TESTO 835 Mode D'emploi page 22

22 13. Information on contact measurement
Because of their low or non-uniform emission level, blank metals and metal oxides are
only of limited use for IR measurement.
Coatings that increase the emission level, e.g. paint or emission adhesive (art. no.
0554 0051) must be applied to the measurement object. If this is not possible:
measure using a contact thermometer.
Emissivity table for important materials (typical values)
Material (Temperature)
Cotton (20°C/ 68°F)
Concrete (25°C/ 77°F)
Ice, smooth (0°C/ 32°F)
Iron, polished (20°C/ 68°F)
Iron with cast skin (100°C/ 212°F)
Iron with rolled skin (20°C/ 68°F)
Plaster (20°C/ 68°F)
Glass (90°C/ 194°F)
Rubber, hard (23°C/ 73°F)
Rubber, soft grey (23°C/ 73°F)
Wood (70°C/ 158°F)
Cork (20°C/ 68°F)
12.3 Measuring range, distance
Depending on the distance of the measuring instrument from the measurement object,
a specific measuring range is recorded.
Measuring lens (ratio of distance : measuring range)
In italics = laser
Not in italics = measuring range
13. Information on contact measurement
Observe the minimum penetration depth for immersion/penetration probes: 10x
probe diameter
Avoid using in aggressive acids or alkalis.
ε
Material (Temperature)
0.77 Heat sink, black anodised (50°C/ 122°F) 0.98
0.93 Copper, oxidised (130°C/ 266°F)
0.97 Plastics: PE, PP, PVC (20°C/ 68°F)
0.24 Brass, oxidised (200°C/ 392°F)
0.80 Paper (20°C/ 68°F)
0.77 Porcelain (20°C/ 68°F)
0.90 Black paint, matt (80°C/ 176°F)
0.94 Steel, heat-treated surface (200°C/ 392°F) 0.52
0.94 Steel, oxidised (200°C/ 392°F)
0.89 Clay, fired (70°C/ 158°F)
0.94 Transformer paint (70°C/ 158°F)
0.70 Brick, mortar, plaster (20°C/ 68°F)
ε
0.76
0.94
0.61
0.97
0.92
0.97
0.79
0.91
0.94
0.93