Ⅵ
. Emissivity Adjustment
1. Emissivity
:
Emissivity is a value between 0 and 1 that
indicates an object’s ability to emit infrared energy,
Emissivity is determined primarily by the object’s
composition and surface finish.
The thermometer’s sensitivity to emissivity “
ε
” was set a
0.95 before shipment because the objects of 90% that
emissivity are around 0.95.
2.
Emissivity Adjustment
a). Apply black tape, black mat paint, or black magic marker
to the object if it is safe.
b). “
ε
” is set at 0.95 to measure the dark surface.
c). To aim the laser at dark surface, press
MEAS
button to
get measurement as T1.
d). Remove the black tape or black mat paint and aim laser
at the same area again then press
MEAS
button to get
the measurement as (T).
e). Change & reset a value for emissivity “
ε
” to get
measurement (T) until T equal to T1.
Emissivity VALUES (cont.)
Typical Emissivity Values-Metals (cont.)
SURFACE EMISSIVITY
Zinc (oxidized)
0.1*
Galvanized iron
0.3
Tin-plated steel
0.1*
Gold (polished)
0.1*
Silver (polished)
0.1*
Chromium (polished)
0.1*
Emissivity Values-Non-Metals
Refractory & Building Materials
Red brick (rough)
0.75 to 0.9
8
Fire clay
0.75
Asbestos 0.95
Concrete 0.7
Marble 0.9
Carborundum 0.85
Plaster 0.9
Alumina (fine grain)
0.25
Alumina (coarse grain)
0.45
Silica (fine grain)
0.4
Silica (coarse grain)
0.55
Zirconium silicate up to 500
℃
0.85
Zirconium silicate at 850
℃
0.6
Quartz (rough)
0.9
Carbon (graphite)
0.75
Carbon (soot)
0.95
Timber (various)
0.8 to 0.9
Miscellaneous
Enamel (any color)
0.9
Oil paint (any color)
0.95
Lacquer 0.9
Matte black paint
0.95 to 0.98
Aluminum lacquer
0.5
Water 0.98
Rubber (smooth)
0.9
Rubber (rough)
0.98
Plastics (various, solid)
0.8 to 0.95
Plastic films (05 mm thick)
0.5 to 0.95
Polythene film (03 mm thick)
0.2 to 0.3
Paper and cardboard
0.9
Silicone polish (03 mm thick)
0.7
* Emissivity vanes with punty
EMISSIVITY VALUES
Typical Emissivity Values-Metals
SURFACE EMISSIVITY
Iron and Steel
Cast iron (polished)
0.2
9
