Thursday, May 11, 2017

L or l? The Ucum Liter code

Filed under stupid stuff I know.

The code for Liter in UCUM Case Sensitive is both l and L.  You can use either.

See http://unitsofmeasure.org/ucum.html#section-Derived-Unit-Atoms for details.  Basically what they say:
In the case sensitive variant the liter is defined both with an upper case ‘L” and a lower case ‘l’. NIST [63 FR 40338] declares the upper case ‘L’ as the prefered symbol for the U.S., while in many other countries the lower case ‘l’ is used. In fact the lower case ‘l’ was in effect since 1879. A hundred years later in 1979 the 16th CGPM decided to adopt the upper case ‘L’ as a second symbol for the liter. In the case insensitive variant there is only one symbol defined since there is no difference between upper case ‘L’ and lower case ‘l’.
So much for using codes to define distinct meanings for atoms of this vocabulary.  Ah well.  At least they defined L in terms of l.

   Keith