GE HumiLab Operator's Manual page 74

70
Page
Water vapor content expressed as parts per million by volume is
given by the following:
Expressing water vapor content as parts per million by weight (or
mixing ratio) requires multiplication of the above by the ratio of
the molecular weight of water to that of air as given by the
following:
PPM W
See Figure 16 for a graphical conversion chart and Figure 17 for a
Psychrometric chart.
6 e T d
=
PPM V 10
--------------------- -
P e T d
–
6
e
=
0.622 × 10
---------- -
P e
–
Appendix D — Humidity Equations and Conversion
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