Thermophysical Properties Research Laboratory, Inc.
Phone : 765-463-1581

The emissivity of a material is the relative ability of its surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. A true black body would have an emissivity of 1 while any real object would have an emissivity less than 1. Emissivity is a dimensionless quantity.

TPRL, Inc. has two methods of measuring emissivity: the (ASTM C835-06) multi-property apparatus and the table top emissivity apparatus.

The multi-property apparatus is used for conducting solids at high temperatures (up to the melting point of the material).

The table top emissivity apparatus is used at lower temperatures (40°C to 200°C).

Still not sure what is the best testing method for your material? Use our Testing Method Selector Tool to help you decide.

Thermophysical Properties Measured

Thermal Conductivity

Thermal Diffusivity

Specific Heat

Thermal Expansion

Electrical Resistivity


Thermal Gravimetric Analysis & Simultaneous Thermal Analysis


ASTM Methods

Sample Sizes & Definitions

Test Selector Tool

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3080 Kent Avenue
West Lafayette, IN 47906
Last updated 1/5/2012