Abstract
The radiation intensity emitted by the surface of an extinguished cigarette coal in a heated environment was compared with the radiation intensity of an artificial blackbody at the same temperature. The experiments were carried out at several temperature levels between 50°C and 125°C. The results indicate that the emittance of the cigarette coal is close to unity. The calculated values based on data obtained within the limits of the experiments varied between 0.997 and 0.91 (average 0.97).