Operation
Manual
21
Raytek
CM
N
ON
-M
ETAL
Material
Emissivity (
Spectral range 8~14
µm)
Asbestos 0.95
Asphalt
0.95
Basalt
0.7
Carbon
Unoxidized
0.8-0.9
Graphite
0.7-0.8
Carborundum
0.9
Ceramic 0.95
Clay 0.95
Concrete
0.95
Cloth 0.95
Glass
Plate
0.85
“Gob”
—
Gravel 0.95
Gypsum 0.8-0.95
Ice 0.98
Limestone 0.98
Paint (non-al.)
0.9-0.95
Paper (any color)
0.95
Plastic (opaque, over 20 mils)
0.95
Rubber 0.95
Sand 0.9
Snow
0.9
Soil
0.9-0.98
Water 0.93
Wood, Natural
0.9-0.95
Table 6: Typical Emissivity Values
To
optimize
surface
temperature
measurements,
consider
the
following
guidelines:
z
Determine the object emissivity using the instrument that will also be used for the measurements.
z
Avoid reflections by shielding the object from surrounding temperature sources.
z
For higher temperature objects, use instruments with the shortest wavelength possible.
z
For translucent materials, such as plastic foils or glass, assure that the background is uniform and lower in
temperature than the object.
1.888.475.5235
