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9
Emissivity
Emissivity is a term used to describe the energy-emitting characteristics of
materials. Most (90% of typical applications) organic materials and painted
or oxidized surfaces have an emissivity of 0.95 (pre-set in the unit).
Inaccurate readings will result from measuring shiny or polished metal
surfaces. To compensate, cover the surface to be measured with masking
tape or flat black paint. Allow time for the tape to reach the same
temperature as the material underneath it. Measure the temperature of the
tape or painted surface.
Emissivity Values
Substance
Thermal
Emissivity
Substance
Thermal
Emissivity
Asphalt
0.90 to 0.98
Cloth (black)
0.98
Concrete
0.94
Human skin
0.98
Cement
0.96
Lather
0.75 to 0.80
Sand
0.90
Charcoal (powder)
0.96
Earth
0.92 to 0.96
Lacquer
0.80 to 0.95
Water
0.92 to 0.96
Lacquer (matt)
0.97
Ice
0.96 to 0.98
Rubber (black)
0.94
Snow
0.83
Plastic
0.85 to 0.95
Glass
0.90 to 0.95
Timber
0.90
Ceramic
0.90 to 0.94
Paper
0.70 to 0.94
Marble
0.94
Chromium oxides
0.81
Plaster
0.80 to 0.90
Copper oxides
0.78
Mortar
0.89 to 0.91
Iron oxides
0.78 to 0.82
Brick
0.93 to 0.96
Textiles
0.90
