In many places around the world losses in pipelines are extremely high, either in water or in gas pipelines. Today we will concentrate on gas networks. Everyone of you may remember the pictures of serious or even fatal accidents occurring from gas leakages that have not been detected in due time. Moreover gas pollution causes effects that were no longer accepted in modern societies. In the Kyoto protocol from 1997, 37 industrialized countries and the European community committed to reduce emissions to an average of 5 % against 1990 levels. Today gas losses in German networks nearly tend to zero. But this has no always been the case: In most parts of Germany pipelines stem from the age of industrialization in late ninetieth century. Cast iron, mixed material and the use of hemp packing caused a large amount of accidents until the nineteen sixties. Then West Germany started switching from coal gas to natural gas and with German unification in 1990 a second wave of conversion started in the last decade of the twentieth century. This and all other activities have been the result of intensive research and continuous discussions between academics and practitioners in industry, municipalities, private operators and the universities. A non-profit association became the key-player when is comes to implementation in practice. The DVGW is an association of the German gas and water suppliers and has established a set of regulations obligatory to the whole industry: - Establishment of leak categories - Obligatory reaction scheme equivalent to the significance of hazard - Definition and description of equipment and methods of detection As a result of all this the number of leakages and accidents sank significantly over the last 25 years.