G3 Properties of Fuel Gases 3

Question 1

What happens to natural gas volume when temperature increases at constant pressure?

Accepted Answer

Volume increases proportionally (Charles's Law)

Answer

Volume decreases

Answer

Volume stays unchanged

Answer

Volume doubles per degree

Question 2

Why does natural gas heating value vary between supply regions?

Accepted Answer

Composition varies by source with different hydrocarbon proportions

Answer

Utilities artificially adjust it

Answer

Temperature differences cause variation

Answer

Pipe material affects it during transport

Question 3

What is flame rectification in gas appliances?

Accepted Answer

Proving flame presence by detecting electrical conductivity of a flame

Answer

Adjusting flame colour

Answer

Straightening bent burners

Answer

Purifying gas before combustion

Question 4

How does propane's flue gas dew point compare to natural gas?

Accepted Answer

Propane has a higher dew point (~59°C) than natural gas (~54°C)

Answer

Propane has a lower dew point

Answer

Both have identical dew points

Answer

Propane produces no water vapour

Question 5

How does altitude affect gas appliance performance?

Accepted Answer

Higher altitude means less oxygen, requiring derating

Answer

Altitude has no effect

Answer

Higher altitude increases output

Answer

Only affects electric appliances

Question 6

How do flammability limits relate to gas leak safety?

Accepted Answer

Understanding limits helps determine safe ventilation rates and detector alarm setpoints

Answer

Leaks are only dangerous inside the flammable range

Answer

Limits only apply to confined spaces

Answer

Leaks below LEL are completely safe