Sprinkler pipes are longitudinally welded pipes with a wide range of thicknesses and surface finishes. In in order to guarantee the sprinkler system long-term resistance and protection against corrosion, the pipes are manufactured from a continuous hot-dip galvanized steel strip. The target of this work was the characterisation of the effect of different media including inhibitors on the corrosion behaviour of these systems. The corrosion attack is very complex and depends, for example, on the type of coating, the filling medium, the degree of filling and the ambient temperature. For these reasons, a test matrix was defined in which the before mentioned influencing parameters were varied. To be able to test the systems as practically as possible, a special laboratory test stand was used to perform these investigations. The following metallographic and chemical analysis methods showed clear differences. The experiments to characterise the corrosion properties showed that the zinc-magnesium coating is much more resistant to local corrosion than the standard hot-dip galvanised version.