Environment, health and safety

What does the lower explosive limit (LEL) of a flammable gas mean?

  1. AThe maximum temperature at which the gas burns
  2. BThe lowest concentration in air at which the gas can burn or explode
  3. CThe maximum pressure of the gas container
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Answer: B. The lowest concentration in air at which the gas can burn or explode

Flammable gases burn or explode only within a certain range of concentrations in air (the explosive range). The lower end of that range is the lower explosive limit (LEL). Flammable gas detectors display concentration as a percentage of LEL and are set to alarm at concentrations well below the LEL.

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