Simulations of Moisture Gradients in Wood Subjected to Changes in Relative Humidity and Temperature Due to Climate Change

Abstract

Climate change is a growing threat to cultural heritage buildings and objects. Objects housed in historic buildings are at risk because the indoor environments in these buildings are difficult to control and often influenced by the outdoor climate. Hygroscopic materials, such as wood, will gain and release moisture during changes in relative humidity and temperature. These changes cause swelling and shrinkage, which may result in permanent damage. To increase the knowledge of climate-induced damage to heritage objects, it is essential to monitor moisture transport in wood. Simulation models need to be developed and improved to predict the influence of climate change. In a previous work, relative humidity and temperature was monitored at different depths inside wooden samples subjected to fluctuating climate over time. In this article, two methods, the hygrothermal building simulation software WUFI® Pro and the Simplified model, were compared in relation to the measured data. The conclusion was that both methods can simulate moisture diffusion and transport in wooden object with a sufficient accuracy. Using the two methods for predicted climate change data show that the mean RH inside wood is rather constant, but the RH minimum and maximum vary with the predicted scenario and the type of building used for the simulation.

Climate change impacts on cultural heritage: A literature review

“…D. Saunders (2008) summarized the outcomes of the deliberations, highlighting that previous research on climate change impacts had focused on outdoor cultural heritage, and stressed the paucity of research on the indoor heritage, notably museum collections. This topic has since then gained the attention of many (Ashley‐Smith, 2013; Bertolin & Camuffo, 2014, 2015; Huijbregts et al, 2013; Huijbregts et al, 2014; Lankester & Brimblecombe, 2012a; Leissner et al, 2014; Leissner et al, 2015; Loli & Bertolin, 2018; Melin et al, 2018; Sesana et al, 2019), with all these studies focusing on Europe where an increase in average indoor temperature is generally foreseen, together with small changes in indoor relative humidity, notably a decrease in the South and an increase in Eastern and coastal regions (Bertolin & Camuffo, 2014; Huijbregts et al, 2013; Leissner et al, 2015). These changes have the potential to lead to a gradual and continuous deterioration of the artifacts housed in historical buildings (Huijbregts et al, 2013; Lankester & Brimblecombe, 2012a) through an intensification of deterioration mechanisms.…”

“…Climate change induced variations of indoor temperature and relative humidity in historical buildings can also lead to physical damage of hygroscopic wooden materials (Bertolin et al, 2015; Bratasz et al, 2012; Huijbregts et al, 2013; Melin et al, 2018), and to historic masonry buildings (Cavalagli et al, 2019). When relative humidity is high, wood tends to absorb moisture and mechanical stress occurs during cycles of swelling and shrinkage.…”

Preservation of Cultural Heritage and Resources Threatened by Climate Change

“…At the European level, only two projects, "Noah's Ark" [3] and "Climate for Culture" [4], have finalized their research on these issues. The SI encompass 10 open access papers presenting research studies based on the exploitation of a broad range of data deriving from preventive conservation monitoring [5][6][7] and climate or numerical modelling on material components for assessing environmental impact and climate change effects [8,9]. These papers are focused on a well-assorted sample of decay phenomena occurring on heritage materials, e.g., surface recession and biomass accumulation on limestone [10], depositions of pollutant on marble [11], salt weathering on inorganic building materials [12], and the weathering process on mortars [13].…”

“…With a similar approach to the use of climate, building, and material modelling, Bylund Melin et al [9] propose a study to increase the knowledge of climate-induced damage to heritage objects, which is essential to monitor moisture transport in wood. In fact, hygroscopic materials, such as wood, will gain and release moisture during changes in relative humidity (RH) and temperature (T).…”

Impact of Relative Humidity on Wood Sample: A Climate Chamber Experimental Simulation Monitored by Digital Holographic Speckle Pattern Interferometry

“…Wood plays a dominant role within materials used in cultural heritage (CH) since many art objects from paintings and icons to furniture and statues are made of wood, and/or art constructions are composed to a large extent of wood, therefore wood deterioration is a thoroughly studied subject [5][6][7][8][9][10][11][12][13][14][15][16]. In the last three decades concern for the safe maintenance of tangible and intangible CH has been accelerated due to fears for climate impact and phenomena closely related to climate change and/or extreme events that have tremendous consequence to CH preservation [17,18].…”