What is the flammability range of methane as it relates to CNG?

• A. 1 to 3 %
• B. 5 to 15 %
• C. 10 to 20 %
• D. 3 to 6 %

Answer: (B)

The flammability range of methane, particularly concerning compressed natural gas (CNG), is specifically recognized as being between 5% to 15% in air. This range indicates the concentration of methane in the air that is capable of sustaining combustion; if the concentration is below 5%, the mixture is too lean to ignite, and if it's above 15%, it is too rich to burn. Understanding this range is crucial for safety and management in environments where CNG is used, as it helps inform safe handling practices, storage, and potential ignition risks.