Two new indices for preventive conservation of the cultural heritage: Predicted risk of damage and heritage microclimate risk

The conservation and safeguarding of historic buildings, and of everything that is housed within them, represents a challenge whose value is currently shared at a world level. The conservation of these cultural assets depends on a number of variables, with the microclimate playing a decisive role among them. For at least two decades, scientific literature in the field has been reporting experiences on individual case studies relative to the study of the microclimate and criteria for the conservation of the cultural and architectural heritage, in this regard, standards have also been enacted. Nevertheless, in our view, the research involves stand-alone case studies that are not comparable among one another, in particular with regard to the risk assessment of the place where the assets are located and/or the damage that these assets may undergo as a result of the microclimate of their environment. In this contribution we intend to present two risk indices related to the microclimate: the Heritage Microclimate Risk (HMR) index, which defines the level of risk to which an indoor room is exposed, compared to maximum and minimum values defined according to standards or based on the historical microclimate; and the Predicted Risk of Damage (PRD) index, which links the value of the HMR with the risk of damage to a specific material/object, which is exhibited or conserved within the room. The HMR and PRD are determined by the microclimate variables monitored on site, in particular, Air Temperature and Relative Humidity, or they can be obtained by means of Building Simulation. The proposed indices make it possible to define the potential microclimate risk within a room, as well as the probability that these conditions can cause damage to the objects of value therein conserved (collections, paintings, etc.). As an example, we have reported the application of the two HMR and PRD indices to the case study of a hall of the Royal Palace of Venaria Reale in Turin (Italy).