Modeling The Ignition Of Soft Furnishings By A Cigarette

This paper describes the user-friendly computer models CIGARET and SUBSTRAT. CIGARET calculates the time-dependent behavior of a cigarette smoldering quietly in the air, away from surfaces. The model incorporates diffusion and convection of gases, as well as the kinetics of char oxidation. It calculates the internal heat fluxes, as well as the internal distributions of temperature, gas velocity, and oxygen concentration. SUBSTRAT determines whether a two-layer solid (with an air gap in between), exposed to a moving heating flux such as is produced by a cigarette, will ignite. Among the processes taken into consideration are three-dimensional heat conduction in the substrate and its pyrolysis. This model has successfully simulated the thermal runaway signifying smoldering ignition of the substrate when it is exposed to a set of external heating fluxes. SUBSTRAT and CIGARET have been designed to work in tandem to simulate the most frequent cause of fatal fires: cigarette ignition of upholstered furniture and bedding. Users' guides are included.