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).
This is called the Lower Explosive Limit (LEL) of that gas or vapor. It is sometimes called the Lower Flammable Limit (LFL). The LEL is different for every gas. For most CHCs, this minimum concentration varies from about 0.5% to about 15% by volume in air. This concentration represents 100% on the Delphian system. Some combustible gases are lighter than air, some are heavier.