A Methodological Approach for the Characterization of Hazardous Zones due to Potentially Explosive Atmospheres: a Case Study

Abstract

The biogas role is becoming crucial in the panorama of sustainable development. In fact, Countries of the European Union have agreed on a new 2030 Framework for climate and energy, which includes targets aimed at achieving a more competitive, secure and sustainable energy system. A specific target has established that at least a 27% share of renewable energy consumption must be achieved. Biogas sector is quickly developed in Italy, which is the second biogas producer in Europe, after Germany, and by the end of 2017 about 1,900 plants were operating. One of the main hazards, associated with the biogas production, is the formation of potentially explosive atmospheres (methane is present in biogas composition), deriving from accidental biofuel releases. Indeed, in the industrial plants there are several potential sources, such as valves, flanges, compressors, etc.. The paper illustrates a case study, referred to a biogas production plant. In particular, the paper describes a methodological approach aimed at classifying the places (zone 0 or zone 1 or zone 2 or non-hazardous zone), where potentially explosive atmospheres could occur, and characterizing explosive atmosphere geometry in terms of extent and volume. This topic plays a very important role in order to ensure a safer operation of the plants, because classification of hazardous areas allows to choose equipment and protective systems (according to Atex Directive 2014/34/EU) intended for use in potentially explosive atmospheres. The classification has been carried out in accordance with Atex Directive 99/92/EC, which states the minimum requirements for improving the safety and health protection of workers exposed to potentially explosive mixtures.