testo 830-T3 Bedienungsanleitung Seite 14

14 11. Information on infrared measurement
Apply emissivity enhancing layers such as varnish or emission
adhesive tape (Item no. 0554 0051) to the object being
measured. If this is not possible, measure with the contact
thermometer.
Emissivity table of the most important materials
(typical values)
Material (Temperature)
Aluminium, bright-rolled (170°C/338°F) 0.04
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)
11.3 Measurement spot, Distance
A specific spot is determined depending on the distance from the
measuring instrument to the object being measured.
Measurement optics (Ratio Distance : Measurement spot)
testo 830-T3
Ø 16 mm
Ø 2 mm
25 mm
500 mm
ε
Material (Temperature)
Heat sink, black anodised (50°C/122°F) 0.98
0.77 Copper, lightly tarnished (20°C/68°F)
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)
0.94
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)
Ø 190 mm
1000 mm
2000 mm
Laser
Ø 792 mm
Ø 390 mm
Laser
ε
0.04
0.76
0.94
0.61
0.97
0.92
0.97
0.52
0.79
0.91
0.94
0.93