In the construction of pipelines for the transport and storage of combustible, corrosive or toxic gases and water-polluting fluids, independent inspections by experts is an essential aspect of quality assurance which contributes significantly to the safety of these systems. This does not only apply to new projects, but also to modifications, conversions or maintenance measures. This approach has proven itself in Germany for many decades and contributes to making these systems some of the safest in the world.