Taxonomy I
Taxonomy II
Taxonomy III
Taxonomies I - II - III
Taxonomies II - III
Appendix A – Units of measurement and symbols
Appendix B – Special characters
Appendix C – Standard spellings for terms with prefixes
Appendix D – Style guide development history

APPENDIX A – Units of measurement and symbols

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z 
Word or term Unit of measurement Symbol Shortcut key Comments
ampere A      
ampere-hour Ah      
American wire gauge AWG      
A-weighted decibel dBA      
British thermal unit BTU      
British thermal unit per hour Btuh      
British thermal unit per pound BTU/lb     No period after lb
bullet   • Bullet list from ICEMS toolbar
carbon dioxide  
CO₂
 Special character  
centimetre cm      
centre‑to‑centre C-C      
circular mil cmil      
cubic centimetre cm³   Special character No period after cm unless at end of sentence
  e.g. The box's volume is 100 cm³.
cubic feet per hour CFH   Special character  
cubic feet per minute CFM   Special character  
cubic foot ft³   Special character No period after ft unless at end of sentence
  e.g. The container's volume is 1 000 ft³.
cubic inch in³   Special character No period after in unless at end of sentence
  e.g. The box's volume is 100 in³.
cubic metre m³   Special character No period after m unless at end of sentence
  e.g. The tank's volume is 1 000 m³.
cubic yard yd³   Special character No period after yd unless at end of sentence
  e.g. The block measures 1 yd³.
decibel dB      
degree Celsius °C   Special character
  • Round symbol
  • 1 non‑break space before symbol
      e.g. 20 °C
degree Farenheit °F   Special character
  • Round symbol
  • 1 non‑break space before symbol
      e.g. 80 °F
degree (angle)   ° Special character
  • Round symbol
  • No space before symbol
      e.g. 45° right angle
dimensions   ×   1 non‑break space before and after symbol
  e.g. 4 m × 6 m
division   ÷   1 non‑break space before and after symbol
dollar   $   No space on either side of symbol
  e.g. $2.53, CAN$2.53
farad F      
feet per minute fpm      
feet per second fps      
feet per tooth fpt      
fixture Unit FU      
fluid ounce fl. oz.      
foot ft.      
gallon gal.     Imperial gallon by default
gallons per hour gph      
gallons per minute gpm      
gauge ga.      
gram g      
henry H      
hertz Hz      
horsepower hp      
hour hr      
inch in.      
inches per minute ipm      
inches water column in. w.c.      
inside diameter ID      
joule J      
kilogram kg      
kilohertz kHz      
kilojoule kJ      
kiloohm kΩ      
kilometres per hour km/h      
kilopascal kPa      
kilopascal gauge kPaG      
kilovolt kV      
kilovolt-ampere kVA      
kilowatt kW      
kilowatt hour KWh      
linear foot lin. ft.     Lineal is incorrect
litre L      
medium voltage alternating current MVAC      
medium voltage direct current MVDC      
metre m      
metres per second mps      
micro-   µ  
  • Equivalent to 10-6
  • Only use with metric measurements
  • No space after symbol
      e.g. 50 µm (i.e. micrometres / microns)

    NOTE: Use long form with imperial measurements
      e.g. 50 microinches
micrometre
micron 		  µm   Equivalent to 10-6
  e.g. 50 µm (i.e. micrometres / microns)
mile mi.      
miles per hour mph      
milliampere mA      
milligram mg      
millimetre mm      
million BTU per hour MMBH      
millivolt mV      
millivolt alternating current mV AC      
millivolt direct current mV DC      
minute min     Do not use symbol (') for minutes, even in trades (e.g. Machinist) that use it in diagrams
more or less   ± Special character  
multiplication   × Special character 1 non‑break space before and after symbol
newton N      
not to scale NTS      
number(s) No(s).      
ohm   Ω Special character  
on centre OC    
ounce oz.      
outside diameter OD      
parts per million ppm      
percent   %   No space before symbol
pi (3.1416)   π Special character The standard value for pi across all RS trades is 3.1416
pound lb.      
pound‑force
(unit of torque) 		lb. ft.   Special character Foot‑pound is the term used in the RS trades for torquing
pound‑force lbf      
pounds per square inch psi      
pounds per square inch absolute psia      
pounds per square inch gauge psig      
quart qt.      
revolutions per minute rpm      
second s   Special character Do not use symbol ('') for seconds, even in trades (e.g. Machinist) that use it in diagrams
seconds per rotation spr      
square centimetre cm³   Special character No period after cm unless at end of sentence
  e.g. The box measures 1 000 cm².
square foot ft²   Special character No period after ft unless at end of sentence
  e.g. The room measures 100 ft².
square inch in²   Special character No period after in unless at end of sentence
  e.g. The box measures 1 000 in².
square metre m²   Special character No period after m unless at end of sentence
  e.g. The room measures 10 m².
square yard yd²   Special character No period after yd unless at end of sentence
  e.g. The front lawn measures 100 yd².
standard cubic feet per minute SCFM      
surface feet per minute sfpm      
thousand circular mil kcmil      
teeth per inch tpi      
thousand BTU per hour MBH      
threads per inch TPI      
ton t    
  • Imperial ton or long ton
  • Equals 2 240 lb. / 1 016 kg
tonne t    
  • Metric tonne
  • Equals 2 204 lb. / 1 000 kg
tonne t    
  • American tonne or short tonne
  • Equals 2 000 lb. / 907 kg
top dead centre TDC    
US gallon USG      
US gallons per hour USGPH      
US gallons per minute USGPM      
US water gallon USWG      
volt V      
volt-ampere VA      
volts alternating current VAC      
volts direct current VDC      
volt-ohm-milliammeter VOM      
water column w.c.      
watt W      
yard yd