Non-Halogenated Fire Extinguishants

摘要

The production of halon fire extinguishing agents, which are widely usedthroughout the Air Force, is banned in the U.S. by international agreement, and no environmentally acceptable replacement equivalent to existing halon in toxicity and effectiveness has been identified. It is desired to identify mechanisms by which extinguishants inhibit and extinguish fires to provide a basis for selection of new agents. This project investigated catalytic reactions that remove key species (such as hydrogen) from the flame, and compared and contrasted the roles of heat absorption and heterogeneous reactions in flame inhibition. Flame speed (an indicator of the degree of inhibition) was earlier proven to equate to the amount of heat removed from a burner. Equipment was designed and built to generate particles, to measure the heat extracted from a set of burners (named Sapphire) under atmospheric and subatmospheric conditions, and to identify species in the various regions of the flame. Halon's and other halogenated fire extinguishing agents, phosphorus-nitrogen compounds, and iron-containing compounds were tested. Correlations were made between the heat extracted and (1) the extinguishment of the flame and (2) the fuel/air ratio. A flame molecular beam/mass spectrometer (Sapphire 2) proved to be effective for studying inhibition chemistry. Inhibition by iron compounds was demonstrated, and recommendations for future work were made.