Historical
IEC 80416-1 Ed. 1.0 b:2001
Basic principles for graphical symbols for use on equipment - Part 1: Creation of symbol originals
This Part 1 of the standard specifies the key principles for the creation of symbol originals for use on equipment. In accordance with the intended meaning of the symbol originals, it contains rules for design such as shape and size, and also for preparation of the accompanying texts.
International Electrotechnical Commission [iec]