Fire Safety Science Digital Archive

The article is discussing methods of extinguishing concentration (EC) determination of gas compositions which intended for volumetric f ire suppression. The article marked, that the "cup burner" method appears to be insufficiently objective and universal. This fact indicates that in case of using this method we always receive overstated EC value in comparison with real conditions of fire suppression. The article offers a more objective way of EC determination that is the "cylinder" method which is based on introduction of the cup with a fire hearth in prepared environment. The EC value is determined as relation between extinction time and EC value. We made analytical research of accumulation process of extinguishing substance in reaction zone of diffusion flame. The accumulation is made by its diffusion transfer from environment. From the results of our research we determined an extinction time equaled 10 seconds. The EC value determine from the diagram "extinction time - EC". After processing of the results we have the following: EC for 23 halon is 8.5 o% vol and for halon 125, 7.3 o% vol