Roof characterisation related to fire propagation risk by a numerical approach

International audienceThe experience shows that roofing systems are to be considered as a major factor of the fire propagation in industrial buildings like warehouses. Currently in France, regulations require that two main measures be implemented to limit the propagation of the fire by the roof: one is thé use of intumescent strips on the roof; the other consists of extending the fire walls (typically 70 cm or 1 m) above the roof level in order to prevent the flame from being blown down onto roof top. A set of normalised-like live tests is used to study the behaviour of roofing systems submitted to interior or exterior fire. Unfortunately, the aforementioned measures are not easily modelled through live tests, and this prompted the need to develop an accurate computer modelling method. Therefore, this paper presents a computer modelling approach aiming at studying the influence of such intumescent strips or wall upstands on the heat propagation properties of current roofing materials. In this paper, two kinds of roofing Systems are studied: one containing stone wool as insulating material; the other containing polyurethane as insulating material. The numerical code used is Fire Dynamic Simulator12 (FDS), developed by the NIST, with a special additional heat conduction module

Optimisation de l'inertisation de l'arrière-taille à l'azote

National audienceAu cours des dernières années un certain nombre d'auto-échauffements et de feux d'arrière-tailles se sont déclarés dans les chantiers des HBL et HBCM. Ces événements ont eu pour conséquence l'arrêt, parfois définitif, des tailles concernées entraînant des pertes de production sensibles et parfois d'équipements. Dans certains cas, les feux ont provoqué l'inflammation du grisou dans l'arrière-taille, heureusement sans conséquences graves sur le plan humain. Malgré une longue et intense expérience pratique, l'utilisation des moyens de lutte contre ces phénomènes reste relativement empirique quant au choix de la variante la plus adaptée et la plus efficace dans une configuration d'exploitation donnée

Experimental analysis of storage fires for a better understanding of warehouse fires

International audienceLand-use Planning rules applicable in France around listed hazardous industrial premises rely on a deterministic evaluation of the consequences of major accidents such fires, explosions, toxic cloud releases. Major fire scenarios relevant to storage areas shall in this context be carefully analyzed by safety engineers in concerned industrial facilities like large warehouses storing combustible materials. In this background, the French Ministry for Ecology and Sustainable Development currently supports INERIS for the performance of a research program concerning the warehouse fire problem. The program mainly focuses on the development of a methodology addressing the evaluation of the toxic and thermal threats pertaining to warehouse fires. This paper presents a series of large experiments aiming at analyzing the influence of storage configuration on the development and overall behavior of warehouse fires. The document is divided in two sections : the first one presenting the experimental apparatus, the second introducing results derived from the global measurement analysis

Numerical simulation of locomotive fires in the Lyon-Turin tunnel

Generally rail tunnels are not the cause of accidents except when the loss of their structures' integrity is the cause. In fact, the major risk in tunnel is due to the possibility of effects aggravation induced by the enclosed space. Among the possible accidents, fires can induce very problematic evacuation situations and a lot of difficulties for the rescue access and operations. All over the world, important accidents have occurred, with or without victims and they widely justify the research projects such as EUREKA FIRETUN 499 (1) or MEMORIAL TUNNEL (2). Concerning rail tunnels, fires are frequently rolling-stocks fires. Many studies have been conducted on coach fires but few results are published on locomotive fires and their consequences (3). It is true that locomotives have often got security systems for fire detection and extinction and then consequences of these fires are generally reduced to incidents causing only little harm. Nevertheless a fully developed locomotive fire can alter the mobility of a train and therefore the consequences have to be studied as one of the major scenarios for the safety in rail tunnels

A zone model for the prediction of thermal and chemical effects of a pool fire in a forced ventilated enclosure

Zone models have been developed since the early 60s for the prediction of fire parameters such as smoke temperature, smoke filling and movement in multi-compartment buildings. Unfortunately, one major difficulty in current zone models is that heat and chemical species release rates in relation with a given fire source term are usually to be provided as input data. A new zone model for prediction of thermal and chemical effects of pool fire in a forced ventilated enclosure has been developed

Risk assessment of a fire involving combustible materials in a warehouse

International audienceThis paper presents the results of a numerical modeling into a rack fire in warehouse, and an identification of the visible flame shape when a fire is generalised over a whole warehouse after collapse of the roo

Modeling of gas circulation in the goaf of retreat faces/

International audienceFrench coal mines are deep, gassy and prone to spontaneous combustion. The main technique used for mining at Houilleres du Bassin de Lorraine (HBL) consists in retreat faces, mainly as a consequence of strata pressure at a current depth of 1000-1200 m

Application of numerical gas flows modelling to optimisation of nitrogen injections in the goaf

International audienceIn Lorraine Collieries (France), the risk of spontaneous combustion in the goaf of longwall coalfaces is relatively high. Nitrogen injections into the goaf are used to control this risk. However, this practice remains relatively empirical in terms of choice of injection locations and flowrates. Carrying out experiments in the goaf is both difficult and expensive. Thus, the CFD modelling of gas flows (air, methane and nitrogen) is an investigation method well adapted to the situation. For 5 years, a research project has been carried out at INERIS with financial funding from Charbonnages de France and European Coal and Steel Community. So a numerical model has been developed and calibrated using a large quantity of field data and then used for various simulations. The results of these simulations indicate that numerical modelling using CFD codes, such as PHOENICS, is a very efficient tool for improving our knowledge of flows in the goaf and for perfecting the various processes and techniques used to control firedamp and spontaneous combustion. For the particular conditions of the modelled faces, optimal nitrogen injection parameters values can now be determined, allowing increased production, diminution of costs and simultaneously safety improvement. This research is still in progress, in order to make the model more realistic. But computer modelling has already become a powerful and practical tool enabling better understanding of the complex phenomena occurring in goaf of coalfaces , thus being a valuable aid for the mining engineer

Risk assessment of a fire involving combustible materials in a warehouse

This paper shows how a quantitative risk analysis method may be used to evaluate the risk to which the environment of a warehouse may be subjected if a fire breaks out. The purpose of this paper is to present the results the numerical simulations performed with the code FDS [1] in a large volume representative of a warehouse. Evolution of the thermodynamic system is governed by the equations of conservation (mass, energy and chemical species) and by the ideal gas law equation. The results and findings have implications for the modelling of flame spread in warehouse, and for the identification and the assessment of the risks associated with the product storage. Both quantity and type of combustible materials, once ignited, play a major role on the flame height (thermal impact) and on the emission of toxic chemical species, such as carbon monoxide (CO) and soot (C). The present work has been undertaken to study the aspect of gas temperature, velocity, chemical species and radiative intensity during combustion in the case of warehouse fire

Application de la modélisation numérique à l'optimisation de l'inertisation à l'azote

National audienceLa combustion spontanée du charbon et les feux dans l'arrière-taille sont à l'origine de risques très graves dans les chantiers d'exploitation. En dehors des conséquences très importantes sur le plan humain, ces événements peuvent avoir pour effet l'arrêt, parfois définitif, des tailles concernées entraînant des pertes de production et dans certains cas d'équipements. Les moyens de lutte les plus utilisés contre ces phénomènes consistent à réaliser des injections d'azote dans l'arrière-taille