Assessment of the effectiveness of a dehumidification system by emission of electromagnetic fields: Proposal of a protocol

In this paper the operation of a dehumidification system has been studied in operating conditions and a protocol for the assessment of its effectiveness is proposed. The physical principle of the used system is based on the interaction of a pulsed electromagnetic field with the masonry materials affected by rising damp phenomena. As it is well known, water has a crucial role in decay mechanisms both by a physical and by a chemical point of view. In fact, soluble salts transport phenomena, biological growth, stress due to expanding clays, freeze-thaw cycles, are among the most diffused examples of decay mechanisms. The target of any dehumidification systems, as the one under analysis, is very ambitious and crucial in the field of cultural heritage conservation; hence starts the authors need in understanding the involved physical mechanisms and in evaluating the effectiveness of these systems. Literature reports laboratory tests carried out with the target to acquire a better knowledge of the interaction mechanism between pulsed electromagnetic field and masonry materials, with and without water presence. Very often laboratory tests are followed by tests on pilot site chosen on purpose. In the example presented in the paper, ground floor masonries belonging to an historical building, with evident rising damp phenomena, was chosen. The building is located at Saltino, Reggello close to Florence, at 995 m asl. The rising of water affects at different levels several rooms of the building at ground floor, but on the north side of the house, the effects are greater. This contribute also proposes preliminary ideas to draw a standard aimed at build up a protocol for the performance assessment of dehumidification systems, based on different physical principles. A full knowledge of physical principles is mandatory to optimize the effectiveness of these systems. The procedure to assess the effectiveness of these systems must be standardized identifying the environmental parameters to be checked in relation to the ones directly measured on the masonry.