What is the lower and higher explosive level for gas?

What is the lower and higher explosive level for gas?

• A. 5%/15%
• B. 1%/5%
• C. 10%/20%
• D. 3%/8%

Answer: (A)

Gas in air can ignite only within a specific concentration range, defined by the lower explosive limit (LEL) and the upper explosive limit (UEL). Below the LEL there isn’t enough gas to sustain combustion, and above the UEL there isn’t enough oxygen for ignition. For natural gas (primarily methane), this flammable range is about 5% to 15% by volume in air. So the lower explosive level is 5% and the higher explosive level is 15%.

Gas in air can ignite only within a specific concentration range, defined by the lower explosive limit (LEL) and the upper explosive limit (UEL). Below the LEL there isn’t enough gas to sustain combustion, and above the UEL there isn’t enough oxygen for ignition. For natural gas (primarily methane), this flammable range is about 5% to 15% by volume in air. So the lower explosive level is 5% and the higher explosive level is 15%.