The Influence of Mass Tourism and Hygroscopic Inertia in Relative Humidity Fluctuations of Museums Located in Historical Buildings

Abstract

The preservation of artefacts in museum collections is profoundly affected by fluctuations in temperature and, especially, relative humidity (RH). Since the late nineteenth century, many studies have been carried out into the best way to control hygrothermal conditions. In old buildings located in maritime temperate climate zones (as Portugal) with strong thermal inertia, and which have low ventilation rate (relative to the volume and number of visitors) daily and seasonal hygroscopic inertia may help to assure the maintenance of RH stabilization conditions. The use of expensive active systems may be minimized through passive behaviour of internal finishing building materials. In order to assess the risk of mass tourism and hygroscopic inertia of finishing materials associated with the hygrothermal behaviour of museums, an analysis of several numerical scenarios with a different number of occupants (visitors per hour), different Portuguese climatic zones and finishing materials in order to quantify the risks associated with the fluctuations of relative humidity in a museum. The results of sensitivity studies performed are presented for the case of a museum located in Porto and Lisboa.