Thermografic survey of Palatium Vetus in Alessandria

The “Palatium Vetus” of Alessandria was built in 1170, at the time of the founding of the city, and it was the center of political, administrative and judicial of the medieval city. The building was divided into two parts. It included the armory, called Pavaglione, and some administrative offices. The building covers off Via Migliara and continues until Via dei Martiri with various bodies of outbuildings and courtyards. Here were located the offices of Podestà and the “Capitano del Popolo” and in the twelfth and fourteenth courts and prisons. After several ownership changes the building was sold by the City to the State in 1856. In the following years almost all places of Via dei Martiri were sold to private and inside the building facing the square was placed on the guard of the Divisional Command. Early eighteenth century on the side of Via Migliara there were already several shops confirming the age-old commercial destination of the road. Until 1995, the architectural complex housed the Presidium and the military district and is awaiting a new destination.A joint collaboration between Studio BMS Projects in Milan (Head of Operations redevelopment of the entire architectural complex), Studio Ferrari Restauri (in charge of the restoration project) and Research Centre DIAPReM (Department of Architecture, University of Ferrara) made possible imaging survey using the innovative thermal imaging to support the recovery of property of great architectural importance.In the field of photography lighting situations are created naturally or artificially. Similarly, in thermography is necessary the presence of a thermal gradient to produce a proper investigation. There must be a difference in temperature between the object analyzed and a source of heat, which can be represented by the object itself to the surrounding. By an operational point of view, a natural thermal gradient can be replaced efficiently by a thermal field created artificially. An artificial thermal field can be obtained in two ways: by applying thermal stress to the material to cycle (active) or by applying heat to the material suddenly causing an artificial thermal gradient (passive).For a reliable reading of the thermographic data was necessary to artificially create optimal thermal conditions and heat exchange between interior and exterior.