Hemispherical Emissivities of Various Surfaces Table

Heat Transfer Engineering

Hemispherical Emissivities of Various Surfaces Table

Material
Wavelength and Average Temperature
9.3 mm
310 K
5.4 mm
530 K
3.6 mm
800 K
1.8 mm
1700 K
0.6 mm
Solar
~6,000 K
Aluminum
polished
~0.04
0.05
0.08
~0.19
~0.30
oxidized
0.11
~0.12
0.18
-
-
24-ST weathered
0.40
0.32
0.27
-
-
surface roofing
0.22
-
-
-
-
anodized (at 1,000°F)
0.94
0.42
0.60
0.34
-
Brass
polished
0.10
0.10
-
-
-
oxidized
0.61
-
-
-
-
Chromium
polished
~0.08
~0.17
0.26
~0.40
0.49
Copper
polished
0.04
0.05
~0.18
~0.17
-
oxidized
0.87
0.83
0.77
-
-
Iron
polished
0.06
0.08
0.13
0.25
0.45
cast, oxidized
0.63
0.66
0.76
-
galvanized, new
0.23
-
-
0.42
-
galvanized, dirty
0.28
-
-
0.90
0.66
steel plate, rough
0.94
0.97
0.98
-
0.89
oxide
0.96
-
0.85
-
0.74
molten
-
-
-
0.3 – 0.4
-
Magnesium
0.07
0.13
0.18
0.24
0.30
Molybdenum filament
-
-
~0.09
~0.15
~0.20
Silver
polished
0.01
0.02
0.03
-
0.11
Stainless steel
18-8, polished
0.15
0.18
0.22
-
-
18-8, weathered
0.85
0.85
0.85
-
-
Steel tube
oxidized
-
0.94
-
-
-
Tungsten filament
0.03
-
-
~0.18
0.35
Zinc
polished
0.02
0.03
0.04
0.06
0.46
galvanized sheet
~0.25
-
-
-
-
Building and Insulating Materials
Asbestos paper
0.93
0.93
-
-
-
Asphalt
0.93
-
0.90
-
0.93
Brick
red
0.93
-
-
-
0.70
fire clay
0.90
~0.70
~0.75
-
-
silica
0.90
0.75
0.84
-
-
magnesite refractory
0.90
-
~0.40
-
Enamel, white
0.90
-
-
-
Marble, white
0.95
0.93
-
0.47
Paper, white
0.95
0.82
0.25
0.28
Plaster
0.91
-
-
-
Roofing board
0.93
-
-
-
-
Enameled steel, white
-
-
-
0.65
0.47
Asbestos cement, red
-
-
-
0.67
0.66
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