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Emissivity in the Infrared


Emissivity Table




Emissivity is a measure of a material’s radiating efficiency. An emissivity of 1.00 implies that the material is 100% efficient at radiating energy. An emissivity of 0.20 implies that the material radiates only 20% of that which it is capable of radiating.

Tables of emissivity values are only approximated values for real materials. A range of emissivity values is usually given for many materials whose emissivity can be affected by surface roughness or finish. Additionally, thin sheets of material such as plastics may be semi-transparent in the infrared and therefore have reduced emissivity.

To optimize the surface temperature measurement of a material:


Note: Applicable for material temperatures from 0 to 250°C

Alumel
Unoxidized
0.10 - 0.25
Oxidized
0.60
Oxidized
0.60
Aluminum
Polished
0.10 - 0.05
Oxidized
0.10 - 0.40
Rough
0.10 - 0.30
Anodized
0.60 - 0.95
Aluminum Oxide
0.40
Asbestos
0.95
Asphalt
0.90 - 1.00
Basalt
0.70
Bismuth
0.50
Brass
Polished
0.05
Oxidized
0.50 - 0.60
Burnished
0.30
Carbon
Unoxidized
0.40 - 0.90
Filament
0.50
Soot
0.50 - 0.95
Coke
0.95 - 1.00
Graphite
0.70 - 0.80
Carborundum
0.80 - 0.90
Ceramic
0.90 - 0.95
Clay
Fired
0.95
Concrete
0.95
Chromel
Oxidized
0.60 - 0.85
Chromium
0.10
Cobalt
0.20
Columbium
Polished
0.20
Oxidized
0.70
Copper
Polished
0.10
Oxidized
0.20 - 0.80
Electrical terminal blocks
0.60
Enamel
0.90
Foods
0.85 - 1.00
Formica
0.95
Mullite
0.80 - 0.85
Glass
Convex D
0.80
Nonex
0.80
Plate
0.90 - 0.95
Fused quartz
0.75
Pyrex, lead and soda
0.95
Gold
0.05
Granite
Polished
0.85
Rough
0.90
Natural
0.95
Gravel
0.90 - 0.95
Gypsum
0.85 - 0.95
Haynes Alloy
0.30 - 0.80
Human Skin
0.99
Inconel
Polished
0.15
Oxidized
0.70 - 0.95
Sandblasted
0.30 - 0.66
Iron
Polished
0.20
Oxidized
0.50 - 0.95
Rusted
0.50 - 0.70
Wrought, dull
0.90
Iron Oxide
0.85
Lacquer
Colored on Al
0.75 - 0.90
Colored
0.95
Clear on Al
0.10
Clear on Cu
0.65
Lead
Polished
0.05 - 0.10
Oxidized
0.30 - 0.65
Rough
0.40
Limestone
0.95 - 1.00
Magnesium Oxide
0.55
Molybdenum
Polished
0.05
Oxidized
0.20 - 0.80
Monel
Oxidized
0.45 - 0.85
Nichrome
Clean
0.65
Oxidized
0.60 - 0.85
Nickel
Polished
0.10
Oxidized
0.20 - 0.95
Nickel Oxide
0.60
Oil
Animal/vegetable
0.95 - 1.00
Mineral
0.90 - 1.00
0.001” thick
0.25
0.002” thick
0.46
0.005” thick
0.70
Paint
Aluminum paint
0.50
Bronze paint
0.80
Paint on metal
0.60 - 0.90
Paint on plastic or wood
0.80 - 0.95
Gold enamel
0.40
Clear silicone
0.65 - 0.80
Paper
0.85 - 1.00
Plaster
0.90
Plastic
0.95 - 1.00
Platinum
0.05
Polyester
0.75 - 0.85
Polyethylene
0.10
Quartz
0.90
Roofing Paper
0.90
Rubber
Hard glossy
0.95
Soft rough
0.85
Sand
0.80 - 0.90
Sandstone
0.70
Shale
0.70
Silica
Powder
0.35 - 0.60
Glazed
0.85
Unglazed
0.75
Silicone Carbide
0.80 - 0.95
Silver
0.05
Soil
Dry
0.90 - 0.95
Wet
0.95 - 1.00
Slate
0.70 - 0.80
Stainless Steel
Polished
0.10 - 0.15
Oxidized
0.45 - 0.95
Steel
Unoxidized
0.10
Oxidized
0.70 - 0.95
Cold Rolled
0.70 - 0.90
Ground sheet
0.40 - 0.60
Rough surface
0.95
Tantalum
Unoxidized
0.20
Oxidized
0.60
Textiles
Carpet
0.85 - 1.00
Close weave
0.70 - 0.95
Cotton
0.80
Leather
0.95 - 1.00
Silk
0.80
Died black
0.98
Tin
Unoxidized
0.05 - 0.10
Tungsten
Unoxidized
0.05
Filament
0.30
Water
Liquid
0.90 - 0.95
Ice
0.95 - 1.00
Snow
0.80 - 1.00
Wood
Planed
0.80 - 0.95
Sawdust
0.75
Zinc
Polished
0.05
Oxidized
0.10
Galvanized
0.20 - 0.30


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