In production, processing, storage and transport systems of fluids there are bolted flange joints with ring type gaskets, which connect equipment, lines, tanks or assemblies together. The flanged joint, compared to a welded joint, offers obvious advantages in the prefabrication phase of components or plant sections; moreover, the inspections are easier, the maintenance and replacement of faster components. However, each flanged joint is a potential source of danger if it not maintained with method and competence. Too many accidents and near misses occur every year due to leaks from flanged joints; causes could be, for example, an insufficient specific
knowledge of the maintenance activities, the underestimation of the risks in case of leakage and an inadequate application of the operating instructions.