La manutenzione delle infrastrutture urbane a rete ambientale - Maintenance of city infrastructures as environmental systems

Environmental systems, according to a definition given by the same Author, are carriers of matter and energy or energetic matter (fuels) for use of urban environments. Among them there are natural gas lines, water lines, thermal systems for indoor air conditioning, and sewage disposals. To be looked at as an environmental system implies for the system a special care to be paid with reference to sustainability of any action on it including maintenance. Maintenance on demand is common practice that to an approximate evaluation appears to be the cheapest choice, but it seldom meets the requirements of keeping a certain component at a satisfactory level of performance and safety for a given time. Planned maintenance, which includes both preventive and predictive maintenance, is the best practice that assures a continuous level of good performance since it is carried on indipendently of accidental failures. Planned maintenance at given time with given actions assures longer life and more reliable performance to systems. In this work some relevant aspects of maintenance planning are discussed to achieve procedures that can accomplish the purposes of maintenance at the best level of available technology.