Fire‐suppression efficiency and extinguishing mechanisms of calcium acetate using heptane cup‐burner flames

Abstract

To address the global requirement for a phosphorus‐free fire‐extinguishing agent, this study elucidated the ability of calcium acetate to extinguish cup‐burner flames. The inhibition efficiency of calcium acetate powder (<50 μm) was compared with that of silica‐uncoated ammonium dihydrogen phosphate (<50 μm), a chemical contained in agents used in typical ABC fire extinguishers. Calcium oxide and calcium carbonate powders were also used to investigate the suppression mechanisms of calcium acetate. The cup‐burner experiments demonstrated that (i) calcium acetate, calcium hydroxide, and ammonium dihydrogen phosphate could extinguish cup‐burner flames; (ii) calcium carbonate could not extinguish cup‐burner flames; and (iii) the fire‐suppression ability of calcium acetate was higher than that of ammonium dihydrogen phosphate, which was in turn higher than that of calcium hydroxide. Thermogravimetric analysis (TG) and X‐ray diffraction measurements revealed that, although the calcium‐compound powders decomposed and produced calcium oxide during flame extinction, significant differences existed among the fire inhibition efficiencies of the calcium compounds. TG and particle‐size measurements proved that the high fire‐suppression ability of calcium acetate resulted from the high ability of calcium acetate to generate inert gases during its decomposition, which diluted the oxygen concentration, thereby extinguishing the fires.