EMISSIVITY MEASUREMENT FOR OUTDOOR STRUCTURES.

Low-emissivity coatings are used to control thermal conditions in structures and reduce heat losses; the emissivity alters during use because of environmental factors, so periodic measurements are required directly on the coating. Existing methods of determining the emissivity epsilon are designed mainly for laboratory conditions. A radiometric method was proposed for measuring emissivity from the functional relationship between the brightness of the emission from a source and the temperature. We have tested this method under field conditions.