Milwaukee Tool 2260-21NST - Manual (Page 20)

18 M12 160x120 Thermal Imager Operator’s Manual
Emissivity is the ratio of a target surface’s infrared output
(radiance) to that of a blackbody at the same temperature.
A “blackbody” is a theoretical perfect radiator of infrared
radiation (IR).
What this means is you can set the sensitivity of the
Thermal Imager to determine the true temperature of an
object, no matter what its IR radiation characteristics are.
The poorest radiators (surfaces with the lowest emissivity
ratios) need the most correction. These materials are things
like shiny metal and glass.
When you have a low-emissivity surface that you need
a very accurate temperature reading from, placing black
electrical tape or even painting it with flat-black paint is
very effective. Black electrical tape and flat-black painted
surfaces have an emissivity ratio of 0.95.
WARNING
To minimize the risk of electric shock, burn or
fire, never apply electrical tape or paint to an
electrically live surface. Always check to ensure
the power has been turned off before touching a
surface.
Emissivity
Press , select SETUP, then press to get the Setup
Menu as shown in Figure 7. Press and as necessary
to select “EMISSIVITY.” This brings up the Emissivity Menu
as shown in Figure 11.
0.95 DEFAULT
0.30 ALUMINUM
0.30 CUSTOM
EMISSIVITY
MATERIAL
Figure 11. Emissivity Menu
This setting tells the Thermal Imager what surface
material it is measuring. This is important, because
setting the right emissivity has a significant effect on the
accuracy of temperature readings. See Table 5 for a list
of the materials in the Thermal Imager Emissivity menu,
and their corresponding emissivity ratios. You can also
select “CUSTOM” in the emissivity menu, and select any
emissivity value. In Figure 11, “CUSTOM” shows “0.30,” but
when you select CUSTOM, you can choose any value.