40 CFR 63.3 - Units and abbreviations.

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§ 63.3 Units and abbreviations.
Used in this part are abbreviations and symbols of units of measure. These are defined as follows:
(a) System International (SI) units of measure:
A = ampere
g = gram
Hz = hertz
J = joule
°K = degree Kelvin
kg = kilogram
l = liter
m = meter
m3 = cubic meter
mg = milligram = 10−3 gram
ml = milliliter = 10−3 liter
mm = millimeter = 10−3 meter
Mg = megagram = 106 gram = metric ton
MJ = megajoule
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
µl = microliter = 10−6 liter
(b) Other units of measure:
Btu = British thermal unit
°C = degree Celsius (centigrade)
cal = calorie
cfm = cubic feet per minute
cc = cubic centimeter
cu ft = cubic feet
d = day
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
ft2 = square feet
ft3 = cubic feet
gal = gallon
gr = grain
g-eq = gram equivalent
g-mole = gram mole
hr = hour
in. = inch
in. H2 O = inches of water
K = 1,000
kcal = kilocalorie
lb = pound
lpm = liter per minute
meq = milliequivalent
min = minute
MW = molecular weight
oz = ounces
ppb = parts per billion
ppbw = parts per billion by weight
ppbv = parts per billion by volume
ppm = parts per million
ppmw = parts per million by weight
ppmv = parts per million by volume
psia = pounds per square inch absolute
psig = pounds per square inch gage
°R = degree Rankine
scf = cubic feet at standard conditions
scfh = cubic feet at standard conditions per hour
scm = cubic meter at standard conditions
scmm = cubic meter at standard conditions per minute
sec = second
sq ft = square feet
std = at standard conditions
v/v = volume per volume
yd2 = square yards
yr = year
(c) Miscellaneous:
act = actual
avg = average
I.D. = inside diameter
M = molar
N = normal
O.D. = outside diameter
% = percent
[59 FR 12430, Mar. 16, 1994, as amended at 67 FR 16598, Apr. 5, 2002]

Title 40 published on 2014-07-01

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  • 2014-11-25; vol. 79 # 227 - Tuesday, November 25, 2014
    1. 79 FR 70102 - National Emission Standards for Hazardous Air Pollutants; Delegation of Authority to Texas
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      ENVIRONMENTAL PROTECTION AGENCY
      Direct final rule; delegation of authority.
      This rule is effective on January 26, 2015 without further notice, unless EPA receives relevant adverse comment by December 26, 2014. If EPA receives such comment, EPA will publish a timely withdrawal in the Federal Register informing the public that this rule will not take effect.
      40 CFR Part 63

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United States Code

Title 40 published on 2014-07-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR 63 after this date.

  • 2014-12-12; vol. 79 # 239 - Friday, December 12, 2014
    1. 79 FR 73872 - Phosphoric Acid Manufacturing and Phosphate Fertilizer Production RTR and Standards of Performance for Phosphate Processing; Extension of Comment Period
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      ENVIRONMENTAL PROTECTION AGENCY
      Notice of proposed rulemaking; extension of public comment period.
      Comments. The public comment period for the proposed rule published in the Federal Register on November 7, 2014, (79 FR 66512) is being extended for 30 days to January 21, 2015.
      40 CFR Parts 60 and 63