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Flame Extinction by Sodium Bicarbonate Powder in a Cup Burner.

pdf icon Flame Extinction by Sodium Bicarbonate Powder in a Cup Burner. (921 K)
Hamins, A.

Combustion Institute, Symposium (International) on Combustion, 27th. Proceedings. Volume 2. August 2-7, 1998, Boulder, CO, Combustion Institute, Pittsburgh, PA, 2857-2864 pp, 1998.


combustion; flame extinguishment; sodium bicarbonate


An apparatus was developed for testing the extinction efficiency of a solid powder in a coflowing non-premixed flame. Extinction measurements were performed by adding agent quasistatically to the oxidizer stream until flame extinction was observed. The concentration of powder agent was monitored by laser transmission. Extinction measurements were performed on flames burning both liquids and gases using sodium bicarbonate (NaHCO3) powder as the extinguishing agent. For comparison, extinction measurements were also conducted using the gaseous agents, CF3Br (halon 1301) and N2 tests were conducted using a number of fuels including heptane, two jet fuels (JP-8 and JP-5), two hydraulic fluids (83282 and 5606), as well as propane. The agent extinction requirements for the two small particle sizes tested here were highly similar. The results showed that on average, NaHCO3 was three times more effective than CF3Br and five times more effective than N2 on a mass basis in extinguishing flames burning the various fuels. An estimate of agent behavior based on the effectiveness of inert N2 showed that whereas CF3Br acted primarily through chemical kinetic effects, only half of the effectiveness of NaHCO3 could be attributed to kinetics.