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).
1993-1994 ACGIH TLV: Simple asphyxiant. Description of substance: Colorless, odorless gas. LEL: . . 2.1% (10% LEL, 2,100 ppm). Original (SCP) IDLH: 20,000 ppm [LEL]. Basis for original (SCP) IDLH: Propane is a simple asphyxiant and does not present an IDLH hazard at concentrations below its lower explosive limit (LEL).The chosen IDLH is based on the LEL of 21,000 ppm rounded down to 20,000 ppm.993-1994 ACGIH TLV: Simple asphyxiant. Description of substance: Colorless, odorless gas. LEL: . . 2.1% (10% LEL, 2,100 ppm). Original (SCP) IDLH: 20,000 ppm [LEL]. Basis for original (SCP) IDLH: Propane is a simple asphyxiant and does not present an IDLH hazard at concentrations below its lower explosive limit (LEL).