Modeling of the process of the extinguishing gas concentration changes in the protected compartment

The Main School of Fire Service, Faculty of Fire Safety Engineering, 52/54 Slowackiego St., 01-629 Warsaw, Poland

^* Corresponding author: sylwiaboron@op.pl

Abstract

The article discusses the aspect of the fire safety of rooms protected by Fixed Gaseous Extinguishing System (FGE-system). On the basis of a literature study, including the analysis of design standards, it was claimed that analytical models of gas outflow from the compartment ignore some parameters that can affect the process of extinguishing gas concentration changes in time. Correct prediction of the gas flow process may affect the retention time value, which is an important determinant of the fire safety of rooms protected by FGE-system. The density of extinguishing gas was indicated as a parameter with a large potential for extending the retention time. It was noted that the density of gas depends on atmospheric conditions like temperature, pressure and humidity, which are omitted in the standard models. In the research part, the concentration distribution of nitrogen and nitrogen-argon mixtures were analyzed using three methods. Obtained experimental data were compared with analytical calculations using a standard model (model N) and a new proposed model extended by an impact of the atmospheric conditions (model PK). Model PK showed greater accuracy of determining the process of extinguishing gas concentration changes. The new proposed model might be a valuable tool for further analysis of gas flow through the room.