# GoZone: A Numerical Model for Travelling Fires Based on Cellular Automata Concept
###### Abstract  
Fires in large compartments tend to burn locally and to move across the floor over a period of time; this particular behaviour has been discovered to challenge the assumption of uniform gas temperature in the fire compartment. Recent studies on fires in large compartments have led to the now widely known concept of \"travelling fires\". Several models have been proposed to describe the evolution in time of travelling fires. Although these models represented an innovative step in the field of travelling fires, the major drawbacks of these models can be found in the simplification of fire dynamics (constant spread rate, 1D imposed fire path) and limited field of application (rectangular based geometries). The purpose of this paper is to present a numerical model of travelling fire. The model was based on an improved zone model combined with a cellular automata model. The software GoZone, in which the model was implemented, is intended to be a practical solution to analyse fires in large compartments of potentially any shape. GoZone is aimed to describe the complex dynamics of the fire from ignition to a phase of growing localised fire that may eventually travel in the compartment, possibly followed by a flashover. The main sub models comprising GoZone are presented. A comparison is given with the results of under ventilated fire test 2 of the BST/FSR 1993 test series and with respect to the Veseli travelling fire test is shown. GoZone shows a promising capacity to represent fires in a large compartment in both air and fuel controlled fire conditions. t 2021 11 10679 11.10679 11.10679 11.10679 11.10679 11.10679 1.  
of the fire that attacks the structure, practically, the applicable engineering solutions are essentially limited to compartments in which a fully developed fire is raging or, at best, to compartments where the situation is characterised by a horizontal stratification in two zones (zone models): an upper layer containing hot combustion products and a lower layer of clear air [9; 10]. To date, few models have been proposed for localised fires. The first is a correlation model developed by [PERSON] [11], giving the temperature evolution in the plume centreline when the flame is not impacting the ceiling. There is no information given yet on how this temperature has to be used to estimate the heat flux to structural elements that are not exactly on the centreline of the plume. The second is the correlation model based on the experimental work performed in Japan by [PERSON], which provides the incoming heat flux received at the ceiling level when the flame is impacting the ceiling [12]. There is no information on how this flux has to be used for structural elements such as beams that are underneath the ceiling. A third model, more numerical, has been developed recently based on the computation of view factors from a solid flame to structural elements. This model can, at this stage, be used for any position of the structural elements, but it completely disregards the presence of the hot zone layer that will develop underneath the ceiling [13; 14]. Computational fluid dynamics software have been developed to model the development of fire in building compartments [15]. Such models are extensively used in research projects, but the level of expertise and the CPU time that is required to run such software restricts their use in practical engineering problems to very large projects with consequent budgets. Even then, irrespective of budget considerations, the amount of time needed for each run, typically in the order of several days, does not make such models the best tool for parametric analyses, multiple scenario considerations, or when modifications are made to the compartment during the course of the project. In the last decades, many authors have proposed simple travelling fire models to address the non-uniform temperature distribution and the fact that burning zones are moving in compartment fires.