1、39.1CHAPTER 39UNITS AND CONVERSIONSTable 1 Conversions to I-P and SI Units(Multiply I-P values by conversion factors to obtain SI; divide SI values by conversion factors to obtain I-P)Multiply I-P By To Obtain SI Multiply I-P By To Obtain SIacre (43,560 ft2) 0.4047 ha inlbf(torque or moment). 113 mN
2、m4046.873 m2in2645.16 mm2atmosphere (standard) *101.325 kPa in3(volume) 16.3874 mLbar. *100 kPa in3/min (SCIM). 0.273117 mL/sbarrel (42 U.S. gal, petroleum). 159.0 L in3(section modulus) 16,387 mm30.1580987 m3in4(section moment) 416,231 mm4Btu (International Table) 1055.056 J kWh *3.60 MJBtu (thermo
3、chemical) 1054.350 J kW/1000 cfm 2.118880 kJ/m3Btu/ft2(International Table). 11,356.53 J/m2kilopond (kg force) . 9.81 NBtu/ft3(International Table). 37,258.951 J/m3kip (1000 lbf) 4.45 kNBtu/gal 278,717.1765 J/m3kip/in2(ksi). 6.895 MPaBtuft/hft2 F 1.730735 W/(mK) litre *0.001 m3Btuin/hft2 F (thermal
4、conductivity k) . 0.1442279 W/(mK) met 58.15 W/m2Btu/h . 0.2930711 W micron (m) of mercury (60F) 133 mPaBtu/hft2. 3.154591 W/m2mile . 1.609 kmBtu/hft2 F (overall heat transfer coefficient U) 5.678263 W/(m2K) mile, nautical *1.852 kmBtu/lb *2.326 kJ/kg mile per hour (mph) 1.609344 km/hBtu/lbF (specif
5、ic heat cp) *4.1868 kJ/(kgK) . 0.447 m/sbushel (dry, U.S.) . 0.0352394 m3millibar . *0.100 kPacalorie (thermochemical) *4.184 J mm of mercury (60F) 0.133 kPacentipoise (dynamic viscosity ) *1.00 mPas mm of water (60F) 9.80 Pacentistokes (kinematic viscosity ) *1.00 mm2/s ounce (mass, avoirdupois) 28
6、.35 gclo . 0.155 (m2K)/W ounce (force or thrust) 0.278 Ndyne 1.0 105N ounce (liquid, U.S.) 29.6 mLdyne/cm2. *0.100 Pa ounce inch (torque, moment) 7.06mNEDR hot water (150 Btu/h) 43.9606 W ounce (avoirdupois) per gallon. 7.489152 kg/m3EDR steam (240 Btu/h) 70.33706 W perm (permeance at 32F) 5.72135 1
7、011kg/(Pasm2)EER 0.293 COP perm inch (permeability at 32F) . 1.45362 1012kg/(Pasm)ft . *0.3048 m pint (liquid, U.S.) 4.73176 104m3*304.8 mm poundft/min, fpm *0.00508 m/s lb (avoirdupois, mass) 0.453592 kgft/s, fps *0.3048 m/s 453.592gft of water . 2989 Pa lbf(force or thrust) 4.448222 Nft of water p
8、er 100 ft pipe. 98.1 Pa/m lbf/ft (uniform load) 14.59390 N/mft20.092903 m2lb/fth (dynamic viscosity ) 0.4134 mPasft2h F/Btu (thermal resistance R) 0.176110 (m2K)/W lb/fts (dynamic viscosity ) 1490 mPasft2/s (kinematic viscosity ) 92,900 mm2/s lbfs/ft2(dynamic viscosity ) . 47.88026 Pasft328.316846 L
9、 lb/h 0.000126 kg/s0.02832 m3lb/min 0.007559 kg/sft3/min, cfm 0.471947 L/s lb/h steam at 212F (100C) 0.2843 kWft3/s, cfs. 28.316845 L/s lbf/ft2. 47.9 Paftlbf(torque or moment) . 1.355818 Nm lb/ft24.88 kg/m2ftlbf(work) 1.356 J lb/ft3(density ) 16.0 kg/m3ftlbf/lb (specific energy). 2.99 J/kg lb/gallon
10、 120 kg/m3ftlbf/min (power) 0.0226 W ppm (by mass) *1.00 mg/kgfootcandle . 10.76391 lx psi . 6.895 kPagallon (U.S., *231 in3) 3.785412 L quad (1015Btu). 1.055 EJgph 1.05 mL/s quart (liquid, U.S.) 0.9463 Lgpm. 0.0631 L/s square (100 ft2) . 9.2903 m2gpm/ft20.6791 L/(sm2) tablespoon (approximately) 15
11、mLgpm/ton refrigeration 0.0179 mL/J teaspoon (approximately) . 5 mLgrain (1/7000 lb). 0.0648 g therm (U.S.) 105.5 MJgr/gal. 17.1 g/m3ton, long (2240 lb) 1.016046 Mggr/lb 0.143 g/kg ton, short (2000 lb) . 0.907184 Mg; t (tonne)horsepower (boiler) (33,470 Btu/h) 9.81 kW ton, refrigeration (12,000 Btu/
12、h). 3.517 kWhorsepower (550 ftlbf/s) . 0.7457 kW torr (1 mm Hg at 0C) 133 Painch . *25.4 mm watt per square foot 10.76 W/m2in. of mercury (60F) 3.3864 kPa yd *0.9144 min. of water (60F) 248.84 Pa yd2. 0.8361 m2in/100 ft, thermal expansion coefficient. 0.833 mm/m yd3. 0.7646 m3To Obtain I-P By Divide
13、 SI To Obtain I-P By Divide SIThe preparation of this chapter is assigned to TC 1.6, Terminology.*Conversion factor is exact.Notes: 1. Units are U.S. values unless noted otherwise. 2. Litre is a special name for the cubic decimetre. 1 L = 1 dm3and 1 mL = 1 cm3.39.2 2017 ASHRAE HandbookFundamentals W
14、hen making conversions, remember that a converted value isno more precise than the original value. For many applications,rounding off the converted value to the same number of significantfigures as those in the original value provides acceptable accuracy.See ANSI Standard SI-10-1997 (available from
15、ASTM or IEEE)for additional conversions.Table 2 Conversion FactorsPressure psiin. of water (60F)in. Hg (32F) atmospheremm Hg (32F) bar kgf/cm2pascal1 = 27.708 = 2.0360 = 0.068046 = 51.715 = 0.068948 = 0.07030696 = 6894.80.036091 1 0.073483 2.4559 10-31.8665 2.4884 1032.537 103248.840.491154 13.609 1
16、 0.033421 25.400 0.033864 0.034532 3386.414.6960 407.19 29.921 1 760.0 1.01325* 1.03323 1.01325 105*0.0193368 0.53578 0.03937 1.31579 1031 1.3332 1031.3595 103133.3214.5038 401.86 29.530 0.98692 750.062 1 1.01972* 105*14.223 394.1 28.959 0.96784 735.559 0.980665* 1 9.80665 104*1.45038 1044.0186 1032
17、.953 1049.8692 1067.50 103105* 1.01972 105*1Mass lb (avoir.) grain ounce (avoir.) kg1 = 7000* = 16* = 0.453591.4286 1041 2.2857 1036.4800 1050.06250 437.5* 1 0.0283502.20462 1.5432 10435.274 1Volume cubic inch cubic foot gallon litre cubic metre (m3)1 = 5.787 104=4.329 103= 0.0163871 = 1.63871 10517
18、28* 1 7.48052 28.317 0.028317231.0* 0.13368 1 3.7854 0.003785461.02374 0.035315 0.264173 1 0.001*6.102374 10435.315 264.173 1000* 1Energy Btu ftlbfcalorie (cal)joule (J) =watt-second (Ws) watt-hour (Wh)Note: MBtu, which is 1000 Btu, is confusing and should not be used.1 = 778.17 = 251.9958 = 1055.05
19、6 = 0.2930711.2851 1031 0.32383 1.355818 3.76616 1043.9683 1033.08803 1 4.1868* 1.163 103*9.4782 1040.73756 0.23885 1 2.7778 1043.41214 2655.22 859.85 3600* 1Density lb/ft3lb/gal g/cm3kg/m31 = 0.133680 = 0.016018 = 16.0184637.48055 1 0.119827 119.82762.4280 8.34538 1 1000*0.0624280 0.008345 0.001* 1
20、Specific Volume ft3/lb gal/lb cm3/g m3/kg1 = 7.48055 = 62.4280 = 0.06242800.133680 1 8.34538 0.0083450.016018 0.119827 1 0.001*16.018463 119.827 1000* 1Viscosity (absolute) 1 poise = 1 dyne-sec/cm2= 0.1 Pas = 1 g/(cms)poise lbfs/ft2lbfh/ft2kg/(ms) = Ns/m2lbm/fts1 = 2.0885 103= 5.8014 107= 0.1* = 0.0
21、671955478.8026 1 2.7778 10447.88026 32.174051.72369 1063600* 1 1.72369 1051.15827 10510* 0.020885 5.8014 1061 0.067195514.8819 0.031081 8.6336 1061.4882 1Temperature Temperature Temperature IntervalScale K C R F K C R FKelvin x K = xx 273.15 1.8x 1.8x 459.67 1 K = 1 1 9/5 = 1.8 9/5 = 1.8Celsius xC =
22、 x + 273.15 x 1.8x + 491.67 1.8x + 32 1C = 1 1 9/5 = 1.8 9/5 = 1.8Rankine xR = x/1.8 (x 491.67)/1.8 xx 459.67 1R = 5/9 5/9 1 1Fahrenheit xF = (x + 459.67)/1.8 (x 32)/1.8 x + 459.67 x 1F = 5/9 5/9 1 1Notes: Conversions with * are exact.The Btu and calorie are based on the International Table.All temperature conversions and factors are exact.The term centigrade is obsolete and should not be used.
