Acid gas production in propane-air diffusion inhibited flames

The proposed replacements to halon 1301, mainly fluorinated and chlorinated hydrocarbons, are expected to be required in significantly higher concentrations than CF3Br to extinguish fires. At these higher concentrations the by-products of the inhibited flames may include correspondingly higher portions of corrosive gases, including HF and HCl. To examine the chemical and transport-related mechanisms important in producing these acid gases, a series of inhibited flame tests are performed with several types of laboratory-scale burners, varying agent type and concentration. A wet-chemistry analysis of the final products of the flames using ion-selective electrodes for F- and Cl- provides an experimental basis for quantitative understanding of the HF and HCl production. Production rates are measured for co-flow laminar and jet diffusion flames. Systematic selection of the agent concentrations, burner type, and air flow rates allows an assessment of the relative importance of agent transport and chemical kinetics on the acid gas production rates. These experimental results are then compared to a model which estimates the maximum HF and HCl production rates based on stoichiometric reaction to the most stable products. The results demonstrate the relative significance of F, Cl, and H in the inhibitor and fuel, as well as the effect of different burner configurations.