Evaluation of sustainability of restoration practices and of techniques of historical know-how

The term sustainability was first defined by G.H. Brundtland in 1987 in the UN report Our Common Future and it is soon become a central key – word of the technical debates of the last decades and those related to the conservation of Cultural Heritage are not excluded. The activity of conservation itself is sustainable, at least for the environmental aspect, since the reuse of the existent avoids the spending of resources to put up new buildings. In the past it has often been considered acceptable the non-sustainability of the restoration against the recognized value of a cultural asset. While this reasoning may still be acceptable for certain outstanding heritage property, it cannot be extended to the widespread ‘minor’ BH: often not declared of cultural interest by Italian legislation and rarely object of public funding. Moreover, in the principal restoration activities of cultural heritage are usually employed chemicals that can have harmful effects both on workers and on environment: the product selection is often affected by economic interests or sectoral advertising. In addition to the toxicity, in the long run these products can produce unexpected negative effects (eg. interactions with atmosphere and pollutants), so the result is a pejorative transformation, in spite of a condition of balance which minimizes the development of the decay phenomena. In order to safeguard both the materials and the operators there is a need of acting on the quality of interventions and on the research of products with low environmental impact. About the quality design it is useful to reminder the maintenance approach whose beginnings are usually identified in the theories of J. Ruskin while about the low environmental impact the application of LCA approach is suggested. As reflection, many ancient goods are still usable thanks to interventions of daily care implemented by the users of the past, so it is also important the revival and experimentation of traditional techniques based on empirical knowledge of natural products readily available (eg vinegar with juice lemon used as a herbicide). The use of these practises appears simple but it must not be taken in a simplistic way: it is necessary to study the scientific reasons at the basis of the functioning of the natural products, in order to use them in the proper manner (eg. the cited mix can cause serious damage to carbonate rocks due to its acidity). In conclusion, the contribute will analyze the sustainability from different point of views of the methodological aspects of different techniques of conservation before and after the advent of the high industrialized processes that took place after World War II, without disclaiming the validity of some applications. Finally the research aims to propose powerful instruments like the LCA approach that could ponders all aspects of social and environmental sustainability and impacts balancing in the long run positive and negative contributions in the entire life of the asset