A study of variations in IR absorption characteristics of fabrics with mois
ture regain and fiber type is discussed. Infrared spectral absorptivities o
f fabrics are measured over the range of wavelengths from 0.7 to 25 microns
. These values are used with the normalized emission characteristics of bla
ckbody emitters to calculate average absorptivities for blackbody emitter t
emperatures ranging from 500 to 3000 K. Overall radiant efficiencies of the
blackbody emitters are calculated by multiplying average absorptivities by
the radiant efficiencies of emitters in converting input power to IR radia
nt output power. The absorption characteristics of several fabrics such as
polypropylene and wool are measured so that the behavior of hydrophilic and
hydrophobic fibers can be compared. Correlation equations are presented fo
r average absorptivities of several fabrics as a function of moisture regai
n.