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Moist Air - Weight of Water Vapor

Weight of water vapor in air

Grains of moisture per pound of dry air at standard atmospheric pressure at relative humidity ranging 10 - 90% are indicated below.

Moist Air - Weight of Water Vapor
Relative Humidity
(%) 		Water Vapor in Air (grains* water vapor per pound dry air)
Temperature
(oC)
-14101621273238
(oF)
30405060708090100
10 3 4 6 8 11 16 21 29
20 5 7 10 16 21 30 42 58
30 7 11 14 22 34 46 65 87
40 9 14 20 30 44 62 85 116
50 12 18 26 39 55 78 108 147
60 14 22 32 48 66 92 128 176
70 17 26 38 54 78 108 152 208
80 19 29 42 62 88 125 173 -
90 21 33 48 70 100 140 190 -

*grains of water is commonly used in psychrometrics

  • 1 grain = 0.000143 lbm = 0.0648 g  (7000 grains per lbm)

Moist air - weight of water in air - diagram

Same table as above with water vapor in "pounds water vapor per pound dry air".

Moist Air - Weight of Water Vapor
Relative Humidity
(%) 		Water Vapor in Air (pounds water vapor per pound dry air)
Temperature
(oC)
-14101621273238
(oF)
30405060708090100
10 0.0004 0.0006 0.0009 0.0011 0.0016 0.0023 0.0030 0.0041
20 0.0007 0.0010 0.0014 0.0023 0.0030 0.0043 0.0060 0.0083
30 0.0010 0.0016 0.0020 0.0031 0.0049 0.0066 0.0093 0.0124
40 0.0013 0.0020 0.0029 0.0043 0.0063 0.0089 0.0122 0.0166
50 0.0017 0.0026 0.0037 0.0056 0.0079 0.0112 0.0154 0.0210
60 0.0020 0.0031 0.0046 0.0069 0.0094 0.0132 0.0183 0.0252
70 0.0024 0.0037 0.0054 0.0077 0.0112 0.0154 0.0217 0.0297
80 0.0027 0.0041 0.0060 0.0089 0.0126 0.0179 0.0247 -
90 0.0030 0.0047 0.0069 0.0100 0.0143 0.0200 0.0272 -

Related Topics

  • Air Psychrometrics

    Moist and humid air calculations. Psychrometric charts and Mollier diagrams. Air-condition systems temperatures, absolute and relative humidities and moisture content in air.

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