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Abbreviations and Symbols




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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 Other


Symbol Definition
Å Angstrom(s)
AA Atomic Absorption
abs absolute
ACGIH American Conference of Governmental Industrial Hygienists
ASTM American Society for Testing Materials
atm atmosphere(s)
avg average
Bar Bureau of Automotive Repair
bar Unit of pressure equal to 100,000 pascals
bp boiling point
Btu British thermal unit(s)
CAA Clean Air Act
cal calorie(s)
CAS Chemical Abstract Services
ccm cubic centimeter(s) per minute
ccs cubic centimeter(s) per second
CEM Continuous Emission Monitor
cf cubic feet
CFCs Chlorofluorocarbons
CFR Code of Federal Regulations
CGA Compressed Gas Association
cm centimeter(s)
cm2 square centimeter
cm3, cc cubic centimeter
COA Certificate of Analysis
COC Certificate of Conformance
CP Chemically Pure
Cp specific heat at constant pressure
Cv specific heat at constant volume
Cv coefficient of flow
°C degree(s) Celsius
DID Discharge Ionization Detector
DIN Deutsche Industrie Normen (German Industrial Standards)
DISS Diameter Index Safety System
DOT Department of Transportation
ea each
ECD Electron Capture Detector
EPA Environmental Protection
FID Flame Ionization Detector
FNPT Female National Pipe Thread
F.O.B. Freight on Board
FPD Flame Photometric Detector
FPT Female Pipe Thread
ft foot, feet
ft3, cu ft cubic foot (feet)
FTIR Fourier Transform Infrared Spectrometer or Spectroscopy
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
°F degree(s) Fahrenheit
g gram(s)
gal gallon(s)
GC Gas Chromatography or Chromatograph
GMIS Gas Manufacturers Intermediate Standard
GMP Good Manufacturing Practice(s)
GPA Gas Processors Association
Hall Electrolytic Conductivity Detector
HAP Hazardous Air Pollutants
HID Helium Ionization Detector
hr hour
Hz hertz
ICP Inductively Coupled Plasma (Spectroscopy)
ID identification or inside diameter
IDLH Immediately Dangerous to Life or Health
in inch
in3, cu in cubic inch(es)
ISO International Organization for Standardization
J joule
K Kelvin
kg kilogram(s)
kPa Kilopascal(s)
°K degree(s) Kelvin
L liter(s)
lb pound(s)
LC Liquid Chromatography
LEL Lower Explosive Limit
Lpm liters per minute
μ micron(s), 10–6 m
m3 cubic meter(s)
mA milliampere
max maximum
mg milligram(s)
min minute(s)
ml milliliter(s)
mm millimeter(s)
MNPT Male National Pipe Thread
mol.wt. molecular weight
MOS Metal Oxide Semiconductor
MPT Male Pipe Thread
mp melting point
MS Mass Spectrometry
MSDS Material Safety Data Sheet
MTBE Methyl Tertiary Butyl Ether
MVFS Male Vacuum Face Seal
MW molecular weight
Symbol Definition
N/A Not Applicable
nbp normal boiling point
NDIR Non–Dispersive Infrared Analyzer
NDUV Non–Dispersive Ultraviolet Analyzer
NER normal evaporation rate
NFNF National Formulary
NFPA National Fire Protection Association
NIOSH National Institute for Occupational Safety and Health
NIST National Institute of Standards and Technology
nm nanometer(s)
NMR Nuclear Magnetic Resonance Spectroscopy
No number
nom nominal
NOS Not Otherwise Specified
NPD Nitrogen/Phosphorous Detector
NPT National Pipe Thread
NTP Normal Temperature and Pressure
NTRM NIST Traceable Reference Material
OD Outside Diameter
Ohm–cm ohms centimeter
OSHA Occupational Safety and Health Administration
oz ounce(s
Pa Pascal(s)
PAMS Photochemical Air Monitoring Systems
PID Photo Ionization Detector
ppb part(s) per billion
ppba part(s) per billion atomic
ppbv part(s) per billion by volume
ppbw part(s) per billion by weight
ppm part(s) per million
ppma part(s) per million atomic
ppmv part(s) per million by volume
ppmw part(s) per million by weight
ppt part(s) per trillion
ppta part(s) per trillion atomic
pptv part(s) per trillion by volume
pptw part(s) per trillion by weight
psi pound(s) – force per square inch
psia pound(s) – force per square inch absolute
psig pound(s) – force per square inch gauge
QA Quality Assurance
QC Quality Control
Ra Roughness average
RFO Restricted Flow Orifice
°R degree(s) Rankine
scc standard cubic centimeters
sccm standard cubic centimeters per minute
sccs standard cubic centimeters per second
scfh standard cubic feet per hour
scfm standard cubic feet per minute
scfs standard cubic feet per second
sec second(s)
SFC Supercritical Fluid Chromatography
SFE Supercritical Fluid Extraction
slpm standard liters per minute
sp. gr. specific gravity
sp. vol. specific volume
SRM Standard Reference Materials
SS Stainless Steel
Stn. Stl Stainless Steel
STEL Short Term Exposure Limit
STP Standard Temperature and Pressure
TCD Thermal Conductivity Detector
TEA Transversely Excited Atmosphere
THC Total Hydrocarbon Content
TLV Threshold Limit Value
tp triple point
TPH Total Petroleum Hydrocarbons
TWA Time Weighted Average
UEL Upper Explosive Limiit
UHP Ultra High Purity
UN United Nations
USP United States Pharmacopoeia
VAC Volts Alternating Current
VDC Volts Direct Current
VOC Volatile Organic Compounds
vol volume
vol% volume percent
w.c. water column pressure
wt. weight
wt% weight percent
wt. ppm weight parts per million
yd yard(s)
Other Symbols
> Greater than
Greater than or equal
< Less than
Less than or equal


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