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).
Using methane in air as an example, the LEL of methane is 5% by volume. So an LEL Detector, working as part of a complete LEL Gas Detection System, that's calibrated to detect methane in air in a range of 0-100% LEL Methane will detect the presence of methane in air between 0-100% LEL, or 0-5% by volume.