Particle-Size Distribution and Light-Extinction Characteristics of Smoke Generated from Plastics (PMMA, PC) under Radiative Heat Flux

Large amounts of smoke generated during combustion processes reduce the visible distance, thereby hindering evacuation operations, if necessitated. The mechanism by which smoke interacts with light depends on the composition and size of the particles constituting the smoke. To ensure evacuation safety, analyzing the main components of smoke and particle sizes that affect light extinction is crucial. In this experimental study, the specific optical density and particle size distribution of smoke with radiant heat flux from an ISO 5659-2 smoke density chamber for Polymethyl methacrylate (PMMA) and Polycarbonate (PC) were measured using a scanning mobility particle sizer (SMPS). Raman analysis was performed to investigate the main components of the smoke particles. During the flame combustion process, the light extinction of 700- to 1000-nm particles reached its maximum, and the specific optical density increased rapidly. However, in decomposition combustion, the size of the particles, at which light extinction reached its maximum gradually increased depending on the intensity of radiant heat and exposure time.