Tanker Familiarization Liquefied Natural Gas (LNG) Practice Exam

If the flammable range for LNG is above 15% range, what does this mean?

Too lean to burn Too rich to burn It can burn at any concentration It is non-flammable

Correct Answer:

Too rich to burn

Explanation:

The concept here is the flammable range, which is the range of vapor concentrations in air that can sustain combustion. For LNG (primarily methane), that range is roughly from 5% to 15% by volume in air. If the concentration is above the upper limit—about 15%—the mixture is too rich to burn because there isn’t enough oxygen to support the flame. So, a vapor cloud with LNG concentration higher than 15% won’t ignite or sustain combustion. The other options describe concentrations outside the range differently (too lean would be below the lower limit; being able to burn at any concentration isn’t true; non-flammable is too vague).

Access more questions from this quiz

Continue to Tanker Familiarization Liquefied Natural Gas (LNG) Practice Exam for more practice questions and the full quiz experience.

Access More Questions