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The abbreviations used in this subpart have the following meanings in both capital and lowercase:
ASTM - American Society for Testing and Materials.
C - Celsius.
cc - Cubic centimetre(s).
cfh - Cubic feet per hour.
cfm - Cubic feet per minute.
CH4 methane.
cm - Centimetre(s).
CO - Carbon monoxide.
CO2 - Carbon dioxide.
Conc - Concentration.
cu. - Cubic.
CVS - Constant volume sampler.
EGR - Exhaust gas recirculation.
EP - End point.
EPA - Environmental Protection Agency.
F - Fahrenheit.
h - hour.
HC - Hydrocarbon(s).
Hg - Mercury.
H2O - Water.
in. - Inch(es).
K - Kelvin.
kg - Kilogram(s).
km - Kilometre(s).
kpa - Kilopascals.
lb - Pound(s).
m - Metre(s).
mph - Miles per hour.
mm - Millimetre(s).
N2 - Nitrogen.
N2O nitrous oxide.
NOX - Oxides of nitrogen.
No. - Number.
O2 - Oxygen.
Pa - Pascal(s).
Pb - lead.
ppm - Parts per million by volume.
psi - Pounds per square inch.
psig - Pounds per square inch gauge.
R - Rankine.
rpm - Revolutions per minute.
wt - Weight.
° - Degree(s).
% - Percent.
[42 FR 1126, Jan. 5, 1977, as amended at 74 FR 56373, Oct. 30, 2009]