NIST unit rules and conventions

Paul Theodoropoulos paul at
Fri Sep 21 16:54:16 UTC 2018

On 9/21/2018 1:07 AM, Sanjeev Gupta wrote:
> Paul,
> Personally, I find 25kg, 50ppm, 3m, more readable; but that is neither 
> here nor there.

I also prefer 'conjoined' value plus unit. It's a choice, not a law, but 
I'm willing to conform to
an objective resource in high standing (NIST) if that's what they 
recommend, at least for
published technical documents.

> My concern is that the space between "25" and "kg" should be 
> non-breaking.  Else, readability suffers badly.  How do you do this in 
> asciidoc?

By non-breaking....I assume you mean some way to ensure that the value 
doesn't get separated from the unit on a line-break during conversion? I
hadn't even thought of that.

A quick search yielded this -

    Use the non-breaking space character entity reference | | (see
    the next question). You could also use the predefined |{nbsp}|
    attribute reference.

But then - would that imply that the non-breaking space would have to be 
inserted at nearly all value/unit entries, since we can't know for sure
where asciidoc may wind up doing a line break? I guess it could be 
case-by-case, if a test conversion has it happen, insert one there.

> -- 
> Sanjeev Gupta
> +65 98551208
> On Thu, Sep 20, 2018 at 3:56 AM Paul Theodoropoulos via devel 
> <devel at <mailto:devel at>> wrote:
>     NIST has a page of guidelines for formatting units in documents -
>     I am conforming unit presentation within the various documents I'm
>     editing to use the guidelines, mostly #15:
>         There is a space between the numerical value and unit symbol,
>         even when the value is used in an adjectival sense, except in
>         the case of superscript units for plane angle.
>         proper:     a 25 kg sphere
>                     an angle of 2° 3'  4"
>                     If the spelled-out name of a unit is used, the
>         normal rules of English apply: "a roll of 35-millimeter film."
>         improper:   a 25-kg sphere
>                     an angle of 2 ° 3 ' 4 "
>     So for example, where there are instances of 50ppm, 8-ms, I'm
>     updating them to 50 ppm, 8 ms.
>     Uniformity of presentation seems like a desireable goal - are
>     there any objections to following these particular guidelines?
>     There's a handful of other conventions codified that may turn up
>     needing conformance, which I'll also conform where I find them -
>     where reasonable.
>     -- 
>     Paul Theodoropoulos
>  <>
>     _______________________________________________
>     devel mailing list
>     devel at <mailto:devel at>

Paul Theodoropoulos

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