A unit of mass for gases equal to the mass of 1 liter (0.035 3147 ft3) at a pressure of 1 atmosphere and at a standard temperature, often 0 0C (32 0F) or 20 0C (68 0F). Air flow is often stated in normal liters per minute (Nl/min)
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}