Lower Explosive Limit (LEL) is what percentage?

Lower Explosive Limit (LEL) is what percentage?

• A. 16%
• B. 12%
• C. 21%
• D. 25%

Answer: (A)

Lower Explosive Limit tells you the minimum concentration of a flammable gas in air that can sustain a flame if an ignition source is present. For ammonia, that threshold is about 16 percent by volume in air. This means mixtures below roughly 16% ammonia are too lean to ignite, even with a spark, while mixtures at or above this level can ignite if there’s an ignition source and the concentration stays within the flammable range. In safety practice, we keep ammonia well below this limit with good ventilation and detectors. (The upper limit, or upper explosive limit, for ammonia is higher—around the mid-20s to 28% by volume—defining the other end of the flammable range.)

Lower Explosive Limit tells you the minimum concentration of a flammable gas in air that can sustain a flame if an ignition source is present. For ammonia, that threshold is about 16 percent by volume in air. This means mixtures below roughly 16% ammonia are too lean to ignite, even with a spark, while mixtures at or above this level can ignite if there’s an ignition source and the concentration stays within the flammable range. In safety practice, we keep ammonia well below this limit with good ventilation and detectors. (The upper limit, or upper explosive limit, for ammonia is higher—around the mid-20s to 28% by volume—defining the other end of the flammable range.)