Appendix. A.3 Chemical Resistance of Materials 1799 Chemical Resistance of Materials (Table A.3a) 1800

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1 Appendix A.1 International System of Units 1767 International System of Units (Table A.1a) 1768 Alphabetical List of Units (Symbols of SI units given in parentheses) (Table A.1b) 1769 A.2 Engineering Conversion Factors 1777 Conversion Factors (Table A.2a) 1777 Units of Area (Table A.2b) 1788 Units of Density (Table A.2c) 1788 Units of Work, Energy, Heat (Table A.2d) 1788 Units of Mass Flow (Table A.2e) 1788 Units of Volume Flow (Table A.2f) 1788 Units of Length (Table A.2g) 1788 Linear Conversion (Table A.2h) 1789 Units of Power (Table A.2i) 1790 Units of Pressure (Table A.2j) 1790 Pressure Conversion (Table A.2k) 1791 Pressure Head Conversion (Table A.2l) 1792 Temperature Conversion (Table A.2m) 1793 Units of Time (Table A.2n) 1793 Units of Velocity (Table A.2o) 1793 Viscosity Conversion (Table A.2p) 1794 Viscosity Conversion Chart (Table A.2q) 1796 Approximate Viscosity Conversion Chart (Table A.2r) 1797 Units of Volume (Table A.2s) 1798 Units of Weight (Table A.2t) 1798 Weight Conversion (Table A.2u) 1798 A.3 Chemical Resistance of Materials 1799 Chemical Resistance of Materials (Table A.3a) 1800 A.4 Composition of Metallic and Other Materials 1806 Composition of Metallic and Other Materials (Table A.4a) 1806 A.5 Steam and Water Tables 1809 Dry Saturated Steam: Temperature Table (Table A.5a) 1810 Properties of Superheated Steam (Table A.5b) 1812 Properties of Water at Various Temperatures from 40 to 540 F (4.4 to C) (Table A.5c) 1816 A.6 Friction Loss in Pipes 1817 Friction Loss Modulus for 100 ft of 1 in. Steel Pipe (Figure A.6a) 1818 Friction Loss Modulus for 100 ft of 1.5 in. Steel Pipe (Figure A.6b) 1818 Friction Loss Modulus for 100 ft of 2 in. Steel Pipe (Figure A.6c) 1819 Friction Loss Modulus for 100 ft of 3 in. Steel Pipe (Figure A.6d) 1819 Friction Loss Modulus for 100 ft of 4 in. Steel Pipe (Figure A.6e)

2 1766 Analytical Instrumentation Friction Loss Modulus for 100 ft of 6 in. Steel Pipe (Figure A.6f) 1820 A.7 Tank Volumes 1821 Capacity of Round Tanks (per foot of depth) (Table A.7a) 1821 Capacity of Partially Filled Horizontal Tanks (Table A.7b) 1822 Capacities of Various Cylinders in U.S. Gallons (Table A.7c) 1823 A.8 Directory of Lost Companies 1824 Introduction 1824 Alphabetic Listing of Lost Companies (Table A.8a) 1825

3 A.1 International System of Units The decimal system of units was conceived in the 16th century when there was a great confusion and jumble of units of weights and measures. It was not until 1790, however, that the French National Assembly requested the French Academy of Sciences to work out a system of units suitable for adoption by the entire world. This system, based on the meter (metre) as a unit of length and the gram as a unit of mass, was adopted as a practical measure to benefit industry and commerce. Physicists soon realized its advantages and it was adopted also in scientific and technical circles. The importance of the regulation of weights and measures was recognized in Article 1, Section 8, when the U.S. Constitution was written in 1787, but the metric system was not legalized in this country until In 1893, the international meter and kilogram became the fundamental standards of length and mass in the United States, both for metric and customary weights and measures. The tables of conversion factors presented here are intended to serve two purposes: 1. To express the definitions of miscellaneous units of measure as exact numeral multiples of coherent metric units. Relationships that are exact in terms of the base unit are followed by an asterisk. Relationships that are not followed by an asterisk are either the results of physical measurements or are only approximate. 2. To provide multiplying factors for converting expressions of measurements given by numbers and miscellaneous units to corresponding new numbers and metric units. Conversion factors are presented for ready adaptation to computer readout and electronic data transmission. The factors are written as a number equal to or greater than 1 and less than 10 with six or fewer decimal places. This number is followed by the letter E (for exponent), a plus or minus symbol, and two digits that indicate the power of 10 by which the number must be multiplied to obtain the correct value. For example: E-02 is or Similarly, or E+03 is An asterisk (*) after the sixth decimal place indicates that the conversion factor is exact and that all subsequent digits are zero. When a figure is to be rounded to fewer digits than the total number available, the procedure should be as follows: 1. When the first digit discarded is less than 5, the last digit retained should not be changed. For example, , if rounded to four digits, would be 3.463; if rounded to three digits, When the first digit discarded is greater than or if it is a 5, followed by at least one digit other than 0, the last figure retained should be increased by one unit. For example , if rounded to four digits, would be 8.377; if rounded to three digits, When the first digit discarded is exactly 5, followed only by zeros, the last digit retained should be rounded upward if it is an odd number, but no adjustment made if it is an even number. For example, 4.365, when rounded to three digits, becomes The number would also round to the same value, 4.36, if rounded to three digits. Where fewer than six decimal places is shown, more precision is not warranted. 1767

4 1768 A.1 International System of Units TABLE A.1a International System of Units Quantity Unit SI Symbol Formula Quantity Unit SI Symbol Formula Base Units length meter m mass kilogram kg time second s electric current ampere A thermodynamic temperature kelvin K amount of substance mole mol luminous intensity candela cd Supplementary Units plane angle radian rad solid angle steradian sr acceleration activity (of a radioactive source) angular acceleration Derived Units meter per second squared disintegration per second radian per second squared m/s 2 (disintegration)/s rad/s 2 angular velocity radian per second rad/s area square meter m 2 density kilogram per cubic meter kg/m 3 electric capacitance farad F As/V electrical siemens S A/V conductance electric field strength volt per meter V/m electric inductance henry H Vs/A electric potential difference volt V W/A electric resistance ohm W V/A electromotive force energy entropy force frequency illuminance luminance luminous flux magnetic field strength magnetic flux magnetic flux density magnetomotive force power pressure quantity of electricity quantity of heat radiant intensity specific heat stress thermal conductivity velocity viscosity, dynamic viscosity, kinematic voltage volume wavenumber work volt joule joule per kelvin newton hertz lux candela per square meter lumen ampere per meter weber telsa ampere watt pascal coulomb joule watt per steradian joule per kilogram-kelvin pascal watt per meterkelvin meter per second pascal-second square meter per second volt cubic meter reciprocal meter joule V J N Hz lx lm Wb T A W Pa C J Pa V J W/A Nm J/K kgm/s 2 (cycle)/s lm/m 2 cd/m 2 cdsr A/m Vs Wb/m 2 J/s N/m 2 As Nm W/sr J/kgK N/m 2 W/mK m/s Pas m 2 /s W/A m 3 (wave)/m Nm

5 TABLE A.1b Alphabetical List of Units (Symbols of SI units given in parentheses) To convert from To Multiply by To convert from To Multiply by A abampere ampere (A) *E+01 bar *E+05 abcoulomb coulomb (C) *E+01 barn meter 2 (m 2 ) *E-28 abfarad farad (F) *E+09 barrel (for petroleum, 42 gal) E-01 abhenry henry (H) *E+09 board foot E-03 abmho siemens (S) *E+09 British thermal unit (International Table) b E+03 abohm ohm (W) *E+09 British thermal unit (mean) E+03 abvolt volt (V) *E+08 British thermal unit (thermochemical) E+03 acre foot (U.S. survey) a E+03 British thermal unit (39 F) E+03 acre (U.S. survey) a meter 2 (m 2 ) E+03 British thermal unit (59 F) E+03 ampere hour coulomb (C) *E+03 British thermal unit (60 F) E+03 are angstrom astronomical unit meter 2 (m 2 ) *E *E E+11 Btu (International Table) ft/h ft 2 F (k, thermal conductivity) Btu (thermochemical) ft/h ft 2 F watt per meter-kelvin (W/mK) watt per meter-kelvin (W/mK) E E+00 (k, thermal conductivity) atmosphere (standard) *E+05 atmosphere (technical = 1 kgf/cm 2 Btu (International Table) in./h ft 2 F ) *E+04 (k, thermal conductivity) watt per meter-kelvin (W/mK) E-01 a Since 1893, the U.S. basis of length measurement has been derived from metric standards. In 1959, a small refinement was made in the definition of the yard to resolve discrepancies Btu (thermochemical) in./h ft 2 F (k, thermal conductivity) watt per meter-kelvin (W/mK) E-01 both in this country and abroad, which changed its length from 3600/3937 m to m Btu (International Table) in./s ft 2 F watt per meter-kelvin (W/mK) E+02 exactly. This resulted in the new value being shorter by two parts in a million. (k, thermal conductivity) At the same time it was decided that any data in feet derived from and published as a result Btu (thermochemical) in./s ft 2 F watt per meter-kelvin E+02 of geodetic surveys within the United States would remain with the old standard (1 ft = 1200/3937 m) until further decision. This foot is named the U.S. survey foot. (k, thermal conductivity) (W/mK) As a result all U.S. land measurements in U.S. customary units will relate to the meter by Btu (International Table)/h E-01 the old standard. All the conversion factors in these tables for units referenced to this footnote Btu (International Table)/s E+03 are based on the U.S. survey foot, rather than the international foot. Conversion factors for the land measures given below may be determined from the following Btu (thermochemical)/h E+01 relationships: Btu (thermochemical)/min E+01 1 league = 3 miles (exactly) Btu (thermochemical)/s E+03 1 rod = 16 / 2 feet (exactly) 1 section = 1 square mile (exactly) Btu (International Table)/ft 2 joule per meter 2 (J/m 2 ) E+04 1 township = 36 square miles (exactly) 1 chain = 66 feet (exactly) b This value was adopted in Some of the older International Tables use the value E+03. The exact conversion factor is *E+03. B A.1 International System of Units 1769

6 TABLE A.1b Continued Alphabetical List of Units (Symbols of SI units given in parentheses) To convert from To Multiply by To convert from To Multiply by Btu (thermochemical)/ft 2 Btu (thermochemical)/ft 2 Btu (thermochemical)/ft 2 Btu (thermochemical)/ft 2 Btu (thermochemical)/in. 2 h s min Btu (International Table)/h ft 2 (C, thermal conductance) Btu (thermochemical)/h ft 2 (C, thermal conductance) Btu (International Table)/s ft 2 Btu (thermochemical)/ s ft 2 s F Btu (International Table)/lb Btu (thermochemical)/lb Btu (International Table)/lb F (c, heat capacity) Btu (thermochemical)/lb F (c, heat capacity) bushel (U.S.) F F F caliber (inch) calorie (International Table) calorie (mean) calorie (thermochemical) calorie (15 C) calorie (20 C) calorie (kilogram, International Table) calorie (kilogram, mean) joule per meter 2 (J/m 2 ) watt per meter 2 (W/m 2 ) watt per meter 2 (W/m 2 ) watt per meter 2 (W/m 2 ) watt per meter 2 (W/m) 2 watt per meter 2 -kelvin (W/m 2 K) watt per meter 2 -kelvin (W/m 2 K) watt per meter 2 -kelvin (W/m 2 K) watt per meter 2 -kelvin (W/m 2 K) joule per kilogram (J/kg) joule per kilogram (J/kg) joule per kilogram-kelvin (J/kg K) joule per kilogram-kelvin (J/kg K) C E E E E E E E E E *E E *E E E *E *E E *E E E *E E+03 calorie (kilogram, thermochemical) cal (thermochemical)/cm 2 cal (International Table)/g cal (thermochemical)/g cal (International Table)/g C cal (thermochemical)/g C cal (thermochemical)/min cal (thermochemical)/s cal (thermochemical)/cm 2 min cal (thermochemical)/cm 2 s cal (thermochemical)/cm s C carat (metric) centimeter of mercury (0 C) centimeter of water (4 C) centipoise centistokes circular mil clo cup curie joule per meter 2 (J/m 2 ) joule per kilogram (J/kg) joule per kilogram (J/kg) joule per kilogram-kelvin (J/kg K) joule per kilogram-kelvin (J/kg K) watt per meter 2 (W/m 2 ) watt per meter 2 (W/m 2 ) watt per meter-kelvin (W/m K) pascal second (Pa s) meter 2 per second (m 2 /s) meter 2 (m 2 ) kelvin meter 2 per watt (K m 2 /W) becquerel (Bq) *E *E *E *E *E *E E *E E *E *E *E E E *E *E E E E *E+10 D day (mean solar) second (s) E+04 day (sidereal) degree (angle) degree Celsius second (s) radian (rad) Kelvin (K) E E A.1 International System of Units

7 degree centigrade [see footnote c] t K = t ºC erg/(cm 2 s) watt per meter 2 (W/m 2 ) *E-03 degree Fahrenheit degree Celsius t ºC = (t ºF -32)/1.8 erg/s *E-07 degree Fahrenheit kelvin (K) t K = (t ºF )/1.8 erg *E-07 degree Rankine kelvin (K) t K = t ºR /1.8 F h ft 2 /Btu (International Table) kelvin meter 2 per watt E-01 (R, thermal resistance) (Km 2 /W) F hft 2 /Btu (thermochemical kelvin meter 2 per watt E-01 (R, thermal resistance) (Km 2 /W) denier kilogram per meter (kg/m) E-07 dyne newton (N) *E-05 dyne/cm newton meter (N m) *E-07 dyne/cm *E-01 E electronvolt E-19 EMU of capacitance farad (F) *E+09 EMU of current ampere (A) *E+01 EMU of electric potential volt (V) *E-08 EMU of inductance henry (H) *E-09 EMU of resistance ohm (W) *E-09 ESU of capacitance farad (F) E-12 ESU of current ampere (A) E-10 ESU of electric potential volt (V) E+02 ESU of inductance henry (H) E+11 ESU of resistance ohm (W) E+11 c The SI unit of thermodynamic temperature is the kelvin (K), and this unit is properly used for expressing thermodynamic temperature and temperature intervals. Wide use is also made of the degree Celsius ( C), which is the SI unit for expressing Celsius temperature and temperature intervals. The Celsius scale (formerly called centigrade) is related directly to thermodynamic temperature (kelvins) as follows: 1. The temperature interval one degree Celsius equals one kelvin exactly. 2. Celsius temperature (t) is related to thermodynamic temperature (T) by the equation t = T - T 0, where T 0 = K by definition. faraday (based on carbon-12) faraday (chemical) faraday (physical) fathom fermi (femtometer) fluid ounce (U.S.) foot foot (U.S. survey) a foot of water (39.2 F) ft 2 ft 2 /h (thermal diffusivity) ft 2 /s ft 3 (volume; section modulus) ft 3 /min ft 3 /s ft 4 (moment of section) d ft/h ft/min ft/s ft/s 2 footcandle footlambert F coulomb (C) coulomb (C) coulomb (C) meter 2 (m 2 ) meter 2 per second (m 2 /s) meter 2 per second (m 2 /s) meter 3 per second (m 3 /s) meter 3 per second (m 3 /s) meter 4 (m 4 ) meter per second (m/s) meter per second (m/s) meter per second (m/s) meter per second 2 (m/s 2 ) lux (lx) candela per meter 2 (cd/m 2 ) d This is sometimes called the moment of inertia of a plane section about a specified axis E E E E *E E *E E E *E *E *E E E E E E *E *E *E E E+00 A.1 International System of Units 1771

8 TABLE A.1b Continued Alphabetical List of Units (Symbols of SI units given in parentheses) To convert from To Multiply by To convert from To Multiply by ftlbf ftlbf/h E E-04 H ftlbf/min ftlbf/s E E+00 hectare horsepower (550 ftlbf/s) meter 2 (m 2 ) *E E+02 ftpoundal E-02 horsepower (boiler) E+03 free fall, standard (g) meter per second 2 (m/s 2 ) *E+00 horsepower (electric) *E+02 horsepower (metric) E+02 G horsepower (water) E+02 gal meter per second 2 (m/s 2 ) *E-02 horsepower (U.K.) E+02 gallon (Canadian liquid) gallon (U.K. liquid) gallon (U.S. dry) gallon (U.S. liquid) gallon (U.S. liquid) per day gallon (U.S. liquid) per minute meter 3 per second (m 3 /s) meter 3 per second (m 3 /s) E E E E E E-05 hour (mean solar) hour (sidereal) hundredweight (long) hundredweight (short) second (s) second (s) I E E E E+01 gallon (U.S. liquid) per hph meter 3 per joule (m 3 /J) E-09 inch *E-02 (SFC, specific fuel consumption) inch of mercury (32 F) E+03 gamma tesla (T) *E-09 inch of mercury (60 F) E+03 gauss tesla (T) *E-04 inch of water (39.2 F) E+03 gilbert ampere (A) E-01 inch of water (60 F) E+02 gill (U.K.) E-04 in. 2 meter 2 (m 2 ) *E-04 gill (U.S.) E-04 in. 3 (volume; section modulus) e E-05 grad degree (angular) *E-01 in. 3 /min meter 3 per second (m 3 /s) E-07 grad radian (rad) E-02 in. 4 (moment of section) 4 meter 4 (m 4 ) E-07 grain (1/7000 lb avoirdupois) *E-05 in./s meter per second (m/s) *E-02 grain (lb avoirdupois/7000)/gal E-02 in./s 2 meter per second 2 (m/s 2 ) *E-02 (U.S. liquid) gram *E-03 K g/cm *E+03 kayser 1 per meter (1/m) *E+02 kelvin degree Celsius t C = t K gram-force/cm *E+01 kilocalorie (International Table) *E A.1 International System of Units e The exact conversion factor is *E-05.

9 kilocalorie (mean) E+03 mile (international) *E+03 kilocalorie (thermochemical) *E+03 mile (statute) E+03 kilocalorie (thermochemical)/min E+01 mile (U.S. survey) a E+03 kilocalorie (thermochemical)/s *E+03 mile (international nautical) *E+03 kilogram-force (kgf) newton (N) *E+00 mile (U.K. nautical) *E+03 kgf m newton meter (N m) *E+00 mile (U.S. nautical) *E+03 kgf s 2 /m (mass) *E+00 mi 2 (international) meter 2 (m 2 ) E+06 kgf/cm *E+04 mi 2 (U.S. survey) a meter 2 (m 2 ) E+06 kgf/m *E+00 mi/h (international) meter per second (m/s) *E-01 kgf/mm *E+06 mi/h (international) kilometer per hour (km/h) *E+01 km/h meter per second (m/s) E-01 mi/min (international) meter per second (m/s) *E+01 kilopond newton (N) *E+00 mi/s (international) meter per second (m/s) *E+03 kw h *E+06 millibar *E+02 kip (1000 lbf) newton (N) E+03 millimeter of mercury (0 C) E+02 kip/in 2 (ksi) E+06 minute (angle) radian (rad) E-04 knot (international) meter per second (m/s) E-01 minute (mean solar) second (s) E+01 L minute (sidereal) second (s) E+01 lambert candela per meter 2 (cd/m 2 ) 1/p *E+04 month (mean calendar) second (s) E+06 lambert candela per meter 2 (cd/m 2 ) E+03 langley joule per meter 2 (J/m 2 ) *E+04 oersted ampere per meter (A/m) E+01 league [see footnote a] ohm centimeter ohm meter (W m) *E-02 light year E+15 ohm circular-mill per foot ohm millimeter 2 per meter liter f *E-03 (Wmm 2 /m) O E-03 M ounce (avoirdupois) E-02 maxwell weber (Wb) *E-08 ounce (troy or apothecary) E-02 mho siemens (S) *E+00 ounce (U.K. fluid) E-05 microinch *E-08 ounce (U.S. fluid) E-05 micron *E-06 ounce-force newton (N) E-01 mil *E-05 ozfin. newton meter (N m) E-03 f In 1964 the General Conference on Weights and Measures adopted the name liter as a special name for decimeter. Prior to this decision the liter differed slightly (previous value, dm 3 ) and in expression of precision volume measurement this fact must be kept in mind. A.1 International System of Units 1773

10 TABLE A.1b Continued Alphabetical List of Units (Symbols of SI units given in parentheses) To convert from To Multiply by To convert from To Multiply by oz (avoirdupois)/gal (U.K. liquid) oz (avoirdupois)/gal (U.S. liquid) E E+00 pint (U.S. dry) pint (U.S. liquid) point (printer s) E E *E-04 oz (avoirdupois)/in 3 poise (absolute viscosity) pascal second (Pas) *E E+03 pound (lb avoirdupois) g E-01 pound (troy or apothecary) E-01 oz (avoirdupois)/ft E-01 lbft 2 (moment of inertia) kilogram meter 2 (kgm 2 ) E-02 oz (avoirdupois)/yd 2 kilogram per meter 2 (kg/m 2 ) E-02 lbin. 2 (moment of inertia) lb/fth kilogram meter 2 (kgm 2 ) pascal second (Pas) E E-04 lb/fts pascal second (Pas) E+00 P lb/ft 2 kilogram per meter 2 (kg/m 2 ) E+00 parsec E+16 lb/ft E+01 peck (U.S.) E-03 lb/gal (U.K. liquid) E+01 pennyweight E-03 lb/gal (U.S. liquid) E+02 perm (0 C) kilogram per pascal E-11 lb/h kilogram per second (kg/s) E-04 second meter 2 perm (23 C) (kg/pasm 2 ) kilogram per pascal second meter 2 (kg/pasm 2 ) E-11 lb/hph (SFC, specific fuel consumption) lb/in. 3 lb/min lb/s kilogram per joule (kg/j) kilogram per second (kg/s) kilogram per second (kg/s) E E E E-01 (kg/pasm) kilogram per pascal E-12 second meter lb/yd 3 poundal newton (N) E E-01 permin. (0 C) kilogram per pascal E-12 poundal/ft E+00 permin. (23 C) second meter (kg/pasm) kilogram per pascal second meter (kg/pasm) E-12 poundals/ft 2 pound-force (in.f) h lbfft pascal second (Pas) newton (N) newton meter (N m) E E E A.1 International System of Units phot lumen per meter 2 (lm/m 2 ) *E+04 g The exact conversion factor is *E-01 pica (printer s) E-03

11 lbf ft/in. newton meter per meter (N m/m) E+01 statampere lbf in. newton meter (N m) E-01 lbfin./in. newton meter per meter E+01 (Nm/m) lbfs/ft 2 pascal second (Pas) E+01 lbfs/in. 2 pascal second (Pas) E+03 lbf/ft newton per meter (N/m) E+01 lbf/ft E+01 lbf/in. newton per meter (N/m) E+02 lbf/in. 2 (psi) E+03 lbf/lb (thrust/weight [mass] ratio) newton per kilogram (N/kg) E+00 statcoulomb statfarad stathenry statmho statohm statvolt stere stilb stokes (kinematic viscosity) ampere (A) coulomb (C) farad (F) henry (H) siemens (S) ohm (W) volt (V) candela per meter 2 (cd/m 2 ) meter 2 per second (m 2 /s) E E E E E E E *E *E *E-04 Q T quart (U.S. dry) E-03 tablespoon E-05 quart (U.S. liquid) E-04 teaspoon E-06 R rad (radiation dose absorbed) gray (Gy) *E-02 rhe 1 per pascal second *E+01 (1/Pa s) rod [see footnote a] roentgen coulomb per kilogram (C/kg) 2.58 E-04 S second (angle) radian (rad) E-06 second (sidereal) second (s) E-01 section meter 2 (m 2 ) [see footnote a] shake second (s) *E-08 slug slug/fts slug/ft 3 pascal second (Pas) E E E+02 h The exact conversion factor is *E+00. tex therm ton (assay) ton (long, 2240 lb) ton (metric) ton (nuclear equivalent of TNT) ton (refrigeration) ton (register) ton (short, 2000 lb) ton (long)/yd 3 ton (short)/yd 3 ton (short)/h i Defined (not measured) value. kilogram per meter (kg/m) kilogram per second (kg/s) *E E E E *E E+09 i E E E E E E-01 A.1 International System of Units 1775

12 TABLE A.1b Continued Alphabetical List of Units (Symbols of SI units given in parentheses) To convert from To Multiply by To convert from To Multiply by ton-force (2000 lbf) tonne newton (N) E *E+03 W/cm 2 W/in. 2 watt per meter (W/m 2 ) watt per meter 2 (W/m 2 ) *E E+03 torr (mmhg, 0 C) E+02 township meter 2 (m 2 ) [see footnote a] Y U yard yd 2 meter 2 (m 2 ) *E E-01 unit pole weber (Wb) E-07 yd E-01 W yd 3 /min meter 3 per second (m 3 /s) E-02 Wh *E+03 year (365 days) second (s) E+07 year (sidereal) second (s) E+07 year (tropical) second (s) E+07 Ws *E A.1 International System of Units