A—ampere

g—gram

Hz—hertz

J—joule

K—degree Kelvin

kg—kilogram

m—meter

m3—cubic meter

mg—milligram—10−3 gram

mm—millimeter—10−3 meter

Mg—megagram—106 gram

mol—mole

N—newton

ng—nanogram—10−9 gram

nm—nanometer—10−9 meter

Pa—pascal

s—second

V—volt

W—watt

Ω—ohm

µg—microgram—10−6 gram

Btu—British thermal unit

°C—degree Celsius (centigrade)

cal—calorie

cfm—cubic feet per minute

cu ft—cubic feet

dcf—dry cubic feet

dcm—dry cubic meter

dscf—dry cubic feet at standard conditions

dscm—dry cubic meter at standard conditions

eq—equivalent

°F—degree Fahrenheit

ft—feet

gal—gallon

gr—grain

g-eq—gram equivalent

hr—hour

in—inch

k—1,000

l—liter

lpm—liter per minute

lb—pound

meq—milliequivalent

min—minute

ml—milliliter

mol. wt.—molecular weight

ppb—parts per billion

ppm—parts per million

psia—pounds per square inch absolute

psig—pounds per square inch gage

°R—degree Rankine

scf—cubic feet at standard conditions

scfh—cubic feet per hour at standard conditions

scm—cubic meter at standard conditions

sec—second

sq ft—square feet

std—at standard conditions

CdS—cadmium sulfide

CO—carbon monoxide

CO2—carbon dioxide

HCl—hydrochloric acid

Hg—mercury

H2O—water

H2S—hydrogen sulfide

H2SO4—sulfuric acid

N2—nitrogen

NO—nitric oxide

NO2—nitrogen dioxide

NOX—nitrogen oxides

O2—oxygen

SO2—sulfur dioxide

SO3—sulfur trioxide

SOX—sulfur oxides

A.S.T.M.—American Society for Testing and Materials