Correlation of the smoking tendency of materials

Abstract

Physical aspects of smoke produced in an NBS Aminco Smoke-density Chamber are considered. A theory based on light scattering, light absorption, and particulate coagulation is developed in detail and calculated results are presented to relate the optical density to particulate size and mass concentration. Both flaming and nonflaming modes of material degradation are treated. The theory involves the particulate optical density (POD), a smoke parameter which is the ratio of the optical density per unit length of light path to the particulate mass concentration. Values of POD calculated theoretically for each mode do not vary widely and are in good agreement with measured values for a number of different natural and synthetic polymers. Separate correlations of POD for the two modes enable the prediction of specific optical density provided that particulate mass concentration is known or can be estimated.