Suppression effectiveness of aerosols: The effect of size and flame type

Abstract

This paper summarizes efforts to identify properties of aerosols (liquids and solids) leading to effective fire suppression. It is part of the US Department of Defense’s Next Generation Fire Suppression Technology Program (NGP) supported by the DoD Strategic Environmental Research and Development Program (SERDP) for identifying suitable replacements for Halon 1301. The number of gas-phase compounds that meet the now stringent list of requirements for suitable replacements is not very large, but there are several condensed phase compounds that offer good fire protection including water and alkali and transition metal compounds. However efficient implementation of liquid or powder aerosol systems is hampered by the lack of a suitable technical database on their fire suppression behavior. Although it is known that size is an important parameter in suppression effectiveness, a quantitative understanding as to the exact role size plays is lacking. Because of this, separating any possible chemical effects from the physical effects which are almost always present is difficult. This project was undertaken to address the lack of quantitative information on aerosol suppression behavior, particularly targeting the effects of size and physical and chemical properties of liquid and powder aerosols. Although the original goals of this project as part of the NGP were specifically targeted for military platforms, the findings are applicable to fire suppression by aerosols in general.