LEL monitors are used to alert personnel to a leak as a flammable condition exists.

• A. True
• B. Not always
• C. False
• D. Only in certain configurations

Answer: (C)

LEL monitors warn when the ambient concentration of a flammable gas reaches a hazardous level, expressed as a percentage of the lower explosive limit. Their job is to identify a potentially explosive atmosphere, not to specifically detect a leak. A leak is just one way a flammable atmosphere can form, but it isn’t guaranteed that a leak will reach the LEL threshold, and a flammable condition can occur from other sources as well. Because the monitor’s purpose is atmospheric gas concentration, not definitively signaling a leak, the statement isn’t universally true. That’s why the answer is false.