EXTINGUISHMENT OF ALKALI METAL FIRES

The effects of inert gas blanketing and oxygen partial pressure were evaluated. It was found that reduction of oxygen partial pressure was effective in inhibiting ignition and degree of combustion of lithium, sodium, NaK and potassium. Rubidium and cesium did not ignite, i.e., there was no emission of smoke or flame. Reduced oxygen partial pressure was also effective in inhibiting ignition of alkali metal jet streams. A number of different salts, organic liquids, and polyurethane foam were evaluated with respect to alkali metal fire extinguishment. Met-LX and TEC Powder were the most effective salts which were evaluated. The ratio of TEC Powder/alkali metal was 0.4 for 100 lb sodium fires and 0.2 for 500 lb sodium fires. Polyurethane foam was found to be effective on low temperature (1000F) fires and was useful on alkali metal fires on or under insulation. Organic liquids were not particularly effective on alkali metal fires. A section is presented on a typical alkali metal system which might be used to generate electrical power in space.