Methane is one of the most common gaseous fuels that also exist in nature as the main part of the natural gas, the flammable part of biogas or as part of the reaction products from biomass pyrolysis. In this respect, the biogas and biomass installations are always subjected to explosion hazards due to methane. Simple methods for evaluating the explosion hazards are of great importance, at least in the preliminary stage. The paper describes such a method based on an elementary analysis of the cubic law of pressure rise during the early stages of flame propagation in a symmetrical cylindrical vessel of small volume (0.17 L). The pressure–time curves for lean, stoichiometric and rich methane–air mixtures were recorded and analyzed. From the early stages of pressure–time history, when the pressure increase is equal to or less than the initial pressure, normal burning velocities were evaluated and discussed. Qualitative experiments were performed in the presence of a radioactive source of ⁶⁰Co in order to highlight its influence over the explosivity parameters, such as minimum ignition energy, maximum rate of pressure rise, maximum explosion pressure and normal burning velocity. The results are in agreement with the literature data.

The dust cloud is the main form of existence of combustible dust in the production area and together with the existence of effective ignition sources are the main causes of dust explosions in production processes. The minimum ignition temperature has an important role in the process of selecting the explosion-protected electrical equipment when performing the explosion risk assessment of combustible dusts. The heated surfaces are able to ignite the dust clouds that can form in process industry. The oil products usually contain hydrogen sulfide and thus on the pipe walls iron sulfides can form, which can be very dangerous from health and safety point of view. In order to study the influence of the pyrophoric sulfide over the minimum ignition temperature of combustible dusts for this work were performed several experiments on a residue collected from the oil pipes contaminated with commercially iron sulfide.

The explosive atmosphere may be caused by flammable gases / vapours or combustible dust. If the amount of the substance, mixed with air, is sufficient, then a source of ignition is needed to cause an explosion. Liquids (for example petrol and other fuels) and solvents from industrial products emit flammable vapours which, when mixed with air, can ignite or explode. At normal temperatures, flammable liquids can emit enough vapours to form combustible mixtures with air, heat, and often thick, black, and toxic clouds of smoke. The behaviour of a fuel-oxidant mixture is characterized by certain explosions parameters, including explosion limits, which characterize the range of concentrations in which combustion propagates at very high speeds. For this work were performed experimental determination of the lower explosion limit for two commercial gasoline samples.

A process known as spontaneous combustion is brought on by the gradual oxidation of flammable organic particles and takes place when air passes over a mass of dust. Combustible powders react with air oxygen in a process known as oxidation, which produces carbon dioxide, carbon oxide, water, and other gases whose contents depend on the temperature at which the oxidation occurs. Combustible dusts can self-ignite depending on their chemical makeup, the characteristics of their constituent components, the particle size and mass geometry, and last but not least, the ambient temperature. Self-ignition is a complicated process that occurs in three subsequent or concurrent stages of development, namely self-heating, humidity evaporation, and self-ignition. Self-ignition is a complicated process that occurs in three separate or concurrent stages of development, namely self-heating, humidity evaporation and self-ignition, all of which interact with one another. Even at normal temperatures, the molecules on the surface of combustible dust particles are prone to exothermic interactions with oxygen in the air conveyed in the free volume between particles, which is the cause of self-heating (or possibly self-ignition). The temperature of the reactive-air dust system will then rise as a result of any heat emitted, hastening the reactivity of other dust molecules with oxygen. By using drying tests at constant temperatures, this work aims to demonstrate the self-ignition behavior of flammable dusts by volume.