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MAN-SYSTEMS INTEGRATION STANDARDS VOLUME 1 VOLUME 2 SEARCH CONTACT US

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MAN-SYSTEMS INTEGRATION STANDARDS
FOREWORD
BIBLIOGRAPHY
REFERENCES
GLOSSARY
ABBREVIATIONS
UNITS OF MEASURE AND CONVERSION FACTORS
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MAN-SYSTEMS INTEGRATION STANDARDS Print this page Click to print the page

Appendix E - Units of Measure and Conversion Factors

Skip Alphabetical Shortcut Links| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |

USER'S GUIDE

This section presents definitions, physical constants and conversion factors that are used in the text and may be useful as reference data. Scroll down through the list or use the alphabetical links below to go directly to the section where your word or symbol is located.

A Skip to B

ATMOSPHERE (atm): 

The pressure exerted by 76 cm mercury with a density of 13.5951 gm/cm3 at 1g (the standard barometric pressure at sea level).

1 atm        = 325 x 106 dynes/cm 2

1 atm        = 1033.2 gm/cm 2

1 atm        = 760 mm Hg

1 atm        = 14.696 psi

1 atm        = 101.329 kPa (kilo Pascals)

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B Skip to C

BRITISH THERMAL UNIT (Btu):

1 Btu        = 1.0559 x 1010 ergs

1 Btu        = 1055.9 joules

1 Btu        = 251.995 gm-cal

1 Btu        = 778.77 ft-lbs

1 Btu        = 0.25199 kcal

1 Btu/hr        = 0.1667 Btu/min 

1 Btu/hr        = 0.04199 kcal/min

1 Btu/hr        = 0.2932 watt

1 Btu/min        = 0.25199 kcal\min

1 Btu/min        = 0.23599 hp

1 Btu/min        = 17.595 watts

1 Btu/ft2, hr        = 2.7125 kcal/m2 hr

 

Btu/hr to joules:

1 Btu/hr  = 1.05435 x 103 joule/hr

800 Btu/hr x 1054.35 = 843480 joule/hr

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C Skip to D

CANDELA (cd):

1 cd                    = 1.018 candle

CANDLE (c):  

The unit of luminous intensity.

1 c                      = 1 lumen/steradian

CELSIUS (°C):

(See Degrees Centigrade)

CENTIGRADE (°C):

(See Degrees Centigrade)

CENTIMETER (cm):   

(See also Square Centimeter, Cubic Centimeter).

1 cm        = 0.03280 ft

1 cm        = 0.3937 in

1 cm        = 0.01 m

1 cm        = 10mm

1 cm        = 1x104m (micron)

CENTIMETER-CANDLE (phot):

1 phot                 = 1 x 104 lux

CENTIMETERS PER SECOND PER SECOND:

1 cm/sec2            = 0.0328 ft/sec2

CLO (clo):

The unit of insulation resistance for clothing.

1 clo    = 0.18°C m2hr/kcal

1 clo    = 0.88°F ft2hr/Btu

CUBIC CENTIMETER (cc or cm3):

1 CC    = 3.531 x 10-5 ft3

1 CC    = 0.061023 in3

1 CC    = 1 x 10-6 m3

1 CC    = 1000 mm3

1 CC    = 2.6417 x 10-4 gal (US fluid)

1 CC    = 0.0338 oz (US fluid)

1 CC    = 2.113 x 10-3 pint (US fluid)

1 cc/sec    = 0.0021186 ft3/min

CUBIC FOOT

1 ft3    = 1728 in3

1 ft3    = 28.32 liters

1 ft3    = 0.02832 m3

1 ft3/min    = 472.0 cc/sec

1 ft3/min    = 0.4720 liter/sec

1 ft3/min    = 62.43 lbs H2O/min

1 ft3/sec    = 1699.3 liters/min

CUBIC INCH:

1 in3    = 5.787 x 10-4 ft3

1 in3    = 1.639 x 102 liter

1 in3    = 1.639 x 10-5 m3

CUBIC METER:

1 m3    = 35.3144 ft3

1 m3    = 6.1023 x 104 in3

1 m3    = 999.973 liters

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D Skip to E

DECIBEL (db):  

Used for comparing power levels, acoustical or electrical.  (See also Sound Pressure Level).

1 db    = 10 log10 P/PO 

    where P is the power to be compared to a reference power PO

1 db    = 1 bel is equal to an increase in power (P) by a factor of 10

DEGREE (ANGULAR) (deg):

1 deg    = 60 minutes

1 deg    = 0.01745 radian

1 deg    = 3600 seconds

1 deg    = 1.7453 X 10-2 steradian --- note, this is changed from the original version that contains an error

DEGREES TO RADIANS:

1 deg     = π/180 rad

60° x π/180 = 1.0472  = 1 rad

DEGREES CENTIGRADE (°C):

°C    = 5/9 * (°F - 32)

DEGREES FAHRENHEIT (°F):

°F    = (9/5 * °C) + 32

DEGREES PER SECOND:

1 deg/sec    = 0.017453 radian/sec

1 deg/sec    = 0.1667 rpm

DYNE (dyne):

1 dyne    = 1.0197 x 10-6 kg

1 dyne    = 2.2481 x 10-6 lb

1 dyne-cm    = 1 erg

DYNE PER SQUARE CENTIMETER

1 dyne/cm2    = 9.8692 x 10-7 atm

1 dyne/cm2    = 0.0010197 gm/cm2

1 dyne/cm2    = 4.0148 x 10-4 in H2O

1 dyne/cm2    = 7.5006 x 10-4 mm Hg

1 dyne/cm2    = 1.4504 x 10-5 psi

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E Skip to F

ERG (erg):

1 erg    = 9.4805 x 10-11 Btu

1 erg    = 7.3756 x 10-8 ft-lb

1 erg    = 2.3889 x 10-11 kcal

1 erg    = 8.8510 x 10-7 lb-in

1 erg    = 1 dyne-cm

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F Skip to G

FAHRENHEIT (°F):

(See Degrees Fahrenheit).

FOOT (ft):  

(See also Square Foot, Cubic Foot).

1 ft    = 30.48 cm

1 ft    = 12 in

1 ft    = 0.3048 m

FOOT-CANDLE (fc):

1 ft-c    = 1 lumen/ft2

1 ft-c    = 10.764 lumen/m2

1 ft-c    = 10.75 lux

FOOT-LAMBERT (ft-L):

1 ft-L    = 1.0764 millilamberts

1 ft-L    = 0.32 decibels with respect to 1 mL

FOOT PER MINUTE

1 ft/min    = 0.3048 m/min 

1 ft/min    = 0.005080 m/sec

1 ft/min    = 0.011364 mph

FOOT PER SECOND:

1 ft/sec    = 1.0973 km/hr

1 ft/sec    = 0.5921 knot

1 ft/sec    = 0.6818 mph

FOOT-POUND (ft-lb):

1 ft-lb    = 0.001285 Btu

1 ft-lb    = 1.3558 x 107 ergs

1 ft-lb    = 3.2389 x 10-4 kcal

1 ft-lb/min    = 3.0303 x 10-5 hp

1 ft-lb/min    = 0.01667 ft-lb/sec

1 ft-lb/min    = 0.022597 watt

1 ft-lb/sec    = 0.001818 hp

1 ft-lb/sec    = 0.01943 kcal/min

1 ft-lb/sec    = 1.3558 watts

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G Skip to H

G (g):

The acceleration of gravity (also the acceleration of a vehicle).

1g = 9.81 m/s2

1 ft/sec    = 1.0973 km/hr

1 ft/sec    = 0.5921 knot

1 ft/sec    = 0.6818 mph

GRAM (gm): 

1 gm    = 0.001 kg

1 gm    = 1000 mg

1 gm    = 0.03527 oz

1 gm    = 0.0022046 lb

1 gm/cm3    = 62.428 lbs/ft3

1 gm/hr    = 0.540 lb/day

1 gm/hr    = 0.0003757 lb/min

1 gm/liter    = 0.062427 lb/ft3

1 gm/cm2    = 9.6784 x 10-4 atm

1 gm/cm2     = 980.665 dynes/cm2

1 gm/cm2     = 0.9356 mm Hg

1 gm/cm2     = 0.014223 psi

1 gm/m2/hr    = 2.78 x 10-5 gm/cm2/sec

1 gm/m2/hr    = 0.7448 lb/ft2/hr

GRAM-CALORIE (gm-cal): 

1 gm-cal    = 30874 ft-lbs

1 gm-cal    = 0.001 kcal

GRAY (Gy):  

The International System of Units (SI) unit for the amount of ionizing radiation energy absorbed by tissue.

1 Gy              = 100 rads

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H Skip to I

HORSEPOWER (hp):

1 hp    = 3.300 x 104 ft-lbs/min

1 hp    = 550 ft-lbs/sec

1 hp    = 10.688 kcal/min

1 hp    = 745.7 watts

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I Skip to J

INCH (in):  

(See also Cubic Inch, Square Inch)

1 in    = 2.540 cm

1 in    = 0.0833 ft

1 in    = 25.40 mm

INCH OF WATER (in H2O):

1 in H2O  (at 4°C)    = 0.002458 atm

1 in H2O  (at 4°C)    = 2490.82 dynes/cm2

1 in H2O  (at 4°C)    = 0.0361 psi

1 in H2O (at 4°C)    = 1.868 mm Hg

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J Skip to K

JOULE (joule):

1 joule               = 1 watt-sec

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K Skip to L

KILOGRAM (kg):

1 kg    = 1000 gm

1 kg    = 2.205 lb

1 kg    = 35.28 oz

KILOGRAM-CALORIE (kcal or large Calorie):

1 kcal    = 3.9683 Btu

1 kcal    = 4.186 x 1010 ergs

1 kcal    = 1000 gm-cal

1 kcal    = 3087 ft-lbs

1 kcal/hr    = 0.0661 Btu/min

1 kcal/hr    = 0.857 ft-lbs/sec

1 kcal/hr    = 0.1667 kcal/min

1 kcal/hr    = 1.161 watts

1 kcal/m2hr    = 0.3687 Btu/ft2hr

1 kcal/min    = 3.9685 Btu/min

1 kcal/min    = 51.457 ft-lbs/sec

1 kcal/min    = 0.093557 hp

1 kcal/min    = 69.767 watts

KILOGRAM-CENTIMETER SQUARED:

1 kg-cm2    = 0.3417 lb-in2

KILOGRAM-METER PER SECOND:

1 kg-m/sec    = 7.2330 ft-lb/sec

1 kg-m/sec    = 9.80665 watts

KILOMETER (km):

1 km    = 105 cm

1 km    = 3281 ft

1 km    = 103 meters, m

1 km    = 0.6214 statute miles, mi

1 km    = 0.54 nautical miles, nm

KILOPASCAL:

1kPa    = 6.895 psi

1kPa    = 4.754 x 105 dynes/cm2

1 psi    = 0.145 kPa

KILOMETERS PER HOUR:

1 km/hr    = 0.9113 ft/sec

1 km/hr    = 0.5396 knot

1 km/hr    = 0.6214 mph

KNOT (nautical mile per hour):

1 knot    = 1.689 ft/sec

1 knot    = 1.853 km/hr

1 knot    = 1.1516 mph

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L Skip to M

LAMBERT (L):  Unit of surface brightness.

1L    = 0.3183 c/cm2

1L    = 2.0536 c/in2

1L    = 1 lumen/cm2

LITER (l):

1 liter    = 0.03531 ft3

1 liter    = 61.02 in3

1 liter    = 1000 ml

1 liter/min    = 5.886 x 10-4 ft3/sec

1 liter/sec    = 2.12 ft3/min

LUMEN (lumen):

1 lumen    = 0.001496 watt

1 lumen    = 0.07958 spherical candle power

1 lumen/ft2    = 1 ft-c

1 lumen/ft2    = 10.764 lumen/m2

LUMENS PER SQ. METER TO FT CANDLES:

1 lumen/m2    = 0.0929 ft. candle

LUX:

1 lux    = 0.093 ft-c (see meter-candle)

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M Skip to N

METER (m):

(See also Cubic Meter).

1m    = 100 cm

1m    = 3.281 ft

1m    = 39.37 in

METER-CANDLE (lux):

1 lux    = 1 lumen/m2

1 lux    = 0.092903 ft-c

METER PER SECOND (m/sec):

1 m/sec    = 3.281 ft/sec

1 m/sec    = 3.600 km/hr

1 m/sec    = 2.2369 mph

MICRON (μ or mu):  

A unit of length equal to one-millionth of a meter or one-thousandth of a millimeter, usually called micrometer.

1 μ    = 10-6 meter

1 μ    = 3.937 x 10-5 in

1 μ    = 0.001 mm

MIL (mil):

1 mil    = 0.001 in

1 mil    = 0.0254 mm

1 mil    = 25.40μ (microns)

MILES (statute) (mi):

1 mi    = 1,609 x 105 cm 

1 mi    = 5,280 ft

1 mi    = 1.609 km

MILES PER HOUR (mph)

1 mph    = 88 ft/min

1 mph    = 1.4667 ft/sec

1 mph    = 1.6093 km/hr

1 mph    = 0.8684 knot

MILLIGRAM (mg):

1 mg    = 0.001 gm

1 mg    = 3.5274 x 10-5 oz

1 mg    = 2.2046 x 10-6 lb

1 mg/m3    = 6.243 x 10-4 lb/ft3

MILLILAMBERT (ml):  

(perfectly diffused light)

1 mL    = 0.929 lumen/ft2

MILLILITER (ml):

1 ml    = 1.000028 cc

1 ml    = 0.061025 in3

1 ml    = 0.001 liter

1 ml    = 0.0338 oz (US fluid)

MILLILITERS PER HOUR:

1 ml/hr    = 0.06102 in3/hr

MILLIMETER(mm):

(See also Square Millimeter)

1mm    = 0.10 cm

1mm    = 0.03937 in

1mm    = 1000 μ

MILLIMETER OF MERCURY (mm Hg):

1mm Hg (at 0°C)    = 0.0013158 atm

1mm Hg (at 0°C)    = 1333.22 dyne/cm2

1mm Hg (at 0°C)    = 1.3595 gm/cm2

1mm Hg (at 0°C)    = 0.019337 psi

1mm Hg (at 0°C)    = 0.535 in H2O

1mm Hg (at 0°C)    = 0.1333 kPa

    

MILLISECONDS (msec):

1 msec              = 0.001 sec

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N Skip to O

NAUTICAL MILES (nm):

1 nm    = 0.87 statute miles

1 nm    = 1.85 kilometers

NEWTONS TO POUNDS:

1 N           = 0.22507 lbf

NEWTON CENTIMETERS TO INCH OUNCES:

1 N-cm     = 1/.706 in oz

70N-cm x 1/.706  = 99.15    = 100 in oz

NEWTON METERS TO FOOT POUNDS:

1Nm    = 1/1.356 ft lb

15Nm x 1/1.356    = 11.06    = 11 ft lb

NEWTON METERS TO INCH POUNDS:

1 Nm    = 1/.11298 in lb

4 Nm x 1/.11298      = 35.4      = 3 5 in lb

NIT:

Unit of luminance equal to the luminance provided by one candle of radiant flux emitted per square meter of surface - candela per square meter (Cd m2).

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O Skip to P

OUNCE (oz):

1 oz     = 28.3495 gm

1 oz     = 0.0625 lb

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P Skip to Q

PASCALS (Pa)

Pa    = 4.75389 dynes/cm2

Pa    = 6.895 x 10-3 psi

PARTS PER MILLION (ppm).

1 ppm    = 1.0 mg/liter of H2O

1 ppm    = 8.345 lbs/million gallons

PHON (phon):

1 phon unit    = SPL of a 1000 cycle/sec tone

PHOT:  

(See Centimeter Candle)

Physical Constants:

    Acceleration of gravity (g) 

    = 32.17 ft/sec2= 980.6 cm/sec2

    Avogradro's number (N)

    = 6.0221367 x 1023 molecules/gram-mole

    Density of air at 0°C and 760 mm Hg

    = 0.0012929 grams/cm3(0.0807 lb/ft3)

    Density of water at 0°C

    = .099984 grams/cm3

    Heat of fusion of water at 1.0 atm

    = 79.7 calories/gram = 144 Btu/pound

    Heat of vaporization of water at 1.0 atm

    = 540 calories/gram = 970 Btu/pound

    Naperian-logarithm base

    = 2.71828183

    Pi (π)

    = 3.14159265

    Specific heat of air

    = Cp = 0.238 cal/gram (°C)

    Velocity of light (c)

    = 2.99792458 x 1010 cm/sec

    Velocity of sound in dry air at 0°C, 1 atm

    = 33,136 cm/sec = 1,089 feet/sec

POISE: Unit of viscosity.

1 poise    = 1 dyne/sec, cm2

1 poise    = 1 gm/cm, sec

1 poise    = 0.067196 lb/ft, sec

POUND (lb):

1 lb    = 453.5924 gm

1 lb    = 0.45359 kg

1 lb    = 16 oz

1 lb    = 4.448 N

1 lb/day    = 18.89 gm/hr

1 lb/hr    = 0.7559 gm/min

1 lb/hr    = 10.886 kg/day

POUND-INCH (lb-in):

1 lb-in    = 1.1298 x 106 dyne/cm 

POUND-INCH SQUARED:  

Unit of moment of inertia

1 lb-in2    = 2.9264 kg-cm2

POUND OF WATER PER MINUTE (lb H2O/min):

1 lb H2O/min    = 0.01603 ft3/min

1 lb H2O/min    = 2.670 x 10-4 ft3/sec

POUND PER CUBIC FOOT (lb/ft3):

1 lb/ ft3    = 0.01602 gm/ cm3

POUNDS PER SQUARE INCH (psi):

1 psi    = 0.06805 atm

1 psi    = 6.8947 x 104 dyne/cm2

1 psi    = 70.307 gm/cm2

1 psi    = 51.715 mmHg

1 psi    = 27.7 in H2O

1 psi    = 145.03 Pa

POUNDS PER SQUARE INCH ABSOLUTE (psia):

Absolute pressure, where 0 psia = vacuum

1 psia    = 0.1449 kpascals

POUND WEIGHT (1 wt):

1 lb wt    = 4.4482 x 105 dynes

1 lb wt    = 453.59 gm wt

1 lb wt    = 16 oz

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Q Skip to S

none

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R Skip to S

RAD (rad):

Radiation absorbed dose.

1 rad     = 100 ergs/gm of irradiated material

RADIAN (rad):

1 radian    = ½π circumference revolution (0.15915)

1 radian    = 57.296 deg

1 radian/sec    = 57.296 deg/sec

1 radian/sec    = 9.549 rpm

1 radian/sec2    = 572.96 rpm2

REVOLUTIONS PER MINUTE (rpm):

1 rpm    = 6 deg/sec

1 rpm    = 0.10472 radian/sec

1 rpm2    = 0.001745 radian/sec2

ROENTGEN (r):

1 r    = ionization by x-rays or gamma-rays producing 1 electrostatic unit of charge in 1 cm3 of air (STP)

1 r    = 83.0 ergs/gm

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S Skip to end

SIEVERT (Sv):

Sv is the International System of Units (SI) unit for ionizing radiation dose equivalent. (Refer to Figure 5.7.2.1.3.1-1 for definition of Q values)

1 Sv    = 100 rem = (Gy) (Q)

SOUND PRESSURE LEVEL (SPL):

SPL is sound pressure related logarithmically to a reference level of pressure (Po), which by convention is 0.0002 dynes/cm2. The defining equation is:

SPL     = 20 log10 P/PO in decibels

SQUARE CENTIMETER (cm2):

1 cm2    = 1.076 x 10-3 ft2

1 cm2    = 0.1550 in2

1 cm2    = 100 mm2

SQUARE FOOT (ft2):

1 ft2    = 929.0304 cm2

1 ft2      = 144 in2

SQUARE INCH (in2):

1 in2    = 6.4516 cm2

1 in2    = 0.006944 ft2

1 in2    = 645.1626 mm2

SQUARE MILLIMETER (mm2):

1 mm2    = 0.01 cm2

1 mm2    = 0.001550 in2

STERADIAN:

The solid angle which encloses a surface on a sphere equal to the square of the radius.

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