Effect of inert agents on the flammability parameters of selected gases and organic liquid vapours

Abstract

Flammable substances may form explosive atmospheres when mixed with air. To prevent their formation or minimise the risk of their occurrence, it is necessary to understand the properties of the mixtures of flammable substances and to apprehend the properties characterising the course of a potential explosion. To minimise the risk of a fire or an explosion, a process called inerting is used in which, e.g. nitrogen plays the role of an inert agent. The article discusses the method for testing the flammability limits, the “bomb” method, in accordance with the European standard PN-EN 1839 and the limiting oxygen concentration (LOC) according to the European standard PN-EN 14756. The study shows the influence of inert gas on the flammability range of selected substances: hydrogen, methane, and hexane, which in practice allows the assessment of the explosion hazard of closed and open spaces, the establishment of safe working conditions, and the selection of equipment operating in given explosion hazard zones. The tests were carried out at 25 °C for hydrogen and methane and at 40 °C for hexane, at ambient pressure.