Effetti del nuovo sistema di copertura sul microclima della Villa del Casale di Piazza Armerina (Sicilia) per migliorare le condizioni di conservazione e il comfort dei visitatori

The musealization process of a cultural site requires a double focus: the conservation of the constituting materials and the well-being of the users. The influence of environmental parameters on material decay is a well-known item: chemical, physical, and biological processes contribute to reducing the expected life of the archaeological or artistic artifacts. Furthermore, the conditions of thermohygrometric comfort are necessary to guarantee the correct use of the site. The paper focuses on the thermohygrometric conditions and indoor comfort for visitors in the archaeological site of Villa Romana del Casale, in Piazza Armerina, Sicily, which is a UNESCO site since 1997. A complex restoration project was performed on this site from 2007 to 2012, aimed at improving the conservation of the mosaic floors, mural paintings and users' well-being, through the new design and consequent replacement of the shelter system. The microclimate monitoring, aimed to verify the environmental conditions created by the new shelters, has been focused on sample room, on which the new covering system has been completed, and rooms that still are covered by the methacrylate old system. The comparison between the environmental parameters related to the old covering system, which caused undesired effects both for fruition and conservation of archaeological findings (mosaics, mural painting, mortars and stone), and the data related to the new covering system, allowed verifying the improvement in microclimatic conditions after the intervention. Data have demonstrated that the new one has reduced temperature inside the rooms and has increased humidity values. These analytical data highlighted that the conservative intervention provided a positive impact on microclimatic conditions. Indeed, the comparison also showed the absence of the dangerous greenhouse effect.