1.1 ,These test methods cover determination of the total normal emittance (Note 1) of surfaces by means of portable, as well as desktop, inspection-meter instruments.
Note 1—,Total normal emittance (ε,N) is defined as the ratio of the normal radiance of a specimen to that of a blackbody radiator at the same temperature. The equation relating ε,N to wavelength and spectral normal emittance [ε,N(λ,)] is
