6 Performing the measurement
25
Other materials can be imported into the instrument from an existing list
using the PC software.
Emissivity information:
The emissivity describes the capability of a body to emit electromagnetic
radiation. This is material-specific and must be adapted for correct
measurement results.
Non-metals (paper, ceramic, gypsum, wood, paints and coatings), plastics and
food have high emissivity, which means that the surface temperature can be
easily measured using infrared.
Because of their low or non-uniform emissivity, bright metals and metal oxides
only have limited suitability for infrared measurement. Highly inaccurate
measurements should be expected. A remedy for this is coatings that increase
emissivity, e.g. paint or emission adhesive (accessory: 0554 0051), which must
be applied to the object to be measured.
The following table gives typical emissivities of important materials. These
values can be used as a guide for user-defined settings.
Material (material temperature)
Emissivity
Aluminium, bright rolled (170 °C)
0.04
Cotton (20 °C)
0.77
Concrete (25 °C)
0.93
Ice, smooth (0 °C)
0.97
Iron, emery-ground (20 °C)
0.24
Iron with casting skin (100 °C)
0.80
Iron with rolling skin (20 °C)
0.77
Gypsum (20 °C)
0.90
Glass (90 °C)
0.94
Rubber, hard (23 °C)
0.94
Rubber, soft grey (23 °C)
0.89
Wood (70 °C)
0.94
Cork (20 °C)
0.70
Radiator, black anodised (50 °C)
0.98
Copper, slightly tarnished (20 °C)
0.04
Copper, oxidised (130 °C)
0.76
Plastics: PE, PP, PVC (20 °C)
0.94
Brass, oxidised (200 °C)
0.61
Paper (20 °C)
0.97
Porcelain (20 °C)
0.92
Black paint, matt (80 °C)
0.97
Steel, heat-treated surface (200 °C)
0.52
