Abstract. We report on the radiometric characterization and calibration of the TIR 100-2 (INGLAS Produktions GmbH, 2019) industrial emissometer. This instrument is used for handheld, on-site
directional total emissivity measurements in industrial applications, e.g.,
the measurement of the emissivity of highly reflective thermal insulation
materials. The diameter of the measurement field is determined by two
different methods. The emissometer is calibrated with three different sets
of low- and high-emissivity reference samples. Each calibration is validated
by comparing the results of the TIR 100-2 to directional total emissivity
results of the Emissivity Measurement in Air Facility (EMAF) at the Physikalisch-Technische Bundesanstalt (PTB), Berlin. Finally, the hemispherical total emissivity of highly reflective thermal
insulation materials is determined using the TIR 100-2 according to the
European Standard EN 12898, and, again, the results are validated with
results obtained at the EMAF.