TITLE 40 - PROTECTION OF ENVIRONMENT

CHAPTER I - ENVIRONMENTAL PROTECTION AGENCY

SUBCHAPTER C - AIR PROGRAMS

PART 63 - NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES

subpart a - GENERAL PROVISIONS

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 m 3 = cubic meter mg = milligram = 103 gram ml = milliliter = 103 liter mm = millimeter = 103 meter Mg = megagram = 10 6 gram = metric ton MJ = megajoule mol = mole N = newton ng = nanogram = 109 gram nm = nanometer = 109 meter Pa = pascal s = second V = volt W = watt = ohm g = microgram = 106 gram l = microliter = 106 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 ft 2 = square feet ft 3 = 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 yd 2 = 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]