The current paper is an overview on previous and ongoing research carried out by the authors concerning the use of Computational Fluid Dynamics for the accurate classification of hazardous Ex areas generated by flammable gases, for the optimization of computational simulation of air-methane mixture explosions by using ANSYS CFX and FLUENT and for calibrating computational simulations of gas explosions using the Schlieren effect. These research works containing analytic studies have led to the observation of basic principles which come to support the benefit of computational approaches for estimating gas dispersion within technological installations in which are handled or stored flammable materials and in which there are likely to occur explosive atmospheres. Preliminary results have led to the idea of developing a computational method for assessing the hazardous area extent in case of gas leak explosions in confined spaces. The computational method intended to be developed has to be validated in the lab using an experimental chamber as domain for analysing accidental flammable gas leaks from transportation installations and for studying the formation, ignition and burning of air-flammable gas mixtures in confined spaces. Results obtained from physical experiments will be used for calibrating the mathematical models. Further, verification and validation of computational simulations carried out based on physical experiments will be performed by a comparative analysis of virtual results with the experimental ones. In the end, the mathematical model will be implemented on a small-scale reproduction of a confined industrial area with explosion hazard.

Abstract. The design, construction and exploitation of electrical equipment intended to be used in potentially explosive atmospheres presents a series of difficulties. Therefore, the approach of these phases requires special attention concerning technical, financial and occupational health and safety aspects. In order for them not to generate an ignition source for the explosive atmosphere, such equipment have to be subjected to a series of type tests aiming to decrease the explosion risk in technological installations which operate in potentially explosive atmospheres. Explosion protection being a concern of researchers and authorities worldwide, testing and certification of explosion-proof electrical equipment, required for their conformity assessment, are extremely important, taking into account the unexpected explosion hazard due to potentially explosive atmospheres, risk which has to be minimized in order to ensure the occupational health and safety of workers, for preventing material losses and for decreasing the environmental pollution. Besides others, one of the type tests, which shall be applied, for explosionproof electrical equipment is the impact resistance test, described in detail in EN 60079 which specifies the general requirements for construction, testing and marking of electrical equipment and Ex components intended for use in explosive atmospheres. This paper presents an analysis on the requirements of the impact resistance test for explosion-proof electrical equipment and on the possibilities to improve this type of test, by making use of modern computer simulation tools based on finite element analysis, techniques which are widely used nowadays in the industry and for research purposes.

No abstract

An important aspect in elucidating the causes of fire events occurence, is the identification of the initial outbreak following on-site investigations. Based on the information resulting from the event footprint (observed thermal and dynamic effects) in correlation with the results obtained in the laboratory tests on the collected samples, as well as the possible generating scenarios of the event, the most probable sources of ignition can be identified. The research team must thoroughly analyze all elements of thermal, mechanical, electrical, radiation, chemical, etc. which may have been present or incidents in the initial outbreak. The computerized fire simulation software will also be used to verify possible scenarios with geometry modeling, combustible / flammable properties of the real case elements, as well as the location of the ignition source, following that the dynamics and propagation directions of simulated fire to be consistent with the case under consideration.

Human behavior in critical situations is at the core of all concerns about the fire safety of buildings, regardless of their destination. The way in which the human caught in the fire reacts to the risk factor to which he is exposed, his behavioral response to the direct action of the fire, or his psychological response to the effect of the fire (temperature, smoke opacity, reduced visibility, exposure to toxic combustion gases), are all factors that can drastically influence the required safe escape time. All these considerations underlie the modern evacuation models used both in the design phase of fire-safe buildings and during the post-event investigation of these undesirable situations. This paper analyzes the possibilities of using the computerized evacuation models and highlights the advantages of using the engineering approach in the field of fire safety. A study was conducted using Pyrosim specialized software and one of the most popular evacuation model, namely FDS+Evac, in order to evaluate the numerical model's capability to predict the occupant evacuation in the case of a presumptive building fire scenario.