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).
One of the many requirements for entering confined spaces is the measurement for flammable gases. Prior to entry of a confined space, the level of flammable gases must be below 10% of LEL. The most common sensor used for measuring LEL is the Wheatstone bridge/catalytic bead/pellistor sensor (Wheatstone bridge).