@article{oai:ynu.repo.nii.ac.jp:00010166, author = {Koshiba, Yusuke and Haga, Takuya and Ohtani, Hideo}, journal = {Fire Safety Journal}, month = {Oct}, note = {Owing to depletion risks and the rising cost of phosphate rock, phosphorus-free fire-extinguishing agents are in growing demand. This paper aims to develop a new fire suppressant that does not use phosphates and reports the flame-inhibition properties of calcium compounds: calcium acetylacetonate (Ca(acac)2), calcium acetate (Ca(OAc)2), calcium hydroxide (Ca(OH)2), calcium carbonate (CaCO3), calcium nitrate (Ca(NO3)2), and calcium oxide (CaO). Their flame-inhibition capabilities were evaluated by measuring the downward flame-spread rates over cellulosic fuels on which each calcium compound was adsorbed. Suppression experiments demonstrated that Ca(acac)2, Ca(OAc)2, Ca(OH)2, and CaCO3 extinguished flames. Ca(OAc)2 and Ca(acac)2 were more effective by factors of approximately 1.6 and 1.4, respectively, than ammonium dihydrogen phosphate. To elucidate the influences of the calcium compounds on the pyrolysis of cellulose and char combustion, the activation energy (E) and pre-exponential factor (A) associated with the pyrolysis of cellulose and the char yield (Y) were determined by kinetic analyses involving thermogravimetric measurements. The kinetic analysis permitted us to conclude that none of the calcium compounds hindered cellulose pyrolysis or char combustion. A positive correlation between the bond energy of the compound and minimum extinction concentrations was found, thus suggesting that compounds that easily release atomic calcium effectively inhibit flames.}, title = {Flame inhibition by calcium compounds: Effects of calcium compounds on downward flame spread over solid cellulosic fuel}, volume = {109}, year = {2019} }