Omega Engineering OMEGASCOPE OS533E User Manual download pdf (Page 72)

B-1

Appendix: Emissivity Values

B

Table B-1 provides guidelines for estimating the emissivity of various

common materials. Actual emissivity, especially of metals, can vary

greatly depending upon surface finish, oxidation, or the presence of

contaminants. Also, emissivity or infrared radiation for some materials

varies with wavelength and temperature. To determine the exact

emissivities for most applications, follow the procedures in Appendix C.

Table B-1. Emissivity Table

METALS

Material Emissivity (ε)

Aluminum – pure highly polished plate . . . . . . . . . . . . . . . . . . . . 0.04 to 0.06

Aluminum

– heavily oxidized . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 0.31

Aluminum

– commercial sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.09

Brass

– dull plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.22

Brass

– highly polished, 73.2% Cu, 26.7% Zn . . . . . . . . . . . . . . . . . . . . . 0.03

Chromium

– polished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.08 to 0.36

Copper

– polished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05

Copper

– heated at 600°C (1110°F) . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.57

Gold

– pure, highly polished or liquid . . . . . . . . . . . . . . . . . . . . 0.02 to 0.04

Iron and steel (excluding stainless)

– polished iron . . . . . . . . . . . . 0.14 to 0.38

Iron and steel (excluding stainless)

– polished cast iron . . . . . . . . . . . . . . 0.21

Iron and steel (excluding stainless)

– polished wrought iron . . . . . . . . . . . 0.28

Iron and steel (excluding stainless)

– oxidized dull wrought iron . . . . . . . . 0.94

Iron and steel (excluding stainless)

– rusted iron plate . . . . . . . . . . . . . . . 0.69

Iron and steel (excluding stainless)

– polished steel . . . . . . . . . . . . . . . . . 0.07

Iron and steel (excluding stainless)

– polished steel oxidized at

600°C (1110°F) . . . . . . . . . . . . . . . 0.79

Iron and steel (excluding stainless)

– rolled sheet steel . . . . . . . . . . . . . . . 0.66

Iron and steel (excluding stainless)

– rough steel plate . . . . . . . . . 0.94 to 0.97

Lead

– gray and oxidized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.28

Mercury

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.09 to 0.12

Molybdenum filament

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.10 to 0.20

Nickel

– polished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.07

Nickel

– oxidized at 649 to1254°C (1200°F to 2290°F) . . . . . . . 0.59 to 0.86

Platinum

– pure polished plate . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05 to 0.10

Platinum

– wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.07 to 0.18

Silver

– pure and polished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.02 to 0.03

Stainless steel

– polished . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.07

Stainless steel

– Type 301 at 232 to 941°C (450°F to 1725°F) . . . 0.54 to 0.63

Tin

– bright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.06

Tungsten

– filament . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.39

Zinc

– polished commercial pure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05

Zinc

– galvanized sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.23

1 2 ... 67 68 69 70 71 72 73 74 75 76 77 ... 81 82

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