Thermohygrometric monitoring using wireless sensors: study of seventeenth-century church’s microclimatic conditions and enclosed reliquary.

The preservation of religious art work sees the coexistence of opposing needs: first of all the fruition of the works themselves. This is ensured by promoting accessibility to a wider audience and setting up environments improving both the visibility of artifacts and well-being of guests. The second is the obvious need to protect objects exposed to the degradation caused by environmental factors. This can be reachead by creating suitable conditions for their own preservation. Usually the compromise solution is not so simple. The works of art are made up of antique and composite materials; their proper preservation advices vary from case to case according to the kind of materials they are made of. In many cases the ideal environmental conditions for the objects are not compatible with the most appropriate ones for the audience, both in terms of lighting that thermohygrometric ones. The same church circles that house them are extremely diverse and could be structures to be protected themselves. This imposes additional constraints on planning spaces housing artistic object of worship. In this complex scenario is framed the issue of ecclesiastical monitoring and its quality control, particularly from the thermo-hygrometrical point of view. For the ecclesiastical environment there is not a real protocol univocally accepted internationally fixing reference limits for the various parameters. The present discussion therefore refers to those contained by the UNI 10829/99. Whatever the normative code reference, the most suitable approach now widely recognized is still the one so-called “preventive conservation”. This formula means a mixture of measures and strategies, adapted to the case, aimed on minimizing the impact of environmental factors on artefacts displayed and slowing down the degradation. A research line initiated in the eighties - still growing- is focused to the development of sensors and environmental monitoring innovative tools together with new applications on any museum cultural heritage, including ecclesiastics. In order to automate alert situations survey, the first step needed is the simultaneous use of such kind of means able to indicate exceeded preset thresholds. Only in this way the correcting intervention of inadequate conditions becomes systematic. In this scenario the use of thermo hygrometric sensors fits.