Measurement of materials emissivity - Influence of the procedure

Abstract

Emissivity is one of the parameters that most influence measurements by infraredthermography, as it rules the effective radiation emitted by the surface, regarding the blackbody. For in situ measurements, the surface emissivity is defined using black tape withknown emissivity. The tape is glued over a portion of the surface under study and itstemperature is measured considering the tape emissivity. The surface emissivity is adjustedby equating the temperatures of the tape and of the surface near it. In this work the accuracyof this method was evaluated, by comparison with measurements made with an emissometer.The emissivity of ten different materials commonly used in buildings was assessed ,considering a black tape of well-known emissivity.