Long term prediction of marble erosion and risk analysis for the conservation of the statue of David of Michelangelo

The installation of new HVAC system in museum needs an appropriate inquiry in order to predict every possible environmental modification, which could be detrimental for the sensible materials of the works of art. The importance of the statue of David of Michelangelo in Florence (Italy), which in the last decades was submitted to more than 1.000.000 of visitors per year, focused researchers attention on the implementation of a kind of air ventilation solutions for the preservation of the statue from the action of indoor pollutants. The proposal carried out is related to an air curtain protection system of the statue designed by CITERA of the Faculty of Architecture Valle Giulia in Rome [1] properly simulated by the implementation of a CFD model, to evaluate an homogeneous as possible field in term of air velocity and humidity. The simulation result states that the injection from the bottom of the statue of air with low value of velocity (1 m/s), with controlled relative umidity, and cleaned by an high efficient filtering section, couldn’t carry out any kind of decay for the marble of the statue. Nevertheless, under the suggestion of the Management of the Museum, a study about long term decay phenomena on the marble was developed, in order to evaluate any new possible risk due to the presence of particulate in the air flux surrounding the surface of the statue. A parametric study, based on CFD simulations characterized by the Tulsa model of erosion, has been carried out [2], in order to assess long term effects of the impingement on marble surfaces.