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).
Reference Information 443 ReferenceInformation www.mathesontrigas.com Lower and Upper Explosive Limits forFlammable Gases and Vapors (LEL/UEL) Before a fire or explosion can occur, three conditions must be metsimultaneously. A fuel (ie.combustible gas) and oxygen (air) mustexist in certain proportions, along with an ignition source, such asa spark or flame. The ratio of fuel and oxygen that is requiredvaries with each combustible gas or vapor.he maximum concentration of a gasor vapor that will burn in air is defined as the Upper ExplosiveLimit (UEL). Above this level, the mixture is too ârichâ to burn.The range between the LEL and UEL is known as the flammablerange for that gas or vapor.