Â· 43 comments. in Facts. An intelligence quotient, or IQ, is a score derived from one of several standardized tests designed to assess intelligence. The abbreviation âIQâ comes from the German term Intelligenz-Quotient, originally coined by psychologist William Stern.
Lower explosive limit. Lower explosive limit (LEL): The lowest concentration (percentage) of a gas or a vapor in air capable of producing a flash of fire in presence of an ignition source (arc, flame, heat). The term is considered by many safety professionals to be the same as the lower flammable limit (LFL).
The lowest concentration of a combustible gas in mixture with air where it still can be ignited is called by Lower Explosive Limit (LEL) or Lower Flammable Limit (LFL).hen we plan to do welding work on the top of a pressure vessel containing one of the above common combustible gases, the first thing that we have to do is to measure the combustible gas concentration inside the vessel. The concentration should be lower than LEL of the combustible gas.