What is the flammable range of propane in air?

Accepted Answer

2.1% to 9.5%

Answer

Propane's flammable range is approximately 2.1% to 9.5%.

Question 5

What determines flame speed and why does it matter?

Accepted Answer

Rate a flame front travels through gas-air mixture; affects burner design

Answer

Flame speed affects burner port sizing and flame stability.

G3 - Gas Technician Level 3 Certification Practice Test