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Unit Modifiers

Unit Modifiers

Unit Modifiers

(OP)
When describing units of measure, should there be a space between the value and the modifier?

300 Hz
or
300Hz

Is there any standard for this?

"I think there is a world market for maybe five computers."
Thomas Watson, chairman of IBM, 1943.
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RE: Unit Modifiers

There is a space. Reference NIST Special Publication 811, Guide for the Use of the International System of Units (SI) (available at http://physics.nist.gov/cuu/pdf/sp811.pdf):

Quote:

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. (See Sec. 7.2.)

a 25 kg sphere but not : a 25-kg sphere ...

If the spelled-out name of a unit is used, the normal rules of English are applied: "a roll of 35-millimeter film." (See Sec. 7.6, note 3.)

xnuke

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RE: Unit Modifiers

Wow.  I'm surprised at the no-hyphen rule for adjectival use.  It really bothers me to see no hyphen there and I'd always assumed that was an error.

And a space before a percent sign?  Phooey!!

And the space before the degree symbol for temperature??  When they don't have a space before the degree symbol for angles?  Double phooey.

(I'll be in my trailer.  I can't work under these conditions.)

Hg

RE: Unit Modifiers

I believe the space only applies when "English" abbreviations are used (lb, kg, in, Hz, etc) ... when using symbols, the "rule" does not apply (5", 3', 50°, etc).



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RE: Unit Modifiers

Mathcad does not believe in providing any space between the numbers and the units. I think, without it, it would have been difficult for the mathcad-developers to pair the numbers with units.

So don't worry and blame it on Mathcad.

Ciao.

RE: Unit Modifiers

CorBlimeyLimey,

The rules in NIST SP 811 are only for the SI.  Therefore, lb and in are not acceptable for use and don't apply.  No space between value and unit applies ONLY to plane angle units °, ", and ', which are units outside the SI (but accepted for use with the SI) and thus less preferred.

HgTx,

When I look at NIST SP 811, I don't think the space between value and % looks bad.  Here is a test - does it look bad here on Eng-Tips?

100 % of Eng-Tips users prefer the SI.
0% of Eng-Tips users prefer something else.

The hyphen is omitted because it can be confused with the subtraction sign.  Thus, it is preferred to minimize hyphen usage when using SI (and calculations in general).

Regards,

Cory

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RE: Unit Modifiers

Minus vs. hyphen makes sense, except that would you be subtracting?  "m" from "0.23"?  I guess it could be a variable "m" though.

And yes, the space before the % looks bad on Eng Tips too.  And in the ASTM standards.  I acknowledge that this is a personal preference (born of years of this being the standard in various publications, dammit).

I'm a fan of keeping the degree symbol attached to the numbers regardless of whether it's an angle or a temperature.  It's a superscripted thingy (even though it is not a superscript letter "o") and it belongs with whatever's before it (sez me), and besides a degree sign is a degree sign.  What they've done instead is attach it to the symbol after it (C,F) to make a two-character symbol.  

Feh.

Anyway I just did some poking around, and style sheets for technical papers are all over the place, even on the issue of whether there's a space before the unit.  (I'm with the SI on that one.)

But if you must submit to The Man, at least make those spaces nonbreaking spaces.  I hate to see things like this in the ASTM books:

blah blah blah words words 7
% blah more words narrow col-
umns blah blah words words 23
mm blah blah.

Please?

Hg

RE: Unit Modifiers

If you've a large project, a good practice is to assign/agree on standards for the project.  These would include the obvious such as wordprocessing program and document formats, but could also include a writing style guide.  

When in doubt, go the chosen writing style guide.  If/when this guide isn't adequate for a specific item, make a decision, and document it so others will know what the writing requirements are.

There are MANY style guides available - just "google" on "writing style guide".

RE: Unit Modifiers

(OP)
Style guides are nice for the majority of users, but I'll base my techincal writing and reports on standards.

Personally, I hate the spaces and dashes.  Justcramitalltogether.

"I think there is a world market for maybe five computers."
Thomas Watson, chairman of IBM, 1943.
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

RE: Unit Modifiers

Style guides are standards.  For particular industries, publications, employers.

Hg

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