Thermal Emissivity Values

Thermal emissivity is the measure of a material’s ability to emit infrared radiation, which is directly related to its temperature. It ranges from 0 to 1, where 1 indicates a perfect emitter (blackbody), and 0 means no emission. This property is important in heat transfer applications, as materials with higher thermal emissivity radiate heat more effectively. It depends on factors like surface texture, material composition, and temperature. Accurate knowledge of thermal emissivity is essential for thermal calculations, as it influences how much radiation a surface emits at a given temperature.

The Greek symbol “ε” (Epsilon) is commonly used to represent the emissivity value.

Emissivity values are not exact and are typically considered to be estimates. The values listed in the tables are compiled from a variety of sources.

You may also be interested in our Plate Infrared Radiation Calculator.

Thermal Emissivity - Metals

Material	Condition	Emissivity
Aluminium	Polished	0.04
Aluminium	Rolled	0.25
Aluminium	Unoxidised	0.04
Aluminium	Oxidised	0.25
Aluminium	Anodised Clear	0.77
Aluminium	Anodised Black	0.85
Aluminium	Chromate Conversion	0.2
Brass	Highly Polished	0.03
Brass	Oxidised	0.61
Copper	Polished	0.06
Copper	Oxidised	0.7
Iron	Polished	0.1
Iron	Oxidised	0.7
Iron	Heavily Rusted	0.93
Gold	Polished	0.06
Nickel	Polished	0.15
Nickel	Plating	0.12
Silver	Polished	0.03
Stainless Steel	Rolled	0.34
Stainless Steel	Polished	0.2
Stainless Steel	Oxidised	0.65
Steel	Rolled	0.7
Steel	Polished	0.15
Steel	Oxidised	0.79
Steel	Heavily Rusted	0.85
Steel	Galvanised (New)	0.24
Steel	Galvanised (old)	0.87

Thermal Emissivity - Building Materials

Material	Condition	Emissivity
Asphalt		0.9
Brick	Common Black	0.93
Brick	Common Red	0.87
Brick	Facing Red	0.87
Brick	Fireclay	0.75
Cement		0.9
Clay	Fired	0.91
Fibre Glass		0.75
Glass	Clear Untreated	0.85
Plaster Board		0.91
Tiles	Glazed	0.94
Wood	Planed	0.88
Wood	Oak	0.87
Wood	Pine	0.87
Wood	Mahogany	0.87
Wood	Cherry	0.84
Wood	Maple	0.87
Wood	Redwood	0.84
Wood	Walnut	0.84

Thermal Emissivity - Miscellaneous

Material	Condition	Emissivity
Carbon Fiber	Matte	0.9
Cardboard	Box	0.81
Ceramic		0.87
Charcoal	Powder	0.96
Human Skin		0.97
Ice		0.97
Paper	Black	0.9
Paper	White	0.68
Rubber	Black	0.93
Snow		0.85
Soil	Dry	0.92
Soil	Frozen	0.93
Soil	Wet	0.95

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