Long-term hygromechanical monitoring of Wooden Objects of Art (WOA): A tool for preventive conservation

Museums all over the world are engaged in lively discussions regarding the long-term conservation of works of art made of hygroscopic materials, which are sensitive to microclimate fluctuations, being a potential cause of damage. Wooden works of art are useful in representing the complexity of possible reactions. The analysis of an artefact’s response to short- and long-term variations can supply useful information about its “individual” sensitivity to the exhibition microclimate, suggesting the adoption of more or less rigid parameters. This paper shows, by means of time series and of Principal Component Analysis, how the different sensitivity of wooden artworks to climatic fluctuations can be expressed by means of appropriate parameters, and how a same actual conservation environment may produce different deformational effects on wooden artworks featuring different sensitivity parameters. The shown examples are based on actual recorded climate, and on FEM calculations based and validated by means of actual monitoring on actual wooden artworks. The aim of this paper is to demonstrate how delicate the widening of allowable ranges is and how misleading a generalized approach can be; using simply logged microclimatic data makes possible to formulate a statistical analysis aimed at defining microclimate variance, and efficiently schematizing the greater or lesser stability of the climate