User Manual
94
It is therefore necessary to know the value of the emissivity. There is a vast amount of data
available, unfortunately much of it is confusing because substantially different values are
quoted. This is because emissivity depends upon:
a) The basic material
b) Surface condition - roughness and oxidation
c) Temperature
d) Angle of view
e) Wavelength
For materials with smooth, clean (unoxidised) surfaces, emissivities are usually in the range
0.05 to 0.50 and are usually very wavelength dependent, being higher at shorter wavelengths.
The appropriate settings for the
ThermoPro
TM
TP8S
IR Thermal Cameras are given in the
following tables. It must be remembered that these are only guideline figures. They can be
substantially increased if the surface is rough or even slightly oxidised.
The values quoted for oxidised metals assume that the metal is heavily oxidised. Thin oxide
layers will give an emissivity value between this and the value for an unoxidised surface.
If a more precise emissivity value is needed or more information is required on how to obtain
the emissivity value of a specific material, please contact: us.
