Avoiding the use of prefixes for units in the denominator is fairly
common as a "style" (as opposed to a requirement) but that's not a rigid
guideline. As we've discussed, there are many reasons one might use
prefixed units in a denominator which "override" that style.
My view of the SI is that it is designed to be as flexible as possible.
The limited number of "requirements" exist only to prevent ambiguities
and to provide formatting consistent with its underlying quantity calculus.
A common fault of some new adherents to the SI, in my opinion, is to
impose rigidity that was not written in to the standard, namely the SI
Brochure. That has led, on this list, to what I consider silly
arguments, such as the pronunciation of kilometer and derogation of the
four "small" prefixes between kilo and milli.
I think that we should keep in mind that the SI's primary purpose is to
facilitate commerce (Treaty of the Meter) and that is done by clearly,
simply, reliably, and unambiguously presenting the values of quantities.
Science provides the technical realizations to cover "reliably" and the
quantity calculus covers the rest of those attributes. That's a gross
generalization but it makes a pretty picture in my mind.
Jim
On 2015-03-15 18:52, Pierre Abbat wrote:
On Wednesday, February 11, 2015 20:31:08 James wrote:
Strangely, Chapter 5 of the SI Brochure is silent on that, Pierre. At
least, I could find nothing on the matter. When you describe this
"proper" style, which standard are you using for your reference? Would
you please provide a quote of its statement to that effect and it's
clause or section number?
I don't remember the reference; it was something I picked up when studying for
the CMS test. One doesn't put milliseconds or kiloseconds in the denominator,
but one does put kilograms, because the kilogram is a base unit.
Pierre
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