Evaluation of Aerosol Fire Extinguishing Agent Using a Simple Diffusion Model

Aerosol fire extinguishing agents have been recognized as an effective replacement of Halon. The uniform diffusion time and the effective concentration of the aerosol fire extinguishing agent are important parameters for putting out a fire. In this work, the effective concentration is derived based on the diffusion equation, and its variation with changing diffusion coefficient and diffusion time is analyzed. The uniform diffusion time could then be conveniently estimated using this equation. Based on experimental data, the concentration kinetics of the aerosol is drawn and the relation between the diffusion coefficient and the uniform diffusion time is analyzed. It was found that the uniform diffusion time is not dependent on the shape of the closed room but dependent on the total room volume and the position of its diffusion source. This model is demonstrated as a facile tool for the convenient evaluation and reasonable application of the aerosol fire extinguishing agent by predicting the uniform diffusion times of extinguishing aerosol in closed rooms.