Microclimatic monitoring of the Duomo (Milan Cathedral): Risks-based analysis for the conservation of its cultural heritage

Typically, the structure of old monumental buildings differs significantly from that of contemporary ones. The massive walls, large indoor air volume and the small windows, compared to the opaque portion, drastically affect the microclimates of such constructions. In such buildings is often quite difficult to perform a detailed monitoring campaign of the main microclimatic parameters. In this regard, experimental methodologies and non-invasive equipment, able to minimize the impacts on the building and on its users, should be adopted. This research describes the methodology applied to carry out the monitoring campaign on the Milan Duomo, one of the biggest Cathedrals in Italy. The campaign was carried out by means of non-invasive measuring instruments, in order to keep the building intact and ensure the smooth running of the activities. In a second stage, sensors for the long-term monitoring were installed according to the most significant and accessible points inside the Cathedral. The data collected during one year of monitoring was used to characterize the hygrothermal behaviour of the Cathedral, in order to assess the risks for the main materials which sacred objects, artworks, organs, sculptures and furnishing are made of. The future developments of this work are oriented towards the realization of a simulation model aimed at designing and planning proper active or passive solutions to improve the microclimatic conditions for both artwork conservation and the comfort of visitors.