One of our readers has drawn attention to the recent issue for a comment of a revised edition of the SI brochure.
“The draft 9th edition of the SI brochure is available at:
Some of you may also be interested in BIPM committee minutes at:
Changes of interest to me include:
* Version 8 describes many non-SI units, organised in four tables (tables 6,7,8, and 9). Version 9 describes fewer non-SI units, all listed in one table (table 8).
* Both version 8 and version 9 have a table of ‘non-SI units accepted for use with …’ However, the number of units in the table has increased from nine to fifteen. This is an increase in explicit status for those particular units.
In both versions 8 and 9, I noticed a comment against the tonne, ‘In English speaking countries this unit is usually called metric ton‘. I believe this to be false. In the UK, I don’t think I ever hear or read it called that. If it’s not too late, we may have an opportunity to challenge that statement.”