Inert gases are more and more utilised in automatic fire extinguishing systems installed also in normally occupied areas. The most commonly used gases are NITROGEN (IG100) and ARGON (IG01). As these are pure gases, practically present in nearly all countries in the world, the (logistic and economic) problems related to refilling are enormously simplified. Gas mixtures are also employed, such as NITROGENARGON (IG55). The gases are contained in various capacity cylinders, at the pressure of 200 or 300 bar.