The IEEE and ASTM* issue joint standards for topics that concern members of both organisations. One of these is metrication. Their new standard for metrication is IEEE/ASTM SI 10-2010, American National Standard for Metric Practice (replacing SI-10 2002).

What was previously "soft" conversion, just changing from an American measure to a metric one, is now just called conversion. An example of conversion would be re-labelling a one pound packet of coffee as 454 grams.

"Hard" conversion is now called substitution. "Hard" conversion means using a metric size or product to replace the US size. An example of this would be specifying a walkway to be one metre wide, where it was previously three feet, or introducing a 500 gram packet of coffee to replace the old one pound size.

Does this change improve anyone's understanding of metrication, or is it tinkering around the edges?

Source: A letter by Howard Ressel in the USMA mailing list.

\*IEEE – Institute of Electrical and Electronic Engineers; ASTM American Society for Testing and Materials