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—jouleK—degree Kelvinkg—kilogramm—meterm3—cubic metermg—milligram—10 ?3 grammm—millimeter—10 ?3 meterMg—megagram—106 grammol—moleN—newtonng—nanogram—10 ?9 gramnm—nanometer—10 ?9 meterPa—pascals—secondV—voltW—watt ?—ohm µg—microgram—10 ?6 gram

(b) Other units of measure:

Btu—British thermal unit °C—degree Celsius (centigrade) cal—calorie cfm—cubic feet per minutecu ft—cubic feetdcf—dry cubic feetdcm—dry cubic meterdscf—dry cubic feet at standard conditionsdscm—dry cubic meter at standard conditionseq—equivalent°F—degree Fahrenheitft—feetgal—gallongr—graing-eq—gram equivalenthr—hourin—inchk—1,000l—literlpm—liter per minutelb—poundmeq—milliequivalentmin—minuteml—millilitermol. wt.—molecular weightppb—parts per billionppm—parts per millionpsia—pounds per square inch absolutepsig—pounds per square inch gage°R—degree Rankinescf—cubic feet at standard conditionsscfh—cubic feet per hour at standard conditionsscm—cubic meter at standard conditionssec—secondsq ft—square feetstd—at standard conditions

(c) Chemical nomenclature:

CdS—cadmium sulfideCO—carbon monoxideCO2—carbon dioxideHCl—hydrochloric acidHg—mercuryH2O—waterH2S—hydrogen sulfideH2SO4—sulfuric acidN2—nitrogenNO—nitric oxideNO2—nitrogen dioxideNOX—nitrogen oxidesO2—oxygenSO2—sulfur dioxideSO3—sulfur trioxideSOX—sulfur oxides

(d) Miscellaneous:

A.S.T.M.—American Society for Testing and Materials[42 FR 37000, July 19, 1977; 42 FR 38178, July 27, 1977]