The house environment: A methodology for evaluation of hygrothermal conditions

ZAMORA, M. SILVANA; O´DONELL, BEATRIZ

International Journal of Young Conservators and Restorers of Work of Art

Faculty of Conservation and Restoration of Works of Art Academy of Fine Arts

Lugar: Warsaw; Año: 2020 p. 264 - 281

2719-6852

In recent decades, the obvious deterioration suffered by the collections exhibited in museum rooms has become alarming. The lack of environmental control is currently one of the most vulnerable points in the exhibition of objects and works of art in museums.In historic cities, museums are usually housed in old buildings or museum-houses that were not created specifically for the preservation of heritage objects. In this case, preventive conservation includes both the collections and the building itself. The possibilities of creating stable microclimates for the conservation of objects on display are reduced when it is not possible to change its architectural characteristics either due to lack of resources or because it is a priority to conserve the building envelope.The literature indicates that within the criteria of preventive conservation, the monitoring and control of environmental conditions are essential practices to minimize damage to the heritage during the exhibition.The purpose of this work is to present a methodology to evaluate the degree of adequacy of environmental conditions to the exposed heritage in museum-houses through the measurement and analysis of the microclimatic parameters (temperature and relative humidity). The procedure consisted in measuring the temperature and relative humidity conditions of a given space and correlating them with the appropriate conditions according to the material composition of the object, both in average levels and fluctuations. For them, two experimental studies were carried out in three representative rooms belonging to the Historic House of Independence Museum in Tucuman (Phot. 1), Argentina, which is built with two types of materials (brick and adobe). The first, analyzes the evolution of the parameters of temperature and relative humidity in recent years inside a museum-house (2010-2014) and the second, evaluates the degree of adaptation of the heritage exposed to the temperature and relative humidity conditions in specifics works of art (February to May of 2013). The approach is based on a short, medium and long-term field monitoring of the environmental parameters and the measured data are elaborated in terms of average monthly and daily values and mean daily fluctuation. The analysis of the microclimatic data has been carried out according to the Standard ASHRAE for historical buildings and a Performance Index PI for temperature and relative humidity parameters has calculated and related to the potential damage of the works of art exhibited. The results of the analysis of study 1 show that this house is affected significantly by the influence of the climatic conditions, especially during the hottest months of the year. The statistical analysis did not show significant changes in the behavior of the parameters in relation to the characteristics of both types of materials that were used in the building of the museum, which may be related to the location of each room and the opening or not of windows to the exterior. The results of study 2 indicate that the heritage exhibited in the selected rooms is exhibited in inadequate thermo hygrometric conditions, effects that could become visible over time if the conditions are not reversed. During the period analyzed in 2013, only 10% of the time the average levels remained within the levels established by ASHRAE B (Fig. 1). Some daily fluctuations of short periods of RH above the limit allowed of 10% were detected through more quickly by means of an extension of the performance index PI that defines the percentage of time during which the daily fluctuations of temperature and relative humidity were kept inside safe limits.The analysis of the indoor environment through the proposed methodology permits the assessment of the environmental quality in contact with the exposed heritage and the planning of actions aimed at improving the conservation of heritage according to the potentialities of the building. The evaluation of actual levels of variation of the thermo hygrometric variables also determines the most critical variable, which requires constant vigilance of the staff in charge of the collections and the evaluation of success of the applied actions. In the case analyzed, for example, is necessary to implement improvements to control the temperature and humidity levels to bring the PI = 10% index to a percentage of at least 30 or 40%.The application of this methodology together with the collaboration of museum curators will allow the detection of the causes of damage without having to implement the high cost of energetic systems as an alternative solution. The thermo hygrometric behavior observed in this house-museum is typical of the museums in the region and, therefore, the procedure explained could extend to other cases with the purpose of implementing real solutions for a sustainable preventive conservation of heritage.