[en] The effort made by Gas Distribution Companies to improve the quality of services rendered to its customers has resulted in their commitment to carry out feasibility studies, aiming at assessing both economic conditions and reliability of technical renewal programmes concerning gas networks. In this article are described: a) an analysis procedure on economic conditions and reliability, in order to detect and classify 'areas' where interventions take priority; b) the results of analyses carried out on a network prototype described and operated by a local computing system. In the above mentioned analysis reference was made both to test results and criteria currently adopted by international Companies with a long experience in a gas distribution