Extech Instruments IR320 User Manual page 5

7. Emissivity Considerations
The Emissivity setting is shown in small digits at the lower left corner of the display. To adjust the Emissivity please refer
to the Emissivity Setting section. Emissivity represents the reflectivity of a material. Most organic materials and painted
or oxidized surfaces have an emissivity of approximately 0.95. Masking tape or flat black paint should be applied to
cover the measured surface. Wait a period of time to allow the tape or paint to reach thermal equilibrium with the
surface of the covered object. Measure the temperature of the surface covered with tape or paint only after
equilibrium has been achieved.
Measured Surfaces
Metals
Aluminum
Oxidization
A3003 Alloy
Oxidization
Rough
Brass
Burnishing
Oxidization
Copper
Oxidization
Electric Terminal Board
Hastelloy
Alloy
Inconel
Oxidization
Sand-Blasting
Electro Burnishing
Iron
Oxidization
Rusting
Iron (Casting)
Oxidization
Non-Oxidization
Casting
Iron (Forging)
Passivation
Lead
Rough
Oxidization
Molybdenum
Oxidization
Nickel
Oxidization
Platinum
Black
Steel
Cold rolling
Steel Plate Burnishing
Steel Plate Rubbing
Zinc
Oxidization
Table of Emissivity Factors for Common Materials
Emissivity
0.2-0.4
0.3
0.1-0.3
0.3
0.5
0.4-0.8
0.6
0.3-0.8
0.7-0.95
0.3-0.6
0.15
0.5-0.9
0.5-0.7
0.6-0.95
0.2
0.2-0.3
0.9
0.4
0.2-0.6
0.2-0.6
0.2-0.5
0.9
0.7-0.9
0.4-0.6
0.1
0.1
Measured Surfaces
Non-Metals
Asbestos
Asphalt
Basalt
Carbon
Non-Oxidization
Graphite
Silicon Carbide
Ceramics
Clay
Concrete
Cloth
Glass
Convex Glass
Smooth Glass
Lead-Boron Glass
Plates
Stone Products
Plaster
Ice
Limestone
Paper
Plastics
Water
Soil
Wood
5
Emissivity
0.95
0.95
0.7
0.8-0.9
0.7-0.8
0.9
0.95
0.95
0.95
0.9
0.76-0.8
0.92-0.94
0.78-0.82
0.96
0.93
0.8-0.95
0.98
0.98
0.95
0.95
0.93
0.9-0.98
0.9-0.95
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