Volume percent

Volume percent or percent by volume ( vol % Abbr, vol - % ) refers to the measure of the fraction of a substance in a mixture by volume. Differs from the density of the substance from that of the mixture, this volume fraction thus differs also from the always -ended mass fraction.

The volume percent goes back to the issue of the DIN 1310 "salary of solutions " from April 1926 and is now outdated, as it is no longer the relevant standards such as DIN 5477 " percent, per mille " of February 1983 DIN 1310 "Composition of mixed phases " of February 1984 and the ISO 31-0 Quantities and units - Part 0: General principles of the 1992 equivalent. Instead of " 35.2 volume - % " should therefore be formulated today, "The volume fraction of 35.2 %," unless that case, the concentration by volume is meant.

Common applications for the specification especially in liquid mixtures. The most prominent example is likely the alcohol content in beverages be, which is always given in volume percent. The EU Regulation 1169/2011 stipulates that drinks with an alcohol content of more than 1.2 percent by volume in general the actual alcoholic strength shall be expressed in percent by volume. The prescribed specification is " % vol". This claim may be the word 'alcohol ' or the abbreviation 'alc' prepended.

Since the alcohol itself has a relatively low density of only about 0.79 kg / l, the rest of the ingredients, however, usually one of 1.0 kg / l or more, the difference with the mass fraction is possibly significant.

Also applies the claim still in the range of gas mixtures or gas concentrations. For example, the proportion of methane in the natural gas or the explosion limits, i.e., the minimum or maximum required proportion of an explosive gas in air, " vol - % " specified.