KCTE-80
Thermal Imager
www.grupotemper.com
6.10-Temperature Measurement
All objects radiate infrared energy. The quantity of energy radiated is base on the actual surface temperature
and the surface emissivity of the object. The Thermal Imager senses the infrared energy from the surface of the
object and uses this data to calculate an estimated temperature value. Many common objects and materials such as
painted metal, wood, water, skin, and cloth are very good at radiating energy and it is easy to get relatively
accurate measurements. For surfaces that are good at radiating energy (high emissivity), the emissivity factor
is >=0.90. This simplification does not work on shiny surfaces or unpainted metals as they have an emissivity of
<0.6. These materials are not good at radiating energy and are classified as low emissivity. To more accurately
measure materials with a low emissivity, an emissivity correction is necessary. Adjustment to the emissivity
setting will usually allow the Thermal Imager to calculate a more accurate estimate of the actual temperature.
More information please see Emissivity Adjustment to get the most accurate temperature measurements.
6.11-Emissivity Adjustment
The correct emissivity value is important to make the most accurate temperature measurement. Emissivity of
a surface can have a large effect on the apparent temperatures that the Thermal Imager observes. Understanding
the emissivity of the surface, but may not always, allow you to obtain more accurate temperature measurements.
Note
Surfaces with an emissivity of <0.60 make reliable and consistent determination of actual temperature
problematic. The lower the emissivity, the more potential error is associated with the Imager‟s temperature
measurement calculations. This is also true even when adjustments to the emissivity and reflected background
adjustments are performed properly.
Emissivity is set directly as a value or from a list of emissivity values for some common materials. The
global emissivity displays in LCD Screen as E=x.xx.
The following table gives typical emissivity of important materials.
Material
Emissivity
Water
0.96
Stainless steel
0.14
Aluminum plate
0.09
Asphalt
0.96
Concrete
0.97
Cast iron
0.81
Rubber
0.95
Wood
0.85
Brick
0.75
Tape
0.96
Brass plate
0.06
Human skin
0.98
PVC plastic
0.93
Polycarbonate
0.80
Oxidized copper
0.78
Rust
0.80
Paint
0.90
Soil
0.93
