evaporation rate

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Vaporization rate of a chemical compared with the vaporization rate of a standard chemical such as normal-butyl acetate (also written as n-Butyl Acetate, n-BuAc, or NBUAC) whose vaporization rate is standardized as 1.0. Evaporation rate is an important factor in evaluating health and fire hazard of the named chemical a fast evaporation rate generally indicates a high health, fire, and/or explosion risk. Chemicals with evaporation rate of 3.0 (three time the evaporation of normal butyl acetate), such as acetone (5.6), hexane (8.3), or methyl ethyl ketone or MEK (3.8) are classified as 'fast evaporating.' Chemicals with evaporation rate between 0.8 and 3.0, such as ethyl alcohol (1.4) or VM&P; naphtha (1.4) are classified as 'medium evaporating.' And chemicals with evaporation rate less than 0.8, such as water (0.3), mineral spirit (0.1), or xylene (0.6) are classified as 'slow evaporating.'