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 = ampereg = gramHz = hertzJ = joule°K = degree Kelvinkg = kilograml = literm = meterm3 = cubic metermg = milligram = 10?3 gramml = milliliter = 10?3 litermm = millimeter = 10?3 meterMg = megagram = 106 gram = metric tonMJ = megajoulemol = moleN = newtonng = nanogram = 10?9 gramnm = nanometer = 10?9 meterPa = pascals = secondV = voltW = watt? = ohmµg = microgram = 10?6 gramµl = microliter = 10?6 liter

(b) Other units of measure:

Btu = British thermal unit °C = degree Celsius (centigrade)cal = caloriecfm = cubic feet per minutecc = cubic centimetercu ft = cubic feetd = daydcf = dry cubic feetdcm = dry cubic meterdscf = dry cubic feet at standard conditionsdscm = dry cubic meter at standard conditionseq = equivalent °F degree Fahrenheitft = feetft2 = square feetft3 = cubic feetgal = gallongr = graing-eq = gram equivalentg-mole = gram molehr = hourin. = inchin. H2 O = inches of waterK = 1,000kcal = kilocalorielb = poundlpm = liter per minutemeq = milliequivalentmin = minuteMW = molecular weightoz = ouncesppb = parts per billionppbw = parts per billion by weightppbv = parts per billion by volumeppm = parts per millionppmw = parts per million by weightppmv = parts per million by volumepsia = pounds per square inch absolutepsig = pounds per square inch gage°R = degree Rankinescf = cubic feet at standard conditionsscfh = cubic feet at standard conditions per hourscm = cubic meter at standard conditionsscmm = cubic meter at standard conditions per minute sec = secondsq ft = square feetstd = at standard conditionsv/v = volume per volumeyd2 = square yardsyr = year

(c) Miscellaneous:

act = actualavg = averageI.D. = inside diameterM = molarN = normalO.D. = outside diameter% = percent[59 FR 12430, Mar. 16, 1994, as amended at 67 FR 16598, Apr. 5, 2002]