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).
Combustible gas-air mixtures can be burned over a wide range of concentrations. The actual minimum concentration varies from about 0.5% to about 15% by volume in air for most common CHCs. This concentration is always referred to as 100% LEL or LFL for that gas.e sure the characteristics of the gas are known before attempting to monitor it or enter an area containing the gas. Typical alarm settings are: Low alarm = 20% LEL, High alarm = 40% LEL, High-High alarm = 60% LEL. Only the user can judge whether these settings are appropriate.