ISO/NP 26921

Thermal insulation — Determination of the total hemispherical emissivity — Energy comparison method

Scope

This standard defined the spectral directional emissivity and total hemispherical emissivity of opaque insulating materials at the temperature below 700℃, the wavelength changes from 0.4μm to 25μm and the solid angle changes from 0°to 85°in the normal direction by the surface of the specimen. This method specifies the testing principles, apparatus, specimen, steps, the processing of results and reports, using the energy-comparison method.