‘Explosive atmosphere’ means a mixture with air, under atmospheric conditions, of flammable substances in the form of gases, vapours, mists or dusts in which, after ignition has occurred, combustion spreads to the entire unburned mixture.
Legislative Decree 81/08, Title XI, applies to all workplaces in which explosive atmospheres may be formed. It also contains preventive and protective measures.
At the University, explosive atmospheres may be formed in chemistry and physics laboratories, as well as in mechanics laboratories and workshops. Anyone using substances or mixtures that could give rise to explosive atmospheres, or equipment capable of forming them (e.g. wood or aluminium dust), is potentially exposed.
A careful risk assessment based on the analysis of the equipment and working methods is the first and most important preventive and protective measure.
Technical and organisational measures are essentially aimed at avoiding the ignition of the flammable mixture by carefully controlling triggers, at reducing the likelihood that an explosive atmosphere is formed through ventilation, and at mitigating the detrimental effects of an explosion by confining the area.